Inter sex muscle activation differences

A study recently published in the journal of "Bone and Joint" has aimed to find the differences between males and females in their performance of football kicks, and relate that to the difference in ACL injury rates.

There is existing research which shows that females are more likely to suffer non-contact ACL injuries than males, however no direct cause for this has been established.

The study was carried out at Washington University School of Medicine, and was lead by Dr H Brophy, a former professional footballer.

The study involved 13 male and 12 female college football players. These athletes performed 5 in-step kicks, and 5 side foot kicks each, with their movements being recorded using 10 video cameras, 21 retroflective markers and 16 electrodes. The activation of 7 muscles (iliacus, gluteus maximus, gluteus medius, vastus lateralis, vastus medialis, hamstrings and gastrocnemius) were recorded in both legs, and the activation of 2 muscles (hip adductors and tibialis anterior) were recorded in the kicking leg. Muscle activation was measured as a percentage of maximum voluntary isometric contraction.


The Results

• In the kicking leg, males generated about 4 times as much hip flexor activation as females (123% in males compared to 34% in females).
• In the supporting leg, males generated more than twice as much gluteus medius activation (124% in males compared with 55% in females) and vasteus medialis activation (139% in males compared with 69% in females).
• An interesting observation made during the analysis was that, due to females having less activation of the hip adductors, their hips tend to "collapse" into adduction during the kicking motion, increasing the risk of injury.

Although Brophy states that this study doesn't establish a direct cause and effect relationship between muscle activation, knee alignment and ACL injuries, he did conclude by saying, "Activation of the hip adductors may help protect players against ACL injuries."

There are a number of positive and negative points to consider with this study. The main criticism i have of this study is the lack of information we are given concerning the way in which each kick was carried out (ie. was it carried out with maximal effort to replicate a shot, or an effort level to replicate a pass?). I also feel that the amount of information given concerning the athletes participating in the test is too vague. More knowledge of experience and skill level could affect the way these results are viewed.

There are positives as well though. The size of the study group (13+12) is impressive for a study working in such detail, which suggests reliability in the results. The study was also carried out at a reputable university, which lends to it's credibility.

Overall, i feel that this is a very interesting and important study. Although the results don't confirm a cause and effect relationship, i'm sure this study will act as a stepping-stone to more specific research being carried out in the future. In the mean time, i feel that Dr Brophy's suggesting to place a higher focus on strengthening muscles surrounding the hip should be taken very seriously, especially by females.



Ben Brown

Sports drinks explained

Sports drinks first appeared about 50 years ago, when American college teams began to experiment with them. These colleges found that combining salt, sugar and water aided athletic performance. Athletes experienced a slowing in the rate of dehydration, as well as energy sources being replenished. This allowed athletes to work harder, work for longer and think more clearly.

Today the choice of sports drinks is huge. The basic formula is still there though, with water, carbohydrates and electrolytes making the base. The developments made in sport science have made it possible to calculate what amount of each basic ingredient will be most beneficial to an athlete. It is proven that carbohydrate content must be between 5-8% to be effective, any less than this and it won't be enough to have an effect on performance, any more than this and the body's absorption of water will be impaired.

There is a common misconception that all sports drinks are the same. However, sports drinks can actually be put into three different categories. Each one is designed to suit a different occasion.

Isotonic drinks contain a balance of carbohydrates, electrolytes and water which is the same as in the human body. This can be absorbed at roughly the same speed as water, but has greater calorific value.

Hypotonic drinks have a carbohydrate and electrolyte to water ratio lower than that of the body's. This allows the fluid to be absorbed more quickly, but with less energy replenishment, making this drink suitable for sports where dehydration is likely.

Hypertonic drinks have a greater carbohydrate and electrolyte to water ratio than in the body, meaning the fluid is absorbed the slowest, but the energy replenishment is greatest. This form of drink is most effective when used as a post-exercise recovery drink.

Lucozade, Gatorade and Powerade all come under the category of Hypertonic drinks. It is therefore important to consider what your sport demands before choosing which sports drink to use, as well as which time you are consuming it (pre, during or post sport).



Ben Brown

EPO Abuse

EPO (Erythropoietin) is a hormone produced in the kidneys. Once produced, it travels via the circulation into bone marrow. It is here in the bone marrow where it is used to create red blood cells. 

By increasing the amount of EPO in the body, you also increase the number of red blood cells in circulation. The advantage of this is increased oxygen carrying capacity, which of course has a large effect on endurance performance.

Because EPO is a naturally occurring hormone, it is safe and legal for athletes to boost the levels of this hormone in their body through use of altitude training (real or simulated). However, injections of artificially created EPO are even more effective, making performance boosts of 5% or more possible. There are serious health risks associated with injecting EPO, as the blood becomes much thicker with the increase of red blood cells. The chance of a clot occurring increases as a result of this. In recent years, the death's of 20 cyclists are thought to have been caused by this clotting.

Unsurprisingly, EPO is on the IOC's list of banned substances. Though for many years, it was an extremely difficult substance to test for. The original test protocol used by the UCI was too simplistic to generate clear cut results. This test involved taking a blood sample and measuring the proportion of red blood cells within it. If a high proportion of hematocrit was found, then the athlete would not be banned, but they would not be permitted to compete on the grounds of it being a health risk. It wasn't possible for the UCI to ban an athlete from these results as there was no way of proving the increased hematocrit levels were achieved through altitude training.

One of the other major problems with this test, was that it was very simple for athletes to cheat. The test protocol meant that it was necessary to give athletes a 10 minutes to report to the medical team. Within that 10 minutes it would be possible to inject 500ml of saline into the blood stream, instantly bringing the hematocrit level down by a few percent.

The second form of EPO test is a urine test. This test is much more complex than the previous one, as it is designed to expose artificial EPO from natural EPO, as opposed to just measuring the effect any form of EPO has had on the body. This method, based on the technique of Immunoblotting, was first tested to see if it could detect the use of recombinant (artificial) EPO in patients who were using the drug. It was successful. The same technique was then used to examine 102 frozen urine samples from the 1998 Tour de France. This testing revealed 28 positives. The 14 samples with the highest concentration were then Immunoblotted. All were positive for recombinant EPO, Looking at these results, it would appear likely that at least 20% of competitors in this tour used EPO.

The third form of testing takes an alternative route to the detection of EPO abuse. Instead of looking at the EPO itself, it looks at the effects EPO has on red blood cells. The Australian Institute of Sport (who developed this test) found that a specific indicator of EPO injections is an increase in the of immature red blood cells (reticulo cells). Through analysis of these reticulo cells, it is possible to distinguish between athletes who have injected EPO, and athletes who have had a natural increase in red blood cells.

There are problems with both the urine and blood tests. It is speculated that the urine sample will only test positive if the last injection was carried out a few days before the test. Any more and the EPO will have disappeared from circulation, and therefore urine. The blood test is likely to be capable of detecting EPO use within the previous 2 weeks, as that is the length of time red blood cells take to mature.

So, despite each of these tests displaying frailties which a minority of athletes will take advantage of, it is encouraging to see that there is progression and rapid improvement in these techniques. As the testing methods have become more and more advanced, this minority of athletes appear to have moved onto blood doping, as the difference in red blood cells is much more difficult to detect. However, as testing techniques continue to develop, more and more cheats will be exposed, and (I'd like to think) sport will become cleaner and more transparent.

Ben Brown

The Cost of Extreme Endurance

Ultra-Marathons are running events which exceed 50 miles in distance. These races are aimed at the fittest, most experienced and mentally tough athletes. With such huge distances to cover on foot, injuries such as Tendonitis and Muscle tears are commonplace. However, according to research carried out by Liverpool John Moores University, athletes should have greater awareness and concern over the damage which can occur to the heart during a race.

LJMU studied a group of 25 runners (aged between 24-62) competing in the "Lakeland" race. 16 of the group competed in the 50 mile race, and the remaining 9 in the 100 mile race. All of the runners had at least 2 years of Ultra Marathon experience, and had trained specifically for the race. None of the participants had any known heart conditions. Each of the 25 subjects would be given a blood test, an ECG and would be weighed before and after the race.


The Results:

- Of the 50 mile competitors, the average completion time was 15 hours, and average weight loss was 2kg.

-Of the 100 mile competitors, the average completion time was 36 hours, and average weight loss was 3 kg.

-The post race blood tests showed that Troponin 1 levels rose significantly in 21 of the 25 subjects. In 3 of the runners, levels were high enough to suggest serious Cardiac damage.


The ECGs carried out before the race are said to have shown slow heart rates along with the electrical changes you would expect from an athlete.
In the post-race race ECGs, there were significant electrical changes in over 50% of the subjects. In some of the subjects, bizarre electrical changes were shown, not usually seen in normal ECGs (At rest or during exercise).

In Professor Somauroo's summary of the results, he stated that the study "suggests that running continuously over 50 or 100 miles may not be good for the heart". The closing statement of the study however, states that "There was no proven correlation between the changes in Cardiac Troponin 1 and the ECG changes."

This study appears to show that a large proportion of Ultra Marathon competitors are likely to suffer some degree of Cardiac Damage. It is however, important to consider how the study was carried out to decide how reliable the results are likely to be.


-The study group was small and therefore may not represent the general condition of Ultra Marathon competitors.

-The Lakeland race, where this study was carried out, suffered very difficult weather conditions. This could have affected the results.

-The subjects may have extremely varied levels of experience, as the only information we're given is that all subjects have been competing in Ultra Marathons for at least 2 years.

-The subjects were not given a full medical check-up prior to the race. This could mean that subjects with unknown heart conditions took part in the study and harmed the validity of the research.


It is expected that further data (Heart function levels) concerning this subject will be released at a later date. This data could go towards creating a greater understanding of the effects extreme endurance events have on the body, and how these adverse affects can be minimised.




Ben Brown

Heel-less Running Shoes

The development of new technologies designed to allow athletes to extend their career's to points previously thought to be impossible is rapid. As the average life expectancy increases, the market for sport equipment products designed for people of middle age and beyond has grown too.

One of the main problems for older athletes, is the frequent occurrence of injuries. The development of a new Heel-less running shoe intends to solve that problem, at least for runners.

Most running injuries suffered by older runners can be attributed to poor technique, with Over-Pronation, Supination and Heel-strike being widely accepted as the main causes. Each of these technical issues cause similar problems for the athlete's body, as they place large stresses on joints, tendons and muscles.

Supination or Pronation of the foot in a running stride mean that the landing force cannot be absorbed properly, increasing stress on the bones and joints. Heel-strike creates similar problems for runners, as the large impact force created by landing on the heel travels in a linear fashion directly though the heel bone, fibula and tibia, as well as placing a great strain on the achilles tendon.

Ideally therefore, a runner will land further forward on the shoe, allowing the force to be partially absorbed and spread by the sole, and the foot itself. This means the stress placed upon the joints is reduced.

The Healus running shoe forces the runner to run in this safer, more sustainable style, in much the same way that an insole would force an athlete to become more neutral in their running stride.

The Healus shoe also uses a shock plate to dissipate the force across the whole foot. This is used in combination with a sole constructed using "HelixVA." This material makes the sole more shock absorbant than the sole of a normal running shoe, meaning that the Heel bone is able to decelerate over a greater distance.

So, it would appear that the Healus technology could help athletes lengthen their running career's considerably through the prevention of injury. It is important to consider, however, that this product is still in the development stage, and that it may be long time before it enters production.

If this product can be designed to be as durable as standard running shoes, with the necessary testing to prove that the theory behind the design is correct, then they could have huge potential.

Ben Brown

The safety of AstroTurf

AstroTurf is the playing surface of choice at many schools and sports clubs in England. The surface's popularity can be put down to two main factors, AstroTurf requires less maintenance than natural turf, and is therefore cheaper. AstroTurf is also much more weatherproof than natural turf, making it available for use more of the time.

AstroTurf was first used in a major stadium in 1965, at the Housten Aerodome (Home of the Housten Texans NFL team). This playing surface was the only viable option, as natural turf would receive no sunlight in an indoor stadium. The use of Astroturf in NFL arenas became much more common, following the example of the Housten Aerodome.

There are however, a number of problems associated with the use of this playing surface. The rate of major injuries on AstroTurf is much higher than that of natural turf. The number of minor injuries such as "turf toe" and "turf burn", which are virtually non-existent on natural turf, are very common on this artificial surface.

There are two physical characteristics of AstroTurf which can be used to explain this high injury rate. The coefficient of friction is much higher on this surface than on natural turf. This means that a greater force must be exerted in order to move, explaining the high occurence of turf toe and turf burn.

AstroTurf also has a higher coefficient of restitution. This measurement displays a surfaces ability to absorb force. As a result of AstroTurf being less absorbent than natural turf, the occurance of broken bones and concussions is far more regular when athletes collide with the surface.

According to Dr. Mark Drakes, the first significant study into the effects of AstroTurf on injury showed that more series injuries were experienced by NFL teams on this surface compared to natural turf. The study also showed that (within natural turfs) the injury rate is also significantly higher on poorly maintained surfaces, and that the injuries on these surfaces showed a similar pattern to those found on AstroTurf, especially in cold weather areas.

With AstroTurf gaining popularity with schools, it is important to consider the injuries which may result from playing on this surface. The other options available to schools are to use natural turf, or to use a more technologically advanced artificial surface. However, both of these options come at a higher cost, one which schools and sports clubs in England appear to be unwilling, or unable to pay.

Ben Brown

Missing the point?

In 2005, as Lord Coe presented London's bid for the 2012 Olympic Games it became clear that providing a legacy of facilities, along with boosting participation rates were at the heart of the campaign.

Since 2005 however, England has suffered a deep recession. As a result of this recession, severe budget cuts were made in June of this year. One of the areas to suffer badly as a result of these cuts has been sport. Lord Coe's promises have been left looking particularly hollow as a result of the cuts.

Conservative sport minister Hugh Robertson admitted that the new budget has caused community sport to take "a major hit".

So how exactly has sport been affected?

-The building of new sports facilities for schools, that would have costed £6.05bn was cancelled partway through.
-Huge cuts to the £1bn local authorities spend on sport and recreation anually, all of which is discretionary.
-A £2bn cut to the total budget of the Department for Culture, Media and Sport by 2015.
-£65 million cut by scrapping the plan to provide free swimming for under 16s and over 60s, as well as cancelling the refurbishment of swimming pools.

The London 2012 Olympics are a great opportunity for Britain to catch up with the rest of the world and become more competitive for future World Championships and Olympic games. The Manchester Aquatics centre and Velodrome, left as a legacy from the 2002 Commonwealth Games have already shown how valuable facilities can be in providing community sport, as well as developing world class athletes.

It's a shame then, that the government appears unable to look at the importance of these Olympics in long term development.





Ben Brown