Welcome back to This Month in Journals, where we read the latest exercise and sports science and pull out some research that might be of interest to skiers.
* Many skiers build coffee into their pre-race rituals – and it turns out, they should. For decades scientists have been finding that caffeine increases endurance in more mainstream sports like running and cycling. But finally, someone decided to look at caffeine’s effect on skiing.
Published in Medicine and Science in Sports and Exercise online ahead of print, Dr. Hans Stadheim from the Norwegian School of Sports Sciences in Oslo and his team set ten high-level skiers on an 8-kilometer double-pole time trail; each participant did the test twice, one after ingesting caffeine and another time with a placebo. Eight of the ten subjects improved their times after taking caffeine, and overall the times dropped by about a minute and a half. This represented a four percent change.
The researchers are excited about their results because they are the first to test this effect in a primarily arms-based activity; arm and leg muscles differ in both the types of muscle fibers that make them, and the amount of carbohydrates they use to extract different amounts of oxygen during exercise.
The team not only showed that caffeine was beneficial for performance, but also gained some insight into its mechanism. For instance, they found that skiers who had ingested caffeine were able to maintain higher heart rates throughout the test, a difference of about five beats per minute. Skiers were also able to reach higher blood lactate concentrations after taking the caffeine. Finally, questionnaires showed that participants had lower perceived exertion and less pain during tests after taking caffeine.
The size of the benefit gained by caffeine users was impressive, and the authors made sure to frame it as such.
“The improvement of 4% after ingestion of 6 mg · kg-1 CAF observed in the study would most likely effect results in real life XCS competitions,” they wrote. “Actually a reduction of 1:25 min to complete the 8 km C-PT is [analogous to] the time difference between the winner and 12th place in the 2011 World Championships relay… in Oslo.”
Takeaway message? Don’t forget that cuppa joe on race morning!
* Careful, though. A study published in the Scandinavian Journal of Medicine and Science in Sports suggests that the use of nutritional supplements changes people’s attitudes towards what is or isn’t acceptable performance enhancement.
Dr. S.H. Blackhouse of Leeds Metropolitan University asked: are supplements a “Gateway to Doping?” They surveyed over 200 high-level athletes – just under half of whom used nutritional supplements – across 32 sports and received surprisingly honest answers. For example: 22% of the athletes who used supplements admitted to doping, while just six percent of the non-users did the same.
The athletes were also presented with scenarios related to supplements and doping, and asked both what they would do and what they thought others would do. Supplement users had significantly more positive attitudes towards doping, and also were significantly more likely to think that doping was effective and would help them win.
Interestingly, both groups said that they would prefer to compete in an environment where there was no doping. But supplement users perceived a greater pressure to dope, and also gave higher estimates of the percentage of athletes in their sport who were doping.
“Athletes who engage in legal performance-enhancement practices appear to embody an ‘at-risk’ group for transition toward doping,” the authors wrote. “…This common practice may lead to a greater willingness to engage in doping behavior if athletes perceive the benefits of using NS have been fully realized and believe that doping is an effective enhancement method.”
However, while the authors found the correlation between supplement use and propensity towards doping both significant and troubling, they didn’t fully accept the “gateway” mechanism that has been proposed both here and in other drug situations. Indeed, they questioned whether doping chronologically followed supplement use, or whether both were simply a symptom of the same thought process.
The paper’s final discussion touched on two further issues. The true level of doping in sport is unknown: it is certainly higher than WADA’s adverse analytical findings log, which calculates a rate of about two percent. But how much higher is it? Previous studies have found projections ranging from six to 34 percent. The supplement users reported a 22 % doping rate and guessed that was about typical of the athletic population (although estimates ranged widely, with a standard deviation of 23).
This highlights what may be a feedback loop. Regardless of the true level of doping, athletes who perceive doping to be more prevalent may feel more pressure to dope. In this study, the athletes who did not use supplements were either blissfully unaware of the scope of the doping problem, or were more realistic and optimistic than the supplement users. Either way, their perception of a lower rate of doping coincided with feeling less pressure to do so themselves.
Finally, the authors pointed out that some substances, like creatine, are on the line between being considered illegal performance-enhancing drugs and simply nutritional supplements. For athletes who use and believe in supplements, these types of drugs may create confusion and influence their decisions as they move towards the world of doping.
* A quick piece in the British Journal of Sports Medicine aimed to address whether the minimalist footwear craze is all it’s really cracked up to be. Specifically, is running in such “shoes” the same as running barefoot?
Dr. Jason Bonacci led a team that put 22 distance runners through their paces barefoot, and also in minimalist footwear, racing flats, and normal training shoes. Their answer, based on biomechanics, was said best in their title: “Running in a minimalist and lightweight shoe is not the same as running barefoot.”
When the runners were barefoot, they had shorter and quicker strides, even while running at the same speed. There were differences in knee and ankle flex and angles, too, but only between barefoot and “shod” running – not between, say, minimalist footwear (in this case Nike Free 3.0 shoes) and racing flats. When running barefoot, power production shifted from the knee to the ankle. That wasn’t replicated with the Nike Frees.
This is somewhat in contrast to other studies, including one that was published looking at Vibram Fivefingers footwear. But other studies have used recreational runners, where this research team, based on Australia, recruited highly-trained runners. They hypothesized that at that level, running mechanics may be so deeply ingrained into athletes that type of footwear has less of an effect, compared to occasional runners who may change their form considerably based on how their feet hit the ground.
This Month in Journals is our occasional series surveying the world of sports science and trying to extract tidbits of research that might be of interest to the skiing public. Previous editions can be found here: March, February, January, December, October, and September.