Andrew Mark Hamilton

Female swimming performance and contraceptive pill use

2012-03-31

It�s long been theorised that the fluctuation in hormone levels during the different phases of the menstrual cycle may affect a female athlete�s sport performance. However, many female athletes use the contraceptive pill and here the data is less clear. For starters, oral contraceptives users tend to suffer less severe hormonal fluctuations through the menstrual cycle than non-contraceptive users. Secondly, although there are plenty of studies comparing the sports performance of contraceptive users with that of non-users, there�s relatively little research on how performance changes within the monthly cycle in those women who use contraceptives. But now a new Australian study has been looking at 200m performance in female swimmers and water polo players and come up with interesting findings.

In this study, six competitive swimmers and water polo players completed a 200-m time-trial at three time points of a single oral contraceptive cycle. These points were:
1. During the consumption phase;
2. Early in the withdrawal phase;
3. Late in the withdrawal phase
The split times and stroke rates of the swimmers and water polo players were recorded during the time trial, while heart rates, blood lactate and glucose levels, and blood pH were measured after each performance test. Resting blood levels of the hormones estradiol and progesterone were also assessed.

Results
There were no significant differences were observed between the different phases of the oral contraceptive cycle for 200m swim time, mean stroke rate, peak heart rate, or blood glucose levels. The average peak blood lactate levels were however significantly lower during late withdrawal phase compared with that of the consumption phase and mean pH was also higher (indicating more alkaline blood).
J Strength Cond Res. 2012 Apr;26(4):961-7

Andrew Hamilton comments:
The researchers speculated that the reduction in blood lactate and increase in pH during the withdrawal phase was possibly due to an increase in fluid retention, plasma volume, and cellular alkalosis � ie as a result of water retention. The resulting recommendations based on these findings were that firstly, female 200m swimmers taking oral contraceptives need not be concerned by the phase of their cycle with regard to competition and optimising performance and should not therefore attempt to manipulate their cycle. The second recommendation was that coaches and scientists should exercise caution more generally when interpreting blood lactate results obtained from their female athletes who use oral contraceptives because the phase of an athlete's oral contraceptive cycle is likely to significantly affect the test results.

The truth about BBC Horizon's "The truth about exercise"

2012-03-05

Last week�s BBC Horizon programme titled �The truth about exercise� http://www.bbc.co.uk/iplayer/episode/b01cywtq/Horizon_20112012_The_Truth_About_Exercise/)
provided some interesting and thought-provoking viewing. But just how truthful was it? In nutshell, the Horizon programme presented information about some of the latest thinking on exercise, health and weight loss. � specifically, the use of very short bursts of High Intensity Training (HIT) to produce aerobic fitness/health benefits and also the invaluable role of incorporating more activity into our everyday lives.

The main thrust of the programme was that endless hours of running, cycling, gym training etc are not only impractical for most people but also that they are actually less effective in delivering the health and fitness benefits of just 3 minutes of week of HIT plus more everyday activity (such as walking, manual housework etc).

These apparent benefits of HIT are based on findings arising from recent research carried out at Nottingham University where studies have indicated that sessions of just 3 x 20-second bursts of maximal intensity exercise on a stationary bike can elicit significant aerobic capacity gains (ie improved maximum oxygen uptake and produce the kind of favourable changes in insulin response and blood lipid profiles (associated with a lower risk of diabetes and heart disease) that are NOT seen after steady-state, longer duration aerobic exercise. This research also indicates that while most people can benefit from this kind of training protocol, around 15% of people have a genetic profile that means they don�t seem to get these aerobic benefits (though they do still get the health benefits).

All these benefits for just 12 minutes per month of training seem too good to be true; so to prove a point, the programme�s presenter Michael Mosley (a trained doctor) put himself forward as a guinea pig to test the theory, performing 3 sessions per week for one month of HIT and trying to incorporate more activity into his daily routine. At the end of the programme, he had indeed improved his blood insulin response and lipid profile but had failed to gain significant aerobic benefits.

The verdict
So far, so good � a number of recent studies have shown that short bursts of high-intensity intervals can produce (surprisingly) significant aerobic benefits. Also, the point that HIT is effective at improving blood insulin response and lipid profile precisely because it is intense and therefore good at breaking down muscle glycogen (which triggers these changes) was well made. Another well made point was that incorporating more activity into your daily routine is always a good thing and can add a significant amount to your total calorie burn (the programme highlighted the case of a waitress who was accumulating around 500 kcals per day extra due to the active nature of her work).

However, this was all undone when, at the conclusion of the programme, Mosley�s lack of aerobic response at the end of his HIT programme was discussed. �It�s all down to your genes� was the unfortunate phrase trotted out, leaving the average viewer with the distinct impression that whatever the benefits of HIT, it�s probably not worth exercising because there�s a good chance you won�t respond. This programme also failed on a number of other counts:

� It failed to mention that there are a number of other HIT protocols (eg 6 x 30 seconds at 90% of maximum effort) that have been shown to be effective at enhancing aerobic performance and which might have been successful in Mosley�s case;
� It failed to mention that research has shown that HIT is even more effective when it is performed at the end of a steady-state aerobic session;
� It failed to mention that most people exercise for health and to maintain/lose weight � not to increase maximal aerobic capacity. Unless you�re a competitive sportsman or woman, you probably won�t care if you�re one of the 1 in 7 for whom this HIT protocol didn�t boost maximal aerobic capacity;
� It failed to emphasise that 6 out of 7 people would gain some significant aerobic benefit when using HIT and that everybody would benefit in terms of health;
� When discussing activity and total daily calorie burn, the benefits of structured steady-state exercise were pretty much dismissed. Yes, adding a lot more activity into your daily routine could net you another 400-500 kcals burned per day. However, an hour of jogging or cycling could easily net you 600-1,200kcals, which is even more helpful in the battle of the bulge. Moreover, steady-state endurance exercise is invaluable because it teaches your body how to burn fat more efficiently; people who perform regular, sustained aerobic exercise are better at burning fat for energy � not just during exercise, but at all other times too. The upshot is therefore that if you�ve got a lot of weight to lose, regular sessions of steady-state aerobic exercise will be by far the most effective way to reach your goal.

It�s a mystery why the programme failed to make these other points, which would have provided a far more balanced conclusion and not left viewers with the impression that for many, most forms of exercise are a complete waste of time. Yes, HIT has its place but it�s no magic bullet nor is it a universal panacea!

Warming up: put your back(side) into it!

2012-01-19

In recent years, there�s been quite a lot of research into pre-exercise warm-ups � particularly how best to adapt the warm up to meet the demands of a particular sport or activity � and this has produced some interesting findings, for example that pre-exercise stretching is more likely to harm rather than help subsequent performance. Now, new Australian research has indicated that athletes whose sports emphasise explosive movements would do well to incorporate some gluteal (buttocks) specific exercises into their warm ups.

The research
In the study, scientists looked at the acute effects of three warm-up protocols on peak power production in 22 elite Australian footballers during countermovement jump (where the athlete lands from a jump and immediately launches into another jump) testing. The goal of the study was to devise a practical exercise routine that could be applied as a warm-up immediately before competition matches or weight training sessions.

The players performed two different warm-up protocols plus a �no warm-up� protocol (control condition) over three testing sessions. The two warm-ups followed the same overall structure except that one included a series of low-load exercises targeting the gluteal muscle group while the other included, a whole-body vibration protocol, where the subjects stood on a vibrating platform (frequency of 30Hz) for 45 seconds (some research suggests that vibration platforms can activate muscle fibres, enhancing subsequent power output). The countermovement jump testing was performed within five minutes of each warm-up protocol on an unloaded Smith machine equipped with a linear encoder to measure peak power output, and the results were then compared.

When the data was analysed, the key finding was that peak power production in the countermovement jump test was significantly greater after the warm up that included the targeted gluteal muscle exercises. Meanwhile, the warm up that included the vibration platform was no better in terms of power output than the control � ie no warm up at all.
J Strength Cond Res. 2012 Jan 7. [Epub ahead of print]

Andrew Hamilton comments:
The first implication is that a warm up that includes a low-load exercise protocol targeting the gluteal muscle group is effective at enhancing subsequent peak power output in elite athletes; coaches might therefore want to consider incorporating these kinds of exercises into the warm-up of athletes competing in sports requiring explosive power output of the lower limbs. The other implication is that vibration platforms may not deliver the benefits that are frequently claimed to power athletes seeking the optimum warm up.

Caffeine - how much do you really need for endurance gains?

2011-12-16

When it comes to sport supplements, there�s a lot of hype out there. However, one supplement that lives up to that hype is caffeine. Numerous studies have shown that by stimulating the central nervous system, pre-exercise caffeine can help combat fatigue during endurance activities such as cycling. There�s also some evidence that caffeine can enhance fat burning, which conserves muscle carbohydrate, further boosting endurance.

However, there�s still quite a debate about how much caffeine is need to achieve these performance benefits; some studies have used a dose of 3mgs per kilo of body weight whereas others have used 6mgs or even 9mgs per kilo. The problem of course is that caffeine is not without it�s side effects (eg rapid or irregular heartbeats, anxiety, insomnia to name but a few) so using the minimum required dose that still boosts performance is definitely desirable.

The research
To investigate exactly what is the optimum caffeine dose, Australian scientists took 16 well-trained cyclists and asked them to complete three experimental protocols. In each protocol, the task was the same - to complete a set amount of work equivalent to 75% of peak sustainable power output for 60 minutes � but 90 minutes before each trial, the cyclists were given one of the following:
� 3mgs of caffeine per kilo of body mass
� 6mgs of caffeine per kilo of body mass
� No caffeine (the placebo or �control� protocol)
The scientists then timed the cyclists to see how quickly they could complete their work under each protocol.

The results
Unsurprisingly, when the cyclists took either 3mgs or 6mgs of caffeine per kilo, their performance was significantly improved (by 4.2% when taking the 3mg dose and 2.9% when taking the 6mg dose) compared to when they took no caffeine. However, when the scientists number crunched the data, they found that the increase in performance when taking caffeine was essentially the same regardless of the dose taken � ie the extra 1.3% measured by researchers when the cyclists took 3mgs was not statistically meaningful). They also found that the two doses of caffeine produced the same (reduced) ratings of perceived exertion during the two trials.
J Sports Sci. 2011 Dec 6. [Epub ahead of print]

Andrew Hamilton comments:
Not everybody tolerates high intakes of caffeine so this study makes for encouraging reading because it suggests that you don�t need vast amounts of the stuff to get performance gains. If you�re a �pre-exerciser� caffeine user already, check to see what dose your drinks and gels provide; 200mgs for a typical 70kg adult is likely to be enough for exercise/competition up to two hours in duration!

Cycling for children: start young, live long!

2011-12-10

As any cyclist will tell you, it's an activity that offers fantastic health benefits. Compared to the average British couch potato, cyclists enjoy increased energy levels, stronger and more toned muscles, a reduced risk of heart disease and increased life expectancy - just a few reasons to keep those cranks spinning! Related to this is the fact that adults who cycle to work live longer and are less likely to suffer from heart disease than those who take the bus, train or car. But can children who cycle to school also gain similar benefits compared to their (otherwise active) non-cycling contemporaries?

To investigate this, Danish researchers have been studying the health of 334 children who were aged between 9 and 10 years at the start of the study. The children were monitored over a 6-year period, at the end of which the researchers looked at important markers of heart health including the levels of �good� and �bad� cholesterol in the bloodstream and how well the children were able to metabolise glucose (poor glucose metabolism is an early sign of adult-onset diabetes, which itself is a very big risk factor for heart disease). Of particular interest to the scientists was to compare the results from children who had either mainly walked to/from school or travelled by bus/train/car and then switched to mainly cycling to school.

The findings
This study threw up two main findings. Firstly, at the end of the 6-year study, the children who had switched from either walking or using passive forms of transport to cycle commuting were found to have much healthier levels of blood cholesterol and better glucose metabolism and to be fitter. Because of this, they were considered to have a significantly lower risk of heart disease in adult life. Secondly, the cholesterol, glucose and fitness profiles of the children who walked to school were not really any different from those who were transported to school (by bus, car, train etc)
J Phys Act Health. 2011 Nov;8(8):1025-33

Andrew Hamilton comments:
These results are interesting for a number of reasons. The most obvious reason is that cycling is good for the health of children, and the benefits that can be had are large enough to provide heart health benefits into adult life. Also, they show that simply walking to school does not appear to provide these heart health benefits � something that may surprise a lot of parents. Of course, road safety worries are a natural concern for many parents. But this study suggests than when it comes to the health of your child in later life, cycling to school has much to offer and should be encouraged wherever possible!

Winter flu: 'D-fend' yourself!

2011-11-08

Until quite recently, the scientific boffins were convinced that the only really important function of vitamin D in the body was to build healthy bones and teeth. However, advances in molecular biology have revealed that the biochemistry of vitamin D is actually far more complex and essential for health than we ever imagined. Indeed, many nutritional researchers now believe that vitamin D deficiency is perhaps the most widespread nutritional deficiency across the globe and the cause of many degenerative diseases, including a wide variety of cancers, Alzheimer�s and heart disease.

One reason for this is that vitamin D plays a vital role in maintaining our immune defences. As a result of this, researchers also believe that that low body stores of vitamin D during the winter months play a major role in the spread of influenza. In the summer months, your skin can make vitamin D when it�s exposed to strong sunshine. However, from October-March at our northerly latitude, the sun is too weak to do this and many people develop a vitamin D shortfall as a result.

The evidence
To test the seasonal link between vitamin D status and respiratory infections such as coughs, colds and influenza, a new British study has examined data from nearly 7,000 British adults born in 1958. In particular, the scientists looked at the levels of vitamin D in the bloodstream of all the subjects (most of these vitamin D levels would have been recorded when routine blood tests were performed). They then compared these figures with a number of aspects of the subjects� respiratory health � these included their lung function test results, and how often and when they had suffered from bouts of respiratory disease. They took into consideration lifestyle and other health issues to ensure that these factors didn�t influence the end results. By marrying up the data, they were able to determine whether there was a link between vitamin D status and respiratory disease, and if so, how strong it was.

The results were very clear-cut; the prevalence of respiratory infections had a strong seasonal pattern in the opposite direction to the pattern for vitamin D levels. In other words, the higher the level of vitamin D in the body, the less likely subjects were to suffer from coughs, colds, chest infections, sore throats and flu. In fact the correlation was remarkable; blood levels of vitamin D are expressed as �nanomoles per litre� (nmol/L), and for each 10nmol/L increase in vitamin D, there was a 7 % lower risk of infection. Furthermore, as blood vitamin D levels rose, so did the average lung function of the subjects.
Br J Nutr. 2011 Jun 6:1-8. [Epub ahead of print]

Andrew Hamilton comments:
This is not the first study to show that optimum levels of vitamin D are essential for immunity. However, even though it�s an epidemiological study rather than a clinical trial, it should give us pause for serious thought because the link appears so strong and linear. And given that many studies have also shown the majority of the population (whether through diet or lack of sunshine or both), don�t get enough vitamin D, vitamin D supplementation or a long tropical vacation (or both) could be your best bet of keeping coughs, colds and flu at bay, and those cranks spinning this winter!

Keep your cool for a time-trial PB!

2011-10-05

In theory, the amount of fluid lost via sweating during the time it takes to complete a 10 or 25-mile time-trial isn�t enough to impair your performance. Indeed, in warmer weather, air is slightly less dense, reducing wind drag. Furthermore, studies have shown that a bit of fluid loss (less than 2% of your body weight) is not only harmless to performance but might actually enhance it because it increases your power to weight ratio. However, new Australian research indicates that while these factors might be true, getting hot and bothered yourself is not helpful for time-time trial performance.

In the study, nine trained male cyclists randomly completed four separate 40km cycling time trials in an environmental chamber at 17�C, 22�C, 27�C, and 32�C (all at 40% relative humidity). During the time trials, the cyclists� heart rates, core body temperatures, and power outputs were recorded. The researchers also looked at the variability in the power outputs of the subjects

The major finding was that as the mercury rose, the average power output of the cyclists declined. The mean power output at 17�C was 329 watts but this fell to 324 watts at 22^oC, 322 watts at 27^oC and at 32^oC, power output took an especially big hit averaging just 309 watts. Another finding was that at higher temperatures, the ability to maintain a constant power output also dropped; at 32^oC, power variability was significantly greater than at lower temperatures. These findings may have been related to the cyclists� core temperatures; the core temperature in the final quarter of the time trial was significantly higher in the 32^oC trial than in the trials at 17^oC and 22^oC and the rate of core temperature rise was also greater.
Int J Sports Physiol Perform. 2011 Jun;6(2):208-20

Andrew Hamilton comments:
What do these findings mean for cyclists looking to maximise time-trial performance? The message seems to be that while a warmer environment might enhance some aspects of performance, the increased rise in core temperature it can also produce does not. In practical terms, this means that in very hot conditions, cyclists should not neglect a cooling strategy. This could be as simple as ensuring that your cycling kit on the day is as cool as possible and consuming an iced sports drink immediately before setting off (to help delay the rise in your core temperature). It also suggests that in hot conditions, it�s more important than ever to concentrate on your pacing strategy in order to avoid large fluctuations in pace - something to remember next summer!

Deceive yourself for better performance!

2011-09-13

It�s not new, but the �Central Governor� (CG) theory of fatigue turns a lot of the thinking about sports performance on its head. Basically, CG theory proposes that while the physiological status and feedback from the muscles is important, the brain and its information processing plays a large role in determining how much fatigue we feel during exercise. For example, if you tell an athlete that they�re going to run distance �x� then later suddenly tell them that the run is going to be shorter than they thought, they tend to experience a drop in their perceived level of exertion. Conversely, if you announce the run will be longer, perceived fatigue levels increase. According to the conventional (biochemical) approach to exercise, simply changing someone�s expectations of a workout can dramatically change muscle biochemistry but this is clearly nonsense! And now British scientists have come up with further evidence in favour of CG theory.

In the study, the researchers investigated whether it was possible to reduce the time taken to complete a 4,000-m cycling time-trial by misleading participants into believing they were racing against a previous trial under the same conditions, when in fact the loading (and therefore power output) was 2% greater than the previous trial. To do this, nine trained male cyclists each completed four, 4,000-m time trials:
1. A habituation trial to familiarise themselves with the procedure;
2. A second trial to form a �baseline� measure of performance;
3. A third trial in which the participants raced against an avatar;
4. A fourth trial in which the participants raced against an avatar believing the loading was the same as trial #3 when in fact it was 2% higher (deception condition).
During the trials, measurements of the aerobic and anaerobic contributions to power output were made.

In both races against an avatar (trials 3 and 4), the subjects beat their baseline times. However, more interestingly, the times for the fourth trial were significantly faster than those in trial #3 even though in both instances, the subjects were aiming for the quickest possible time. Moreover, the improvement in times seen in trial 4 (the deception condition) was attributable to a greater anaerobic contribution to power in this trial.

Andrew Hamilton comments:
The authors concluded that: �the provision of surreptitiously augmented feedback derived from a previous performance reduces the time taken for cyclists to accomplish a time-trial of known duration�. What do these finding mean for athletes in general? Well, they tend to support the CG theory by suggesting that in hard efforts of a known duration (eg maximal time-trials), the brain and central nervous system keep a �metabolic reserve� handy (even though we may be unaware of it at the time). They also suggest that this reserve can be accessed by �tricking� the brain into thinking that the body isn�t working as hard as it actually is!
Med Sci Sports Exerc. 2011 Aug 19. [Epub ahead of print]

Train hard (not gently) to live longer!

2011-08-21

Are there any downsides to years of punishing exercise, particularly when it comes to long-term health and longevity? The widely health belief among the general public and many health professionals is that gentle or moderate exercise is beneficial and healthy but intense exercise isn�t. In recent years however, some scientists have carried out studies suggesting that far from being harmful, very intense exercise may be even better for our health and longevity than gentle or moderate exercise.

To investigate this further, Spanish scientists have been investigating the longevity of some of the toughest, hardest trained athletes in the world � previous Tour de France participants! They studied the longevity of 834 cyclists from France, Italy and Belgium who rode the Tour de France between the years 1930 and 1964. The dates of birth and subsequent deaths of the cyclists were obtained on December 31st 2007. From this data, the researchers calculated the percentage of survivors for each age and compared them with the values for the combined general populations of France, Italy and Belgium for the appropriate age cohorts.

The results make fascinating reading because when compared with the general population, there was a very significant increase in average longevity of the cyclists; compared to a typical citizen from these countries, an ex-Tour rider lived on average 17% longer. They also found that the age at which 50% of the general population died was 73.5 years but in the ex-Tour riders, half of them were still alive at 81.5 years of age. The researchers concluded that their findings support the new thinking regarding hard-training athletes such as cyclists � namely that compared to training moderately, training hard is more likely to lead to a long and healthy life, not less.
Int J Sports Med. 2011 May 26. [Epub ahead of print]

Andrew Hamilton comments:
The key point for cyclists (indeed, for any sportsman or woman) here is that this is yet another study (among many others) indicating that you don�t need to worry about the long-term health effects of training hard. Yes, you still need to make sure you get adequate rest and recovery and that you eat well. But you can and should confidently ignore all nonsense and scaremongering from those who claim that punishing training is bad for you. The evidence actually points in the opposite direction � good news for those of us who love to get stuck in and train hard!

Pre-exercise stretching: another nail in the coffin?

2011-07-07

Until very recently, stretching before exercise (pre-exercise stretching) was considered de rigueur for maximum performance and injury prevention. Over the past two or three years however, evidence has begun to accumulate that not only is pre-exercise stretching of little benefit, it can actually impair sporting performance, especially when performed prior to high-intensity exercise such as sprinting or resistance training. Now a new study by Italian scientists seems to show that pre-exercise stretching could also be detrimental for cycling performance too.

The study
In the study, the researchers investigated the effects of a prior bout of passive stretching on subsequent cycling performance in nine male cyclists � specifically how long the cyclists could keep pedalling at 85% of their maximum oxygen uptake (ie hard to very hard) before reaching exhaustion. They also looked to see whether the pre-exercise stretching affected �cycling efficiency�. Cycling efficiency refers to how efficiently you can use the oxygen consumed during cycling to produce the energy required in your muscles to spin the cranks. Increased efficiency means that you need less oxygen to produce the same energy output; since your oxygen supply to muscles is limited, this is a good thing!

The stretching protocol consisted of different static stretches of the muscle groups of the lower limbs involved during cycling: quadriceps, hamstrings, calf muscles and hip flexors. Each muscle group was stretched to the point of discomfort and the stretched position was maintained for 45 seconds with each stretching session lasting approximately 30 minutes.

The findings
Six cycling tests were performed, three with prior stretching and three with no prior stretching, and the results were as follows:
*Compared to no stretching, pre-exercise stretching resulted in a 26% drop in the time to exhaustion (ie the cyclists became exhausted significantly sooner);
*Pre-exercise stretching also resulted in a reduction in cycling efficiency of around 4%, meaning that the cyclists needed more oxygen to sustain a given workload.
Scand J Med Sci Sports. 2011 May 12. doi: 10.1111/j.1600-0838.2011.01327.x. [Epub ahead of print]

Andrew Hamilton comments:
Although more research will be needed to confirm these findings, this study looks to be yet another nail in the coffin for the practice of pre-exercise stretching. The negative effects observed when the cyclists stretched before exercise were probably caused by changes in neural activation of the muscles and viscoelastic characteristics as a result of the stretching. Whatever the reason, these findings suggest that for maximum performance, cyclists (and probably other athletes such as rowers, runners etc) would do well not to stretch immediately before training!

Probiotics: better for boys than for girls?

2011-05-20

In recent years, there�s been a growing interest in the use of �friendly bacteria' (probiotics � found in fermented milk products such as yoghurts) to enhance immunity because some evidence suggests that probiotic use can reduce the incidence of tummy upsets and respiratory tract infections (coughs, colds etc). But just how effective is probiotic use in sportsmen and women?

To answer this question, Australian scientists studied 99 competitive cyclists (64 males and 35 females) for 11 weeks. During this period, the cyclists were randomised into one of two groups:
* Group I � who took one capsule daily of a probiotic supplement containing a minimum of one billion (109) colony-forming units of Lactobacillus fermentum);
* Group II � who took a daily placebo capsule containing an inert substance
As well as measures of self-reported symptoms of illness in the cyclists during the study period, the researchers also measured levels of immune cells in the cyclists� blood before and after the 11 weeks of supplementation and also measured levels of Lactobacillus fermentum in faecal matter.

The findings of the study surprised the researchers because the results of supplementation in the male cyclists seemed to be different to those of the female cyclists. Supplementation in the men consistently significantly boosted Lactobacillus numbers (by 7.7-fold) whereas in the women, the results were much more patchy and inconsistent. When it came to lower respiratory symptoms/illness (chest infections, flu etc), the probiotics seemed to reduce the incidence in the men, giving more protection as the training loads increased, but actually increased it in the women regardless of training load!
Nutr J. 2011 Apr 11;10(1):30. [Epub ahead of print]

Andrew Hamilton comments
Looking at the TV ads, you might be forgiven for thinking that probiotics will boost the health of anybody taking them regardless of gender or circumstance. However, this study suggests that when it comes to cycling at least, it�s the men who stand to gain more benefits, especially as training loads increase. Women on the other hand might not gain any benefits from probiotic use and could even suffer an increased risk of lower respiratory tract infections. One final word of caution: this study also found that both men and women experienced an increased incidence of mild gastrointestinal symptoms when they took these probiotics � worth bearing in mind if you�re someone who summers from a sensitive tummy anyway!

Beetroot juice: it really is 'wonderfuel' for endurance athletes!

2011-05-03

Nitrate and nitrate-containing vegetables such as beetroot have been making waves in the world of sports science recently and with good reason. Two years ago, it was shown that consuming beetroot juice (which is very rich in nitrate) extended the time to exhaustion by over 16% during an incremental cycling test � a very significant result. Then just a few weeks ago, research was published showing that nitrate taken before exercise can help make muscles work more efficiently, using less oxygen to produce the same amount of force and power. However, exciting as these findings are, they haven�t been able to answer that all-important question � can consuming nitrate before competition actually make you faster? But now, a new study by British scientists appears to confirm that beetroot juice really could be �wonder-fuel�.

In the study, nine competitive cyclists performed (separate) 4km and16.1km time-trials as fast as they could under two different test conditions:
* Two hours after drinking half a litre of pure beetroot juice (very rich in naturally occurring nitrate);
* Two hours after drinking beetroot juice that tasted and looked the same but which had had the nitrate removed.
The scientists then compared the times the riders obtained when they drank the pure and �de-nitrated� juice and also looked at their power outputs and oxygen consumption.

The results showed that although the cyclists� levels of oxygen consumption weren�t any different when comparing pure beetroot juice consumption with the de-nitrated juice, the average power outputs generated were significantly higher when pure beetroot juice was taken. This in turn led to remarkable performance gains during the time-trial; the cyclists completed the 4 and 16.1km simulated courses 2.8 and 2.7% faster respectively.
Med Sci Sports Exerc. 2011 Apr 5. [Epub ahead of print]

Andrew Hamilton comments:
Previous studies have shown that nitrate can extend the time to exhaustion in lab tests. However, this study is the first to show that nitrate (in beetroot juice) can enhance endurance performance in a competitive environment - and let�s be honest, that�s what most athletes are after! Moreover, the gains are very significant; in the 16.1km time-trial, the cyclists reduced their average times from 27.7 minutes to 26.9 minutes � that�s nearly a whole minute faster and a much bigger gain in speed than would be gained for example swapping out standard wheels for fancy (and expensive) deep-dish aero-wheels. Given that beetroot juice is also packed with healthy antioxidants and lowers blood pressure, it looks like we�ll be hearing a lot more about beetroot supplementation in the future!

Strength training for cyclists: all together now!

2011-04-27

Cycling is predominately an endurance sport, but when�s all said and done, a cyclist who has good strength and endurance will always perform better than one who has good endurance but poor strength. The problem however is that the types of training needed to build strength and endurance are quite different and to make matters worse, there�s evidence that endurance training performed within 24 hours of strength training reduces the benefits of that strength training. Hardly surprising then that many elite cyclists concentrate on endurance training with minimal emphasis on strength. However, new Danish research suggests that by training strength and endurance simultaneously, we might be able to have our cake and eat it.

In the study, scientists investigated the effects of 16 weeks of concurrent strength (using resistance equipment) and endurance training in young elite competitive cyclists and compared it with endurance-only training. In particular they looked at the capacity of the muscles to produce force, changes in muscle fibre structure and (importantly) time trial performance over 5 and 45 minutes.

As might be expected, the results showed that compared to endurance-only training, cyclists who did both strength and endurance training were able to produce more muscular force in the cycling muscles after the 16-week programme. The strength + endurance group also showed more development of the �type IIA muscle fibres� (endurance fibres that are adapted to high-intensity energy output) compared to endurance-only trained cyclists. Perhaps the most striking finding however was that the strength + endurance group showed an 8% improvement in their 45-minute time-trial performance � an improvement not observed in the endurance-only group.
Scand J Med Sci Sports. 2011 Mar 1. doi: 10.1111/j.1600-0838.2010.01283.x.

Andrew Hamilton comments:
The conventional view of strength training is that while it can enhance sprinting performance, it�s of little use to endurance cyclists and may even hinder endurance performance by �getting in the way� of endurance training. However, this study seems to turn that thinking on its head because it suggests that training both strength and endurance simultaneously not only builds strength, it also enhances endurance in a 45-minute time-trial above and beyond that achieved by endurance-only training. So while the lighter evenings are here, it might not be time to put away that gym pass after all!

Protein power for girls

2011-04-12

Once upon a time, there was only one sports drink in town � the good old-fashioned carbohydrate drink. But go into any cycling or health shop today and you�ll find a whole array of sports drinks, many of which contain protein in addition to carbohydrate. These so-called �carbohydrate-protein energy drinks� claim to improve endurance over carbohydrate-only drinks as well as reduce the amount of muscle damage and accelerating recovery. However, many sports scientists remain sceptical about these claims, partly because the �time to exhaustion� test often used in these studies is not entirely representative of real world racing conditions. That said, the interest remains strong and now new US research on female cyclists seems to add further weight that protein in drinks can help endurance performance.

In the study, scientists compared the effects of two drinks on cycling performance on 14 trained female cyclists and triathletes:
1. A conventional carbohydrate-only drink containing 6% carbohydrate in the form of dextrose;
2. A carbohydrate-protein drink containing only 3% carbohydrate as mixed sugars (1% each of dextrose, fructose, and maltodextrin) but with an additional 1.2% of protein.

The subjects were asked to cycle on two separate occasions for three hours at intensities varying between 45% (easy) and 70% (moderate) of maximum oxygen uptake, which was then followed by a ride to exhaustion at a somewhat higher intensity still. During the testing, the above drinks were consumed at the rate of 275mls every 20 minutes and differences in performance recorded.The researchers found that compared to the carbohydrate-only drink, when the carbohydrate-protein drink was consumed, the endurance of the cyclists in the time to exhaustion ride shot up from an average of 42.3 minutes to 49.9 minutes � a very significant increase.
J Strength Cond Res. 2011 Mar 9. [Epub ahead of print]

Andrew Hamilton comments:
This is not the first study to show that the addition of protein to a carbohydrate drink can extend endurance. But what�s remarkable about this research is that the carbohydrate-protein drink contained less carbohydrate and fewer calories than the carbohydrate-only drink (previous studies have used carb-protein drinks containing at least as many if not more carbohydrate/calories). Because carbohydrate is considered as the body�s premium grade fuel, the carbohydrate-only drink should in theory have performed at least as well, if not better than the carb-protein drink. The researchers were unclear as to why the carb-protein drink performed so well but it does provide yet further evidence that taking protein along with carbs during very long riding sessions could improve endurance.

Nitrate: more evidence it can boost sports performance

2011-03-28

Those with an interest in sports nutrition may have spotted the recent research on beetroot juice and cycling endurance. Published some two years ago, this showed that consuming beetroot juice extended the time to exhaustion by over 16% during an incremental cycling test � a very significant result. Beetroot juice is very rich in a naturally substance called nitrate (also found in a number of other vegetables such as spinach and carrots) and it�s this nitrate that scientists think is responsible for the gains in endurance performance when consumed before exercise. Now new research seems to confirm this �nitrate-endurance� link and also sheds some light as to how nitrate might exert its effects.

In the study, eleven cyclists took either nitrate (in a pure form known as sodium nitrate) or an inert placebo (salt) three hours before exercise. They then performed four bouts of 6 minutes of moderate-intensity exercise on a stationary bike (each bout interspersed with 3 minutes of recovery) followed by an exercise test to exhaustion where the researchers kept increasing the resistance. During this test, the researchers measured how long the cyclists managed to keep pedalling, their maximum power output during the test and how much oxygen they were using.

Unlike the beetroot test in 2009, this study found that the time to exhaustion wasn�t extended by nitrate. Also the maximum power output was the same regardless of whether nitrate was taken. However, what was apparent was that when nitrate was taken, the cyclists used less oxygen for the same work-rate than when it wasn�t taken.
Med Sci Sports Exerc. 2011 Mar 10. [Epub ahead of print]

Andrew Hamilton comments:
These results might not sound exciting but what they appear to show is that nitrate taken before exercise can help make your muscles work more efficiently, using less oxygen to produce the same amount of force and power. Why is this important? Well, ultimately, your capacity to run, cycle, row, swim etc. for long periods of time at moderate intensities is a function of how well your body can absorb and use oxygen. This study, if confirmed, seems to show then that eating a diet rich in certain vegetables such as spinach, beetroot and carrots could help prolong your endurance significantly in longer events.

Caffeine: good news for tea and coffee drinking endurance athletes?

2011-02-11

Caffeine is a popular supplement with endurance athletes for a very good reason: numerous scientific studies have demonstrated that it really can enhance performance by extending endurance and reducing fatigue. However, one question that has remained unanswered is whether the effects of caffeine supplementation before training or racing are reduced in habitual caffeine users (eg regular tea, coffee and cola drinkers) because of �caffeine tolerance�.

To test this theory, Australian scientists have studied the impact of a controlled 4-day caffeine withdrawal period on the subsequent effect of an acute caffeine dose on cycling performance in twelve well-trained cyclists. In the study, the subjects abstained from all dietary caffeine sources for four days before a time trial but ingested capsules twice daily containing either an inert placebo or caffeine (1.5mg per kilo of bodyweight per day). On the fifth day, capsules containing either placebo or caffeine (3.0mg per kilo of bodyweight per day) were ingested 90 minutes before completing a time trial of one hour of cycling at 75% of peak sustainable power output. This protocol therefore compared four conditions:

1. No caffeine ingested prior to day 5 and no caffeine pre-time trial;
2. No caffeine ingested prior to day 5 but caffeine taken pre-time trial;
3. Caffeine ingested prior to day 5 but no caffeine taken pre-time trial;
4. Caffeine ingested prior to day 5 and caffeine taken pre-time trial;

The key finding was that performance was significantly improved after acute caffeine ingestion following a withdrawal period (condition 2 above) and following the non-withdrawal period (condition 4) � ie regardless of prior caffeine use. Moreover, the margin of improvement was around 3% in both these conditions, which was not statistically different.
J Sports Sci. 2011 Jan 25:1-7. [Epub ahead of print]

Andrew Hamilton comments:
Some researchers have speculated that habitual use of caffeine could reduce its impact when used as an ergogenic aid taken before exercise, implying that you might achieve better results by abstaining from caffeine for a few days before using it for sport. However, this study at least shows that this is not the case � the benefits of caffeine are clearly and equally apparent regardless of whether you�re a habitual caffeine user or not. More research will be needed to confirm these findings but these initial results suggest that tea and coffee drinking cyclists/runners/triathletes (the majority!) can enjoy those daily cuppas in the knowledge that should you decide to use caffeine to enhance performance, you�ll gain just as much benefit as those health-conscious caffeine abstainers!

Could a mushroom extract boost immunity in athletes?

2011-02-01

Exercise scientists have long been aware that prolonged and heavy training loads can cause a number of (negative) changes in immune function and also increase the risk of upper respiratory tract infections (URTIs � coughs, colds, flu). Given that this is the time of year that many athletes will be about to pile on the training miles and turn up the intensity, new Slovakian research on a nutritional extract derived from mushrooms makes fascinating reading.

In the study, researchers looked at the effects of supplementing athletes with a substance known as pleuran (an insoluble β-glucan compound derived from the mushroom species Pleurotus ostreatus) on the immune responses and subsequent incidence of URTI symptoms in fifty athletes. The subjects were randomly split into two groups: those who took pleuran for a period of three months and those who took an identical looking but inert tablet (placebo). During the 3-month period, both groups of subjects continued their (heavy) training routines as normal while the incidence of URTI symptoms together with any changes in the efficiency of key immune cells was monitored throughout.

At the end of the 3-month period, the scientists found that compared to the placebo, pleuran supplementation significantly reduced the incidence of URTI symptoms and increased the number of immune called �natural killer� (NK) cells, which are pivotal to immune function. The pleuran also prevented a decline in another key immune function called �phagocytosis� in which invader bugs are literally gobbled up and destroyed by immune cells called phagocytes.
Eur J Appl Physiol. 2011 Jan 20. [Epub ahead of print]

Andrew Hamilton comments:
Your immunity is affected by a number of factors such as your overall nutrition, the balance between emotional and physical stresses and rest and recovery, as well as genetic factors. This means there�s unlikely to be a single �magic bullet� to stop infections and illness and beside, more research in this area is needed. However, the research on β-glucan to date is promising and as part of a balanced nutritional programme, it could turn out to be a useful aid in the battle to stay well and keep training. Indeed, in an earlier study, the same group of researchers discovered that (compared to a placebo) pleuran significantly improved a number of markers of immunity in hard-training athletes. This study goes one step further by indicating that the immune-boosting effects of pleuran seem to be translated directly into reduced incidence of URTIs.

Sports supplementation: are you overdoing it?

2011-01-28

Many sportsmen and women routinely use nutritional supplements to 'top up' dietary nutrient intakes, enhance sport performance or both. However, can you have too much of a good thing? According to new research by German scientists, the answer could well be 'yes'.

In the study, the researchers report on a case study of a highly trained male swimmer competing at international level. The swimmer's habitual energy and micronutrient intakes resulting from food consumption were analysed by 3-day dietary reports. In addition, supplement use and dosage were assessed, and from this, the total amount of nutrient supply was calculated.

The swimmer's diet provided adequate micronutrient content well above the recommend daily allowance (RDA) for all nutrients except for vitamin D. But when supplement use was also added (the swimmer reported the simultaneous use of ten different supplements!), the result was an excess intake above tolerable upper limit for folic acid, vitamin E and zinc. Additionally, daily supplement dosage was considerably above the maximum permitted level (MPL) for nine other micronutrients consumed in artificial products.

The scientists concluded that dietary counselling of athletes should include assessment of habitual diet and nutritional supplements taken intake and that educating athletes to balance their diets instead of taking supplements indiscriminately might be prudent to prevent health risks that may occur with long-term excess nutrient intakes.
Br J Nutr. 2011 Jan 25:1-5. [Epub ahead of print]

Andrew Hamilton comments:
Many studies on nutritional intakes among (even elite) athletes have shown that despite an increasing awareness of the importance of nutrition, a significant proportion are still failing to meet their basic needs for vitamin and mineral intake. However, as this study shows, the indiscriminate use of large amounts of supplements is not the answer either. A better solution is to attend to the fundamentals of your diet first, topping up with a balanced, broad-spectrum multi-nutrient supplement as and when required and under the direction of professional if possible.

Strength train all year round for maximum cycling performance

2011-01-18

It�s winter and the time when many cyclists hit the gym to build strength ready for the start of next season. Conventional wisdom says this is the perfect time for strength training because it doesn�t interfere with in-season training or competition. Besides, it�s hard to get quality miles in when the mercury heads south. But new Norwegian research suggests that saving your strength training for the off-season only may be counterproductive and that all year-round strength training could be a better option for cyclists seeking maximum performance.

In the study, twelve well-trained cyclists were split into one of two groups:

*Strength and endurance � this group performed cycling endurance training supplemented with heavy strength training twice a week during a 12-week preparatory period. The subjects then followed this with a strength maintenance training once a week during the first 13 weeks of a competition period in their cycling season;

*Endurance only � this group performed cycling endurance training only for the whole of the 25-week period.

Following the 12-week preparatory period, the endurance and strength-training subjects increased their thigh muscle size and 1-rep max. However (and perhaps as expected), there was no difference in cycling performance; both groups increased their maximal oxygen consumption and mean power output in a subsequent 40-minute time-trial test.

More intriguingly though, at 13 weeks into the competition period, the endurance + strength training group not only preserved their strength gains but also significantly increased their maximal aerobic power output, power output at a blood lactate concentration of 2 mmol/L and their mean power output in the 40-minute time-trial. These gains were not seen in the endurance-only group.

This study is fascinating because it indicates that when regular strength training is combined with cycling, the strength gains accrued seem to be carried over directly into cycling performance. It also contradicts the conventional wisdom that once the cycling season gets underway, serious strength training should be put on hold until the following winter.
Eur J Appl Physiol. 2010 Aug 27. [Epub ahead of print]

Andrew Hamilton comments:
This study is one of a number of recent studies suggesting that regular strength training can produce cycling benefits above and beyond pure strength gains and reduced injury risk. Although more research is needed, if you�re training in the gym to build strength this winter, you could do worse than to put aside a little time next season to maintain your hard-earned gains!

Cycling: why less could be more!

2010-11-17

If you want to improve your ability to ride hard while minimising the build up of fatiguing lactate in your muscles, you have to do lots of hard training � right? Although you might think so, new German research on elite track cyclists suggests that less could be more and too much high-intensity training could actually blunt your competitive edge.

The scientists studied 51 young male elite German cyclists to see how their daily training over a 15-week period affected their performances during a cycling test. In particular, they wanted to see how the intensity and volumes of training affected the cyclists� ability to produce power at a pre-defined level of blood lactate (4mmol/L) � a lactate concentration that roughly correlates with the onset of anaerobic threshold.

The subjects performed cycle ergometer testing at the onset and at the end of a 15-week basic preparation period, and reported their daily volumes of defined exercise types and intensity categories during this period. After 15 weeks, subjects were split into two subgroups who either improved their performance (responders) or who decreased performance (non-responders), and the training patterns were then compared.

The results showed that responders and non-responders did not differ significantly in the time invested in training or in the total cycling distance performed but they did differ in their cycling intensity distribution. Responders accumulated significantly more distance at low intensity (less than 2mmol/L of blood lactate) while non-responders performed more training at near threshold intensity (3-6mmol/L). Moreover, further statistical analysis showed that these training intensity differences explained the bulk of the discrepancies between the two groups.
Int J Sports Physiol Perform. 2010 Sep;5(3):316-27

Andrew Hamilton comments:
Although we don�t properly understand why, this study indicates that relatively large volumes of low-intensity training help the muscles to perform more efficiently at higher intensities. Some high-intensity work is still required, but too much seems to be counterproductive leading to less efficient performance and higher accumulations of lactate when riding hard.It�s also good news for cyclists who want gains without too much pain because it suggests that plenty of long, leisurely and enjoyable rides may actually be crucial for racing success!

Can runners recover faster from groin pain?

2010-11-08

Chronic groin pain due to adductor (inner thigh muscle) injury is a surprising common injury among runners and one that can be very debilitating. Some recent evidence has suggested that a therapeutic technique called �Van den Akker� manual therapy can help accelerate recovery in runners, enabling a more rapid return to running. In Van den Akker manual therapy, one hand is used to control the tension in the adductor muscles and the other hand is used to move the hip into abduction and external rotation. This flowing, circular motion stretches the adductor muscle group.

To investigate whether Van den Akker� therapy is more effective than a standard exercise programme to rehab adductor injuries, Dutch scientists have compared the two treatments. In the study, patients suffering from chronic adductor-related groin pain for over two months were treated with one of two interventions:
� A home-based exercise therapy and a structured return to running program, with instruction on three occasions from a sports physical therapist
� Van den Akker manual therapy, followed by stretching and a return to running program
The researchers recorded how long it took the patients to return to full sports participation and their subjective levels of pain (using a visual analogue pain scale) at 0, 6, 16 and 24 weeks.

The results showed that compared to the home-exercise programme, those patients who received Van den Akker therapy returned to sports significantly earlier (12.8 weeks versus 17.3 weeks). Interestingly however, during activity there was no significant difference in pain scores between the two treatments and the researchers also noted that neither treatment was very effective in absolute terms, but this latter observation is probably more indicative of the problematic nature of groin injuries in general. Overall, these results suggest that manual therapy might help runners return to running more rapidly when receiving trearment for chronic groin pain.
Man Ther. 2010 Oct 15. [Epub ahead of print]

Vitamin C for swimmers: keep the winter bugs at bay!

2010-10-15

It�s long been known that the risk of upper respiratory infections (URTIs � coughs, colds, sore throats etc) is temporarily increased in those who undergo strenuous training. More recently, a growing body of evidence has emerged indicating that swimmers who regularly train in chlorinated water are particularly at risk because the chlorine derivatives released from the water adversely affect the ability of the nose and throat linings to resist viral infection.

With this in mind and winter approaching, some new Israeli research makes fascinating reading. Thirty-nine young competitive male and female swimmers undergoing heavy training were given one gram of vitamin C per day for three winter months to see whether supplementation affected the rate, length or severity of URTIs.

The results showed that although vitamin C had no effect on the frequency of URTIs, the duration of respiratory infections was 22% shorter in vitamin C group. Overall, the reduction in duration was not large enough to be considered statistically significant but when the results were broken by gender, they showed that vitamin C shortened the duration of infections in male swimmers by 47% (very significant). Moreover, in male swimmers, vitamin C also reduced the severity of the symptoms suffered during an URTI episode.
Eur J Pediatr. 2010 Aug 6. [Epub ahead of print]

Andrew Hamilton comments:
The scientists caution that while more research is needed, their findings merit further investigation, and if confirmed, suggest a daily vitamin C supplement could mean fewer days off in the winter for swimmers who use indoor pools!

Mountain biking: how to reduce your injury risk

2010-09-24

Despite the recent renaissance in road biking, mountain biking remains extremely popular. But despite the absence of cars, mountain bikers are still at risk of injury and now a new Scottish study has attempted to quantify these risks and importantly, how mountain bikers can minimise them.

The researchers looked at the incidence and types of injury needing hospital attention sustained by 130,900 mountain bikers who visited the Glentress Mountain Biking Centre between July 2007 and June 2008. In particular, they were interested in factors that increased or decreased the risk of injury.

Their analysis of the data showed the following:
● 182 bikers sustained one or more injuries during this period;
● One third of these injuries were fractures with men aged 20-29 being proportionately at significantly greater risk than all women and other male age groups;
● Injuries were more likely to occur to the limbs than the torso or head (however, this was likely due to the fact that 98% of bikers wore helmets, which helped protect the skull);
● Injuries were more common in riders using flat pedals (ie non-clipless) and using hardtail (ie non-suspension) mountain bikes and were less common to the lower limbs when riders wore lower body armour.

Overall, the study concluded that per thousand exposures, mountain bikers face a similar injury risk to road bikers (around 1.5 injuries per thousand exposures) but a much lower risk than footballers (4 injuries per 1000 exposures) and rugby players (up to 100 injuries per 1000 exposures!).
Emerg Med J. 2010 Jul 20. [Epub ahead of print]

Andrew Hamilton comments:
The researchers surmised that the higher injury risk for younger male mountain bikers is probably because these riders are more likely to ride aggressively and take risks. The reduced injury risk when using a suspension-equipped bike is probably due to the improved handling and greater stability of the bike over rough terrain and clipless pedals may also help because they prevent the feet slipping off the pedal platform causing a loss of balance.

Overall, this study shows that mountain bikers face a similar injury risk to road bikers and should therefore take sensible precautions, including helmet use, gloves and perhaps lower body armour too. On helmet use, it�s worth noting that in those bikers whose helmets shattered when falling off the bike, 68% suffered no head injury at all while in the remainder (who suffered from concussion and fracture), there were no fatalities.

Heat acclimatisation training: why it could help your winter performance!

2010-09-15

The benefits of acclimatising to hot conditions are well documented; when you�re heat-acclimatised, your body becomes more efficient at losing excess heat in order to regulate its temperature, and this leads to improved hot weather performance. But with winter approaching, heat acclimatisation is probably the last thing on your mind. However, a fascinating new US study suggests that heat acclimatisation training can enhance even cool weather performance!

In the study, twelve trained cyclists performed tests to determine their maximal aerobic power (VO2max), time-trial performance, and lactate threshold (the riding intensity at which fatiguing lactate begins to rapidly accumulate) in both cool (13 degrees C) and hot (38 degrees C) environments before and after a 10-day heat acclimation programme. This programme consisted of rides at 50% VO2max intensity in temperatures of 40 degrees C (hot!). Their results were compared with eight matched controls who took the same 13C and 38C tests but did not undergo the 10-day heat acclimatisation programme (instead they just rode for the same length of time at 50% VO2max in a 13 degrees C environment).

As expected, the heat acclimatisation programme improved performance in the hot (38C) test compared to the control group (VO2max, time-trial performance and power output at lactate threshold increased by 8%, 8% and 5% respectively). What surprised the researchers was that it also improved these three parameters during the cool (13C) test (by 5%, 6% and 5% respectively).

The researchers concluded: �heat acclimation improves aerobic exercise performance in temperate-cool conditions, and provide the scientific basis for employing heat acclimation to augment physical training�. In plain English, performing some hot and sweaty workouts (for example on an indoor trainer or rollers) could help your cool weather riding this winter!
Physiol. 2010 Aug 19. [Epub ahead of print]

Andrew Hamilton comments
These results are surprising because they suggest that the physiological changes brought about by hot weather training can also significantly help cool weather performance. The scientists didn�t speculate exactly how, but they noted that the heat acclimatisation programme boosted blood volume and cardiac output, which in theory could help raise the amount of oxygen circulated to working muscles regardless of how hot or cool the temperatures in which the cyclists rode.

Beta-alanine - why it really could be the next creatine for sprint and middle-distance athletes!

2010-08-25

When given as a supplement, beta-alanine can increase muscle levels of a compound called carnosine, which seems to result in enhanced performance during short-duration (1-2 minutes) maximal exercise in lab testing. The theory behind these observations is that increased levels of muscle carnosine can help offset the build up of fatiguing lactate during high-intensity exercise, high-intensity exercise to be continued for longer.

However, the effects of boosting muscle carnosine via beta-alanine supplementation on competitive athletes are far less clear, but new research on elite rowers by Belgian scientists looks very promising indeed.

In the study, the researchers investigated whether rowing performance was related to the initial muscle carnosine content, and if subsequent beta-alanine supplementation improved rowing performance. Eighteen Belgian elite rowers were supplemented for seven weeks with either a placebo or beta-alanine (5g per day). Before and following supplementation, muscle carnosine levels in the calf muscles were measured and performance evaluated in a 2000m rowing ergometer test.

The results were as follows:

* Even before beta-alanine supplementation, there was a strong positive correlation between 100m, 500m, 2000m and 6000m speeds and muscle carnosine levels (ie rowers with naturally higher muscle carnosine levels tended to post the highest speeds);

* After beta-alanine supplementation, average muscle carnosine levels increased by 45.3 % in the soleus and 28.2 % in the gastrocnemius muscles of the calf � there was no such increase in the placebo group;

* Following supplementation, the beta-alanine group knocked an average of 4.3 seconds off their 2000m times compared to the placebo group. Moreover, the degree of muscle carnosine elevation produced by the beta-alanine supplementation was directly correlated to the 2000m-performance enhancement.

This research provides further and convincing evidence that a) beta-alanine supplementation elevates muscle carnosine levels, b) these increased levels of muscle carnosine do improve high-intensity exercise performance and c) that the performance enhancement that results can be significant for elite athletes!
J Appl Physiol. 2010 Jul 29. [Epub ahead of print]

Andrew Hamilton comments:
Back in the 90s, the use of creatine as a sports performance enhancing supplement shook the world of sports nutrition because it did exactly what it promised on the tin. Since then, many more so-called 'performance-enhancing' supplements have appeared on the market (eg ribose, nitric oxide enhancers etc) but subsequent studies have shown most of them to be completely ineffective. Beta-alanine looks to be very different though as nearly every study into its effects on sport performance (specifically improving the ability to sustain high-intensity workloads) is producing positive results. If you take your sport seriously, this is one supplement to keep an eye on!

Two bike rides a day keeps the doctor away!

2010-08-17

As the purse strings tighten in these tough economic times, cutting down on car use and cycling to work makes a lot of financial sense. And now new research carried out by Dutch scientists also shows that in addition to the fitness benefits, it could keep you significantly healthy too.

In the study, researchers examined the association between commuter cycling and the incidence of sickness absence in 1,236 Dutch employees who answered a self-report questionnaire that examined commuting habits over a one-year period (May 2007-April 2008). In particular, the scientists were keen to discover whether there was any link between daily distance cycled, the riding speed and absenteeism.

When they number-crunched the statistics, they found that employees who cycled to work were less likely to need time off work due to sickness � the non-cycling employees taking on average more than one whole extra day off work due to sickness compared to their cycling colleagues. This was largely explained by the significantly higher proportion of people with no absenteeism at all in the cycling group. They also found that there was a dose-response relationship between the speed and distance of cycling, and absenteeism. Compared to those who cycled just a short distance (less than 5km three times a week), commuters who cycled more often and longer distances were absent for fewer days on average.
Prev Med. 2010 Aug;51(2):132-5

Andrew Hamilton comments:
This is just one more study showing that regular vigorous exercise is not just beneficial for long-term health, it also strengthens the immune system, thereby reducing the risk of picking up day-to-day infections such as coughs, colds, sore throats and flu. For many people, cycling to work can be an excellent and time-efficient way of exercising, being quicker and cheaper than driving, and saving money in the process. Remember too that healthy employees are a great asset to any company � could be useful if you�re trying to negotiate a much-needed pay rise!

Calcium supplements and heart disease - a closer look at the evidence

2010-07-30

Some people who are at risk of developing osteoporosis (literally meaning porous bones � a condition that can dramatically increase the risk of fracture) have been advised to take calcium supplements. But can calcium supplements increase the risk of heart disease? A new study published in the current issue of the British Medical Journal suggests they might.

In the study, the researchers pooled the data together from 11 previous studies (a so-called 'meta-study') on calcium supplements and heart disease risk to help them draw firmer conclusions. In particular, they looked at men and women with an average age of 72 who took more than 500mgs per day of calcium and for an average of 3.5 years.

What the scientists found was that although very few of the 11,000 subjects in their pooled data suffered a subsequent heart attack, those who took calcium supplements were about 30 percent more likely to have a heart attack than those did not. This has prompted some doctors to question the wisdom of giving calcium supplements to patients at risk of osteoporosis, especially as the evidence they significantly lower the risk of this disease is patchy at best.
BMJ 2010;341:c3691

Andrew Hamilton comments:
Although it makes a good headline, people who take calcium supplements shouldn�t panic just yet! Firstly, the risk of heart disease in the subjects was actually very low and a 30% increase in a very low risk is still a low risk.

Secondly, this study looked at those taking calcium-only supplements � not calcium combined with vitamin D (which helps calcium to work in the body) or calcium combined with other vitamins or minerals such as magnesium. This is important; many calcium supplements combine calcium with vitamin D and studies have shown that higher intakes of vitamin D may actually help reduce the risk of heart disease.

Moreover, we know that higher intakes of magnesium are associated with a lower risk of heart disease, especially in men. Calcium and magnesium work as a team in the body; taking high amounts of calcium on its own may therefore hinder the absorption/utilisation of magnesium, which could at least partly help explain these findings

Thirdly, studies have also shown that dietary calcium does not have any negative effect on the risk of heart disease. Indeed, diets providing higher levels of calcium actually lower the risk of heart disease compared to a low-calcium diet.

If you�re taking a calcium-only supplement for osteoporosis, you might want to discuss with your GP what the best course of action is, especially if you�re in a high-risk category for heart disease. In the meantime, there�s insufficient evidence just yet that otherwise healthy people who take calcium supplements combined with other nutrients should discontinue this practice.

Shorten your running stride length for lower injury risk

2010-07-14

Can adjusting your stride length while running reduce the shock associated with footstrike and lower your risk of injury? According to new US research just published by scientists at the University of Wisconsin, the answer could well be yes!

In the study, researchers examined 3-dimensional kinematic data acquired from 45 healthy recreational runners who altered their stride length while treadmill running at different gradients but at a constant speed. In particular, the scientists were interested to see how changes in stride length affected the biomechanical loading of the hip, knee and ankle joints

The researchers discovered that reducing stride length by just 5% (and increasing speed to compensate) significantly improved energy absorption and reduced shock by around 20% at the knee joint. A 10% reduction of stride length resulted in significantly less shock at both the knee and the hips joints and also resulted in improved energy absorption at the ankle joint.

According to researchers, their previous studies have shown that most runners can accommodate a 5% shortening of stride length quite easily without affecting their overall running gait. The pay-off for those that can could be a significantly reduced risk of injury.
Med Sci Sports Exerc. 2010 Jun 23. [Epub ahead of print]

Andrew Hamilton comments:

I spoke to Professor Heiderscheit, the author of this study. He explained that quite apart from the reduced risk of injury with a shortened stride length, the potential implications for triathletes in particular could be significant: �The reduced mechanical energy absorption that occurs with a 5% shorted stride length preferentially unloads the quadriceps; considering the quadriceps� contribution to biking, reducing the work required of this muscle during the running leg should be advantageous. The good news is that a 5% shortening of stride length is quite modest and most triathletes and runners have found this easy to achieve. A further advantage of course is a reduced risk of injury.�

Carbohydrate drinks: why two sugars really are better than one!

2010-05-28

A recent development in carbohydrate drink technology is the addition of the fruit sugar fructose to conventional glucose-based drinks. Research has clearly shown that this blend of sugars means more carbohydrate can be transported to the working muscles for use as energy during endurance exercise. And since more energy is available from the carbohydrate consumed in a glucose/fructose drink, this in turn should spare stored muscle carbohydrate (glycogen), resulting in superior endurance compared to conventional glucose-only drinks.

To test this theory, nine male competitive cyclists (average age 32.6 years, average maximum oxygen uptake 61.5mls/kg/min) completed two simulated 100km cycling time-trials on an electronically braked cycle ergometer, with trials separated by 5-7 days. During the time-trials, the participants drank 250mls of one of two carbohydrate solutions every 15 minutes.

The two carbohydrate solutions looked and tasted identical and both contained 144g of carbohydrate per litre. But in one trial, subjects were given the carbohydrate as a conventional glucose-only drink while in the other, the drink consisted of a glucose/fructose blend. The results showed that all nine cyclists completed the 100km time trial significantly faster when they received the glucose/fructose beverage compared to the glucose-only drink (204 vs. 220 minutes respectively � ie 10% faster!).
Int J Sport Nutr Exerc Metab 2010 Apr;20(2):122-31

Andrew Hamilton comments:
There�s plenty of theory supporting the use of glucose/fructose energy drinks over conventional glucose-only drinks; glucose/fructose drinks are absorbed more rapidly and result in more energy availability from the ingested drink. The reason is that because fructose is absorbed into the bloodstream using a different pathway to glucose, extra carbohydrate can be absorbed even when the glucose absorption pathway is already maxxed out. Then once the fructose has entered the body, it can be converted to glucose to help boost the energy supply to hard-working muscles. More importantly though, this study shows that these theoretical benefits actually translate into real performance gains, which is obviously what counts. As always however, don�t forget that your day-to-day dietary carbohydrate intake remains as important as ever!

Could cycling be bad for bone health?

2010-05-24

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�It�s a well-established fact that vigorous weight-bearing physical activity is very effective at helping to build BMD �in the early and mid years of life. This is important as low BMD levels significantly increase the risk fracture and of developing osteoporosis (quite literally 'porous bones') later in life � a serious condition that can dramatically reduce quality of life and lead to numerous health complications.

Cycling is generally recognised as one of the best forms of exercise there is. However, the low-impact, smooth spinning nature of the pedalling action leads to only low loading of the bones, which although kind to joints, doesn�t appear to offer the same bone mass building benefits of say running or weight training. Moreover, some studies have reported that competitive road cyclists have lower bone mineral density (BMD) than non-cyclists, suggesting that high-volume, non weight-bearing exercise may actually be detrimental for bone health. And now a new study on pro cyclists appears to suggest that these concerns are well founded.

In the study, scientists in Sweden, France and the UK compared the BMD at several sites of 30 male professional cyclists with 30 similarly aged males (controls) using an advance and accurate technique known as dual X-ray absorptiometry (DXA).

The cyclists were all racing in professional teams at the time of the study, and had participated in at least one of the main 3-week stage races (Giro d�Italia, Tour de France or Vuelta a Espana) in each of the previous three years. The controls were all healthy but had cycled less than one hour per week and had not performed weight-bearing exercises (ie running or resistance training) for more than 1 hour per week for three years prior to the time of the study.

The results showed that overall, the pro cyclists had significantly lower levels (9.1% less) of BMD than the control group; more worrying was that in the lumbar vertebra of the lower back and femoral neck (ball joint at the top of femur), BMDs were 16% and 18% lower respectively. This study adds weight to the argument that cycling on its own isn�t enough to provide bone health benefits.

Andrew Hamilton comments:
Although this study examined pro cyclists training/racing for upwards of 22-25 hours a week, regular cyclists concerned about bone health should take note. Resistance training and running are both excellent bone mass builders, and according to the study�s authors, adding small amounts of these activities into your weekly programme is not just an excellent bone health insurance policy, they could even help improve your cycling!
Int J Sports Med. 2010 Apr 29. [Epub ahead of print]

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Cherry juice reduces muscle pain during running

2010-05-18

Cherry juice has been attracting increasing attention from sports nutritionists in recent years; a number of studies have suggested that consuming cherry juice prior to a bout of vigorous exercise can help protect the muscle tissues against damage cause by oxidative stress, reduce the symptoms of muscle trauma following exercise and also accelerate recovery after exercise. Now a new US study indicates that cherry juice could help reduce the amount of muscle pain experienced as a result of distance running.

In the double blind, placebo-controlled study, 54 healthy runners (36 male, 18 female, average age 35.8 years) ran an average of 26.3kms over a 24-hour period. Participants were split into two groups and ingested either 355ml bottles of tart cherry juice or a placebo cherry drink twice daily for seven days prior to the event, and on the day of the race. All the participants assessed for �level of pain� on a standard Visual Analog Scale (scored from 0-100) at baseline, before the race, and after the race.

The results showed that while both groups reported increased pain after the race, the tart cherry juice group reported a much smaller increase in pain (an increase of 12 units) compared to the placebo group (an increase of 37 units). Statistically, this difference between the two groups was very significant, indicating the cherry juice had reduced post-exercise pain.
J Int Soc Sports Nutr. 2010 May 7;7(1):17. [Epub ahead of print]

Andrew Hamilton comments:
Ideally, this study would have also included measures of muscle damage in the two groups; a lower level of muscle damage in the tart cherry juice groups would have provided an even stronger levels of evidence for these benefits. Nevertheless, these results add to the growing body of evidence that certain types of fruit juice such as cherry and chokeberry can help reduce muscle damage and associated symptoms associated with vigorous exercise.

Measuring your cycling fitness the simple way

2010-05-05

How effective is your training regime at building cycling performance? While elite cyclists and their coaches have access to expensive laboratory testing facilities, answering that question is harder for us mere mortals. However, new research just published in the International Journal of Sports Medicine suggests that a simple time-trial test could be an extremely effective solution for monitoring cycling fitness.

In the study, scientists at the University of Exeter took 15 elite and nationally ranked male cyclists and measured their maximal performance using three methods (see below) to see how closely correlated the results from the lab and the time trials were:

● A graded exercise test to exhaustion in the lab on an exercise bike during which blood chemistry and oxygen usage was monitored to determine physiological measures of fitness such as lactate threshold and maximum oxygen uptake;
● A flat-out 4-minute time-trial performed outdoors on a road bike with power output measured using an SRM power meter;
● As above using a 20-minute time-trial.

The results showed that the power output measured during the 4-minute time-trial was significantly correlated with the maximal power output during the graded exercise test. Moreover, the measured power output during the 20-minute time-trial closely correlated with the �respiratory compensation point� (where blood lactate rises suddenly, accompanied by the onset of hyperventilation).

What this study suggests is that 4 and 20-minute time trials can be every bit as revealing as expensive and time-consuming lab tests when it come to measuring cycling performance. Dr Alfred Nimmerichter, head of the research, also comments that in his experience, the results from lab tests are often a poor indicator of actual performance (racing results and subjective perception from the riders). He adds that these time-trial tests are reliable and easy for athletes and coaches to apply and integrate into most training regimes.

NB. This news item is also published in Cycling Weekly

Andrew Hamilton comments:
Although this study used (expensive) SRM power meters to monitor performance, you can still take advantage of the main findings with a simple bike computer by measuring the distance you can cover over 4 and 20 minutes of maximum effort and comparing results as the season progresses. An increase in your 4-minute distance indicates a rise in your maximum power while an increase in 20-minute performance indicates an improved anaerobic threshold.
Int J Sports Med 2010; 31: 160 � 166

High sugar consumption: are you risking your health?

2010-04-21

Thanks to public information campaigns, most of us are aware of the link between high levels of fat consumption and the increased risk of heart disease. But with this focus on fat consumption, have we taken our eye off the sugar consumption ball? A newly published study by US scientis�ts suggests that not only are high levels of sugar consumption bad for heart health, but also that many of us are consuming more sugar than we should.

In the study, the researchers looked at levels of sugar consumption and the effect on blood lipids (fats), in particular the levels of LDL cholesterol (bad cholesterol, associated with an increased risk of heart disease) and HDL cholesterol (good/protective cholesterol, associated with a reduced risk of heart disease).

A total of over 6000 adults had their diets analysed for the content of added sugars in the foods in their diets (naturally occurring sugars such as those in from fruits and fruit juices were not included). The subjects were then grouped according to sugar consumption:

Less than 5% of total calories;
Between 5% and 10% of calories;
Between 10% and 17.5% of calories;
Between 17.5% and 25% of calories;
Over 25% of total calories.

The results showed that the average intake of sugar across all groups was 15.8% (this compares with an intake of 10% or less recommended by health professionals). More worryingly, the levels of protective (good) HDL cholesterol steadily fell as sugar consumption rose. The researchers also found that the higher the sugar intake, the higher the levels of blood triglycerides (fats) generally � not desirable since higher blood triglycerides are also associated with an increased risk of heart disease.

The scientists concluded that there study showed �there was a statistically significant correlation between dietary added sugars and blood lipid levels among US adults" and went on to add that �for the sake of their long-term health people should look at how much added sugar is in their diet and find ways to cut it down.�

JAMA, Vol. 303 No. 15, April 21, 2010

Andrew Hamilton comments: While much attention has rightly been focussed on health and saturated/ processed fat consumption, this study serves to highlight that while sugar is a carbohydrate, sportsmen and women should try to ensure that the bulk of their carbohydrate comes from starchy foods such wholegrain rice, breads, cereals and pasta, potatoes, beans/lentils etc. Not only do these carbohydrates provide plenty of healthy fibre and vitamins/minerals, they release their energy more gently into the body with far less disturbance to the delicate mechanisms of blood glucose control. Most sugar in the diet comes courtesy of that added by the food and drink manufacturers. If you want to cut down on sugar consumption, be sure to check all labels carefully!

Magnesium supplementation raises testosterone levels in athletes

2010-04-06

�Magnesium is a vital min�eral for the human body. Not only is it essential for the enzyme that synthesises ATP (the body�s �universal energy molecule� and which powers all movement and much of the body�s chemistry), it�s also required for protein metabolism, proper immune function and a healthy cardiovascular system.

In recent years however, there�s been evidence that increased intakes of magnesium can naturally raise levels of the hormone testosterone in the body � something that has sparked much interest among strength and power athletes - and now a new study just published by scientists in Turkey seems to provide further evidence for this effect.

In the study, the researchers assessed how four weeks of magnesium supplementation and exercise affected the free (thought to be the most biologically active form) and total levels of testosterone in the blood of sportsmen practicing tae kwon do and inactive subjects (control group). The study groups were as follows:

Group 1 - sedentary controls, supplemented with 10mgs of magnesium per kilogram of body weight per day;
Group 2 - tae kwon do athletes practicing 90-120 minutes per day supplemented with 10mgs of magnesium per kilogram body weight each day;
Group 3 - tae kwon do athletes practicing 90-120 minutes per day and who received no magnesium supplements.

The testosterone levels in the athletes were determined in four ways: resting/no supplementation, after exercise/no supplementation, resting with supplementation, and after exercise/with supplementation. The sedentary groups were tested before and after magnesium supplementation.

The results showed that, as expected, the athletes had higher levels of free testosterone than their sedentary counterparts; exercise (providing it�s not excessive or exhausting) is known to raise levels of testosterone. What was interesting however was that magnesium supplementation significantly increased testosterone levels in athletes taking it compared to those who didn�t. This effect was also observed to a lesser extent in the sedentary control group.

These results are intriguing since numerous studies have shown that a large proportion of the population in the West (sportsmen and women included!) fail to meet even their most basic dietary magnesium needs. This research adds further weight to the importance of magnesium intake for athletes.

Biol Trace Elem Res. 2010 Mar 30. [Epub ahead of print]