2010 Studies & Research Blog

For every serious athlete, from the bodybuilder preparing to hit the stage to the swimmer trying to maximize performance while retaining muscle mass, meal planning is an essential part of the fitness equation.  Even weekend warriors and non-competing gym rats want to make sure that they are complementing their training sessions with the proper nutritional protocol.  After all, the well-worn phrase, "You are what you eat," is probably taken more seriously by athletes and fitness enthusiasts than anyone else in society today.

Those knowledgeable about the importance of nutrition in athletic endeavors can easily rattle off the basics of a highly effective diet - one should consume complex carbohydrates for sustained energy, protein for building, retaining and repairing muscle, and dietary fat for hormone regulation, transport of nutrients and construction of many bodily structures.  In addition, all athletes should be consuming ample amounts of water to prevent dehydration.

But selecting the proper foods and beverages is only part of the equation.  The other, often-debated aspect of high-performance nutrition is meal timing.  After all, you can fill your car with the highest grade of gasoline in the world, but you’re not going to get anywhere if you don’t put it in at the right time - before you need to travel.  Similarly, making sure that you fill your body with the right nutrients at the right times is a crucial component of any complete fitness plan.  For the most part, athletes put the biggest emphasis on meals that fall around their training sessions - pre and post-workout meals.  In fact, strength and figure athletes often view the post-workout meal as the most important one of the day.  But that’s not really a contested subject.  However, the timing of the rest of the days meals is hotly debated.

One of the most popular postulates is that meals should be spread evenly throughout the day for optimum absorption of nutrients and to repeatedly stoke the metabolism.  Those taking this view feel that smaller, more frequent meals are preferable to a few larger, less frequent meals.  The argument is that frequent eating will allow one to take advantage of the thermic effect of food - calories burned by processing of nutrients - more often, leading to a leaner physique.  But does this hold true?

A recent study from the British Journal of Medicine seems to indicate that it does not.  In the study, a group of individuals all followed a diet with the same degree of caloric deficit.  The difference was that half of the individuals consumed six smaller meals per day, while the other half consumed three larger ones.  At the end of eight weeks, researchers found that both groups experienced significant decreases in weight, fat mass and BMI.  But contrary to the belief of many dieters, the plan with more frequent meals did not induce greater weight or fat loss or superior control of appetite.  In other words - for dieters, meal frequency appears to be irrelevant.

This is great news for those who don’t like packing snacks to eat on the go and those who prefer larger meals.  However, it doesn’t mean eating smaller, more frequent meals is bad - whatever works for the individual is best.

SOURCE:

Cameron JD, Cyr MJ, Doucet E. Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. British Journal of Medicine, 2009; Nov 30:1-4

One supplement that many people consider using at one point in their training career is Yohimbe.  It comes from the bark of a tree that grows primarily in West Africa and is included in many of the fat loss or performance enhancing products you may be looking at.

How effective is yohimbe?

One study that was conducted out of the Institute of Sports Medicine in Serbia wanted to look at the effects this supplement had on the body composition as well as the exercise performance of professional soccer players.

The design of the study was such that 20 top level male soccer players were divided into two different test groups. The first group orally ingested yohimbine tables that contained a dose of 20 milligrams per day divided up across two different doses.

These subjects proceeded to take this dose for a total of 21 days while those who were in the placebo group took in an equal number of identical looking pills that contained no dose, just cellulose. This disregarded any benefits of the mind with regards to performance enhancement as neither group knew which pill they were using.

The researchers noted after the 21 days had passed that there was no significant body mass changes between the groups however the group that took the yohimbe did notice a significant decrease in body fat compared with the placebo.  In addition to this, the raw total body fat measurement did go down clearly indicating that there were favourable body composition changes taking place.

Exercise performance did not change significantly however and neither group reported feeling any side effects from the pills.

Therefore, from this study we can conclude that if you are looking to reduce body fat, yohimbe can be a very effective aid.  You may not want to rely on it strictly for performance enhancements, but in many cases if you’re a competitive athlete the lower body fat you do have, the better your performance will be due to less body weight to transport throughout the activity.

Indirectly then, this supplement could potentially improve your performance through the reduction of overall fat mass.

Reference:

Ostojic, SM. (2006). Yohimbe: the effects on body composition and exercise performance in soccer players.  Institute of Sports Medicine, Sports Academy, Belgrade, Serbia and Montengro. Dec;14(4):289-99.

Despite the amazing advances in knowledge and technology, some prefer to stick to the classics.  This trend is constantly being illustrated over and over in the world of medicine, where some prefer "traditional herbs" and "ancient remedies" to more modern treatments.  And though some are skeptical of such inclinations, there’s a very good reason to stick with these traditional remedies - they work, and have been for thousands of years.  If a natural remedy is still going strong and providing results comparable to even the latest technological breakthroughs, why opt for something different?

One notable natural remedy that traces its origins nearly back to the origins of man is Ginkgo Biloba.  This natural supplement is taken from the Ginkgo tree, which is one of the oldest species of trees, tracing its roots back 150 to 200 million years.  The Chinese are believed to be the first culture to tap the therapeutic benefits of Ginkgo, while Europeans didn’t experience the ingredient until the 1700s.  Despite the long history, though, Ginkgo Biloba is still in use today for a variety of ailments.

Ginkgo Biloba is commonly used to treat respiratory issues, such as asthma and lung congestion.  In addition, it can improve blood flow and is used to aid alertness, mental energy, memory and to promote longevity.  Ginkgo Biloba is also very important for active individuals, as it has potent antioxidant benefits.  Antioxidants scavenge free radicals, which are released in large numbers during exercise and can damage the body if left unchecked.  Additionally, Ginkgo Biloba increases the efficiency of one’s metabolism and boosts blood circulation to the brain and through the rest of the body.  This ensures that working muscles receive the nutrients they need, allowing for peak performance.

Still, some athletes may view Ginkgo Biloba as more of a general health supplement, and not one that can really enhance their efforts in the gym.  Sadly, they’d be mistaken.  New research suggests that Gingko Biloba can actually have an anabolic (muscle-building) effect.  A recent study analyzed the effects of Ginkgo Biloba supplementation on ageing muscles by comparing a supplement group and a control group over the course of 60 days.

At the end of the time span, the researchers found that the Ginkgo group developed less fat, had more muscle tissue and demonstrated superior muscle power.  The Ginkgo supplementation also reduced concentrations of creatine kinase, an indicator of muscle damage, in the blood.

Sometimes, it seems, an old supplement can learn new tricks. While Ginkgo isn’t going to make you huge overnight, it can still benefit your muscle-building efforts.

SOURCE:

Bidon, C., et al. The extract of Ginkgo biloba EGb 761 reactivates a juvenile profile in the skeletal muscle of sarcopenic rats by transcriptional reprogramming. PLoS One, 2009: 4(11):e7998.

One of the most well known supplements on the market to improve sports performance and give you an added energy boost is caffeine.  Many athletes are starting to get in the habit of using caffeine regularly, whether it’s through drinking a cup each day in the morning or using a supplement a short period of time before they head out for a hard workout.

The International Society of Sports Nutrition recently posted their stand on the issue of caffeine use for athletic performance and had some important findings to report on.

First they stated that caffeine is effective for boosting your sports performance when consumed in moderate dosages of between 3 and 6 mg per kilogram of body weight.  They also noted that further intake beyond these levels will not increase performance any more so there is no point in really increasing your intake beyond this.  Since caffeine is an addictive substance for people, you should always practice moderation when use or you may find that you are unable to sustain athletic exercise without it.

It was also found in their research that caffeine taken in supplement form does show higher levels of benefits than when it is consumed through coffee, further providing more evidence why you should consider supplemental form.  Many individuals also find it very difficult to perform their usual exercise after coffee consumption, so pill form does tend to be superior.

The study reported that caffeine use appears to be especially beneficial in intermittent activity such as the sports of soccer and rugby where you are going hard for a very brief moment and then taking more time to relax.

Finally, they also reported that caffeine is beneficial for use with both endurance and higher intensity exercise, so regardless of what your chosen activity is, this is a supplement that works across many levels

So next time you’re looking to boost your performance, be sure to keep caffeine in mind.  You may think you’re getting all the benefits from having your daily coffee, but to really ramp up performance and see increased energy, opt for a supplement form.

You can find caffeine in straight pill form or you can get it combined with other ingredients for a higher level of benefits.

Reference:
Campbell, B. et al. (2010). International Society of Sports Nutrition Position Stand: Caffeine and Performance. Journal of International Society of Sports Nutrition. Jan 27.

Without a doubt, one of the hottest (no pun intended) topics in the realm of physical fitness and nutrition is fat burning.  Spend just a few minutes in front of a television, and no matter what the channel, you’re bound to be subjected to at least one commercial for a lean, mean, gut-reducing diet plan or "revolutionary" piece of fitness equipment that will allow you to torch calories with little to no effort.  And you’ll most likely also catch an advertisement or two for some miracle supplement that will expose your six pack in no time.  If only it were that easy.

However, that’s not to say that supplements can’t help one’s attempts to shed weight, burn fat and fit into a slimmer pant size.  But no supplement or exercise equipment will do all the work for you; some effort is involved, and the more work you put in, the more you will get out.  Any diet plan relies on a caloric deficit to be effective, and the best way to ensure that more calories are expended than are taken in is to exercise more and eat less.  Only then can supplementation do its job - supplement a well-designed and well-implemented program to improve results.

In world of fat burning supplements, the debate over the most effective ingredient is nearly impossible to settle.  Countless substances have been proven effective in a number of studies, and individuals often have their preferred set of ingredients, those that promote the best progress.  Some of the more popular ingredients are caffeine, green tea extract, geranium extract, yohimbe and white willow bark, though there are many others that are considered powerful thermogenics and more often than not, ergogenic (energy-boosting) aids as well.  Unfortunately, most research has involved one substance at a time, and the question of which fat burner is most effective has remained unsettled.  Until now.

That’s because a recent study from the British Journal of Nutrition has uncovered a potent new combination: caffeine and EGCG, a powerful antioxidant usually extracted from green tea.  Each of these has been shown to boost metabolism independently, but the British Journal of Nutrition paired the two and found some very impressive results.  The researchers found that the combination of 200mg of caffeine and 400mg of EGCG, when supplemented three times daily, would cause one to burn 180 calories more per day than the placebo group, and this was not including exercise.  Given the ergogenic nature of the two supplements, it’s not hard to imagine that one would have the extra motivation needed to get an intense workout in as well.

So rather than argue over which supplement is best on its own, take a cue from the results of this study and combine caffeine and ECGC for maximum benefits.

SOURCE:

Bérubé-Parent S, Pelletier C, Doré J, Tremblay A. Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men. British Journal of Medicine; 94(3):432-436.

Delayed onset of muscle soreness is something that many of those training experience.  Regardless of whether you are a heavily trained athlete or a recreational exerciser just starting out, there will come a time when you’ll roll out of bed and notice you have a strange inability to walk.  This is what is commonly referred to as DOMS.

As a result of this soreness, many people mistakenly begin to believe that it is a necessary factor to indicate you have had an effective workout.  This is not the case, however, as DOMS can and will occur for numerous reasons such as exercise selection, nutritional intake prior to and after the exercise session, degree of training status, and the amount of rest given.

Many treatment methods for DOMS have been established to help make this tender period lower in duration.  Recently a study was published by the School of Community Health and Sports Studies looking at the causes of DOMS and the most effective management protocol.  

Anti-inflammatory drugs have shown to have some positive impacts on recovery depending on when they are administered. Massage also can prove to be helpful however shows variable results that really depend on the type of massage given and who is administering it.  

Often thought to help but proven quite ineffective treatment methods include cryotherapy, stretching, homeopathy, as well as ultrasound or electrical current stimulators. Some people will attempt to use these but with very little success.

Interestingly, and contrary to what most individuals would think, exercise proves to be one of the most effective ways of relieving DOMS.  It’s important to note though that often with exercise, the pain may return later on the day, so while short-lived, it can make the natural recovery process that much easier.

When using exercise as a means to help recover from DOMS, it’s encouraged to reduce the total intensity and length of the exercise for a couple of days following the original onset and those body parts that are least sore should be the primary ones focused on.  You should also avoid introducing any new movement patterns during a recovery period of DOMS because often the
soreness is most noticeable when new exercise is completed.

So next time you find that you’re feeling pretty tender, don’t take that as a signal to completely back off exercise.  Some lighter exercise can help with the recovery process and allow you to feel better. Just be sure you don’t try and push the tender muscles too hard or you may put yourself at risk for injury.

Reference:
Cheung, K., Hume, P., Maxwell, L. (2003). Delayed onset muscle soreness: treatment strategies and performance factors.  Sports Medicine. 33(2):145-64.

Like a bitter three-way sibling rivalry, it often seems that the three main macronutrients - carbohydrates, protein and lipids (fats) - are constantly battling for supremacy. Nutritional experts and those merely passionate about food ceaselessly compare and contrast the three in terms of taste and dietary value.  Each macronutrient has its delicious offerings as well as important functional purposes in the body, so it’s nearly impossible to pick out one that is indisputably the best.  But in terms of fitness and optimal health, whether one is attempting to shed fat or gain muscle, the one macronutrient that tends to get the most positive attention is protein.

This is because protein is a triple threat in the battle to build a better physique.  Protein has a variety of benefits that will be appreciated no matter what direction one is attempting to move the scale.  Dieters will be pleased to find that protein increases feelings of satiety and provides an energy boost, so one will be less likely to fall into an afternoon slump and try to remedy the situation by snacking.  Those looking to gain muscle will benefit from the amino acids in protein, which are the building blocks of muscle.  And both groups will benefit from the fact that protein has a high thermic effect, meaning that the body needs to expend a lot of energy to process protein, which can cut down on unwanted body fat.

And those taking in a significant amount of protein tend to do so in the post-workout period - widely believed to be the most important time to consume protein in order to reverse muscle breakdown and initiate muscle building.  But what many people might not realize is that taking in protein pre-workout can be beneficial as well.  In fact, a new study indicated that there is at least one significant benefit - increased metabolic rate.

In the study, subjects were given either a carbohydrate-heavy supplement (1 gram fat, 18 grams carbohydrate, 1 gram protein) or a protein-heavy supplement (1.5 grams fat, 2 grams carbohydrate, 18 grams protein) before a resistance training session.  One might assume that the carbohydrate-heavy supplement would be preferable, as carbohydrates are the body’s preferred source of energy.  However, the study indicated that for those looking to improve body composition, protein was the better choice.

The results of the study showed that the day after the exercise session, the protein-supplement resulted in an 8.5 percent increase in resting energy expenditure, while the carbohydrate supplement resulted in only a 3.5 percent increase.  So if you’re looking to boost fat-burning even the day after exercise, prioritize protein in your pre-workout meal.

SOURCES:

1. Hackney KJ, Bruenger AJ, Lemmer JT. Timing Protein Intake Increases Energy Expenditure 24 Hours Post-Resistance Training. Medicine and Science in Sports and Exercise, 2009; Dec. 4.

It’s very well known that supplementing with protein powder around the workout period helps to increase the rate of protein synthesis in the muscle and speed up the recovery process. Combining this with a form of simple sugar is even more beneficial because then you will get the insulin response from the glucose that helps to take up these amino acids right into the blood stream almost immediately.

One study that was published in the Endocrinology and Metabolism assessed what the difference in effect would be if you consumed the whey protein before the workout or after the workout.  They had one group ingest a solution of whey protein immediately before the exercise period and then another group of subjects ingest the same whey protein beverage immediately
after the workout period was ended.

The workout consisted of 10 sets of 8 reps of leg extension and phenylalanine concentrations were measured in arteriovenous samples to determine the balance across the leg.

The results of the study indicated that the amino acid concentrations were increased by 50% after taking protein at either time and in both subject groups, the net amino acid balanced switched from being negative to positive.

Additionally, the uptake of the amino acids was not significantly different between either trial period, indicating that having your protein before or after the workout will be beneficial in terms of muscle building and for recovery purposes.

So the take-home message of this study is that if you are on a limited budget in terms of purchasing supplements and protein powder, you will benefit from its use either before or after the workout with one not being all that much more superior to the other.  

It will still, however, likely be most advantageous to taking it before and after if you can simply for the fact that you will have a higher influx of amino acids to the tissues, so more will be available if needed.  Remember that your daily protein intakes must be met to stay in a positive nitrogen balance overall, and since you’ll have the insulin-glucose reaction before and after the workout along with the benefit of exercise on muscle uptake, it would make sense to really focus on a good protein intake at these time periods.

Reference:
Aarsland, A.A. (2006). Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise.  American Journal of Physiology and Endocrinology Metabolism.

This particular placebo controlled study compared carbohydrate versus whey protein, looking at force contraction recovery time at the neuromuscular junction.  This was quite an unusual design, having ten male subject’s complete three treadmill walks lasting 2 hours and carrying a 25kg backpack and measuring the force of isometric or isokenetic contractions. During these tests, subjects were either drinking the carbohydrate solution, whey protein or placebo.  For three days after the tests, the subjects continued to ingest of the three concoctions.  Muscle performance was measured pre- test and at time points 0,24,48 and 72 hours after the test had been completed.  The researchers found  when measuring force production, utilizing isometric contractions,  both the carbohydrate solution and whey protein  improved the recovery of neuromuscular function at the 48 hour mark, where are the placebo group, didn’t improve back to pre-exercise values until 72 hours.  None of the groups improved performance when testing isokinetic contractions.

Sam D Blacker, Neil C Williams, Joanne L Fallowfield, James LJ Bilzon and Mark ET Willems
Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage
Journal of the International Society of Sports Nutrition 2010, 7:2doi:10.1186/1550-2783-7-2
Published:12 January 2010

Written by: ATHLETIC EDGE NUTRITION

With so much nutritional information available today, there are often conflicting views on what food and drink choices are best for you.  Part of this is because there are so many aspects to take into consideration - bone health, immunity, obesity, for example.  But another issue is that despite the wealth of information, surprisingly little of it has been backed by solid research.

For example, the debate between soy and dairy as a source of protein in one’s diet is an issue that has been discussed quite a lot in recent years.  Each seems to have its unique advantages and disadvantages, although some of these "facts" seem to be backed by little more than opinion and rumor - such as the belief that soy will dramatically raise estrogen levels in men, or that dairy will inevitably make one fat.  And while some of these debates remain contested, researchers recently closed the case on one area conflict - which source of protein is better for improving inflammation and oxidative stress.

According to a study published in the latest edition of the American Journal of Clinical Nutrition, a diet rich in dairy can reduce compounds that cause oxidative stress in the body by more than 20 percent.  Oxidative stress can lead to cell damage, even affecting one’s cellular DNA.  In addition, the researchers found that prioritizing consumption of dairy can lead to lower levels of inflammatory markers - such as indications of future tumor growth - by up to 15 percent.

But dairy wasn’t just slightly better than soy in improving these conditions; the difference was quite significant.  The blinded, randomized crossover study split participants into two groups: one receiving a soy-rich diet, and one receiving a dairy rich diet for 28 days.  After the first 28 days, there was a 28 day "washout" period, and then the groups switched to the other dietary protocol for the next 28 days.  Both diets were identical in terms of calorie content.

Despite the similarities though, the soy-rich diet failed to produce any changes in the inflammation markers or oxidative stress compounds.  Meanwhile, the positive effects of the dairy diet occurred across a wide range of participants, regardless of weight and age (1).

This study is the latest in a vast body of research suggesting that dairy is an important part of one’s diet.  Past studies have shown that dairy performs better as a sports recovery drink than so-called sports beverages such as Gatorade (2), and also that a dairy-rich diet can increase one’s feelings of fullness and metabolic rate (3).  All of this begs the age-old question: Got Milk?

SOURCES:

1. Zemel, M; Sun, M; Sobhani, T; Wilson, B. Effects of dairy compared with soy on oxidative and inflammatory stress in overweight and obese subjects. American Journal of Clinical Nutrition, 2009; 10.3945

2. Cockburn, Emma et al. Acute Milk-Based Protein-CHO Supplementation Attenuates Exercise-Induced Muscle Damage. Applied Physiology, Nutrition and Metabolism, 2008; 33: 775-783

3. Hochstenbach-Waelen, Ananda et al. Comparison of Two Diets with either 25% or 10% Energy as Casein on Energy Expenditure, Substrate Balance, and Appetite Profile. American Journal of Clinical Nutrition, 2009; 89: 1-8

Making the most out of your training program is something that every single one of us going to the gym is aiming to accomplish.  

For many of those who are intensely involved in their training, this also means that they must take performance measures into account and all the variability’s that can impact performance values.

One such value that’s often looked at, especially in higher level athletes who will be travelling for various events, is that of altitude.

Recently a study was conducted out of the Research Center of Health in Japan that assessed the substrate utilization during different elevation training as well as the impact it had on the hormonal profile of the exercising individuals.

The researchers had a group of seven men participate in the study and these men performed sub-maximal exercise sessions at both sea level and at a moderate altitude of 2000 meters as well as a maximal exercise session at each altitude to measure peak oxygen consumption.  

Values were assessed before exercise, during exercise, as well as during the post-recovery period at 15, 30, 45, and 60 minute intervals.

The researchers noted that when the subjects performed the exercise at the moderate altitude level, the respiratory exchange ratio was higher, indicating a great reliance on carbohydrate utilization than at sea level.

In addition to this, epinephrine and norepinephrine concentrations were also elevated in altitude training while free fatty acids and glycerol concentrations during recovery were lower after the moderate altitude sessions.

From this study we can conclude that if you are training at a higher altitude level, you should expect your body to use a greater
reliance on carbohydrates as a primary fuel source and may want to adjust your diet to accommodate this.

If you’re an athlete who is training for competition at sea level and using a lower carbohydrate diet hence will be going into exercise at higher altitude already slightly depleted, you may find a sharp decline in performance or at the very least, a much greater sensation of muscular fatigue when performing the exercise at the elevation.  Consuming more carbohydrates in the days prior to exercising at higher altitudes should help your body prepare for the changes in substrate utilization and ensure that you can maintain your performance level to your best ability.

Reference:
Goto, K. et al. (2009). Substrate utilization during exercise and recovery at moderate altitude. Metabolism. Dec. 24.

Even though gaining quality lean muscle mass is a challenge for many people, the main principles of the effort aren’t really a mystery. The first rule of muscle building, no matter what age or experience level the trainee may be, is that adequate calories must be consumed. But this doesn’t just mean taking a bigger piece of pie for dessert and hoping for the best. Rather, one must ensure first that maintenance levels are met. In addition, extra food must be consumed to fuel a grueling weight training session. And lastly, a few hundred extra calories should be consumed on top of that to guarantee that muscles have enough energy for repair, recovery and growth.

Secondly, another not-so-secret element of strength and muscle gain is consuming adequate levels of protein. While the body can do amazing things and glean energy from any macronutrient (carbohydrates, protein, fat and alcohol) depending on availability, protein is unique in that it is the only macronutrient that can be used to build muscle. This is because it is the only one of these substances that carries amino acids, which are the building blocks of muscle. Without adequate protein intake, your efforts in the gym will not be maximized - and who wants to waste time?

Finally, another common way to optimize your efforts is through the use of creatine. This supplement is widely used due to its safety and effectiveness. Additionally, creatine is a natural supplement, as relatively low levels of the substance are found in meats and the body actually produces some creatine on its own. Creatine is used in the production of cellular energy, forming an integral part of the phosphagen system. This allows for increases in work capacity and strength. A second effect of creatine is that it draws water into muscle cells, making them appear fuller and larger.

Though those benefits of creatine have been established for a long time, new research recently pointed to another advantage of this no-so-secret weight-training weapon - increasing dihydrotestosterone, or DHT, levels in users. In fact, in just one week, supplementation of creatine increased DHT levels by 56 percent; further study found that the rate of DHT increase was positively correlated with the size of the creatine dose. This is quite significant, as the researchers noted earlier studies "indicate that DHT is 4 times more biologically potent than testosterone" (1). And for those unaware -testosterone is the primary male hormone, responsible for muscle growth among many other functions. So in other words, in addition to creatine’s own strength-boosting mechanisms, it can initiate increased DHT levels, spurring more muscle gain.

At a time when there is a lot of pressure to become bigger, faster and stronger - both from society and strength athletes themselves - this is great news. The identification of this substantial benefit of creatine provides a safe, cost-effective option for those who want to achieve extraordinary results without delving into potentially dangerous substances. And unlike many other supplements, creatine is not a laboratory-produced, synthetic drug - it is a natural substance already present in the human body.

SOURCE:

1. van der Merwe J, Brooks NE, Myburgh KH. Clinical Journal of Sports Medicine, 2009; 19(5):399-404.