OUT OF AFRICA, SOMETHING
Will Hopkins, Physiology and Physical Education, University of Otago, Dunedin, NZ
Sportscience News May-June
The South African Sports Medicine Association (SASMA) holds a combined clinical and scientific meeting for sports physicians, scientists, and other sport support professionals once every two years. I was in South Africa on study leave at the time of the most recent meeting, and I attended as one of the guest speakers.
Sport, sport science, and sports medicine have a high profile in South Africa, so there were plenty of high-quality presentations. Some of the talks were even a bit shifty, paradigm-wise. The title of this article is poached from Tim Noakes's 1996 ACSM Wolffe Memorial Lecture, which will be published about now in Medicine and Science in Sports and Exercise. Tim was asked to repeat this talk for the benefit of SASMA delegates who didn't attend the ACSM meeting. The whole of his talk represented a challenge to prevailing or ailing paradigms.
The talks of interest to sport scientists are summarized below. The abstracts for these and the other talks are published in the South African Journal of Sports Medicine (Volume 4, March 1997). I have included the page number to make it easier for you to get photocopies of the abstracts through library interloan. You can also contact the authors via SASMA's website, which will be launched shortly.
No Increased Risk of Colds
After an Ultramarathon
Looks like we'll have to stop telling our students that long hard exercise increases the risk of upper respiratory-tract infections. In this study, which won the new investigator's award, Mike Kiessig and a team from the Sports Science Institute of South Africa kept track of 96 entrants in the Two Oceans marathon (56 km) two days before and during the nine days after the race. Half of the runners inhaled an anti-inflammatory regularly while the other half inhaled a placebo, all in randomized double-blind fashion. After the race, 40% of the runners on placebo developed symptoms of respiratory infection, compared with 17% in the anti-inflammatory group. But here's the punch line: no athlete with symptoms had a positive bacterial or viral culture. Apparently the extra breathing produced local inflammation in the respiratory tract, but not infection. (Abstract #36, p. 14)
Night Splint Speeds Healing
in Lower-Leg Tendons
Dion Viljoen was the runner-up for the new investigator's prize with this study, performed entirely on his own through his sports medicine clinic. He has developed a splint to hold the foot in a position that keeps injured Achilles and plantar tendons stretched at night. An attempt to compare the effectiveness with a placebo splint in a single-blind fashion was unsuccessful, because the athletes knew the placebo wasn't working and refused to wear it! The real splint meanwhile produced spectacular improvements in function and pain over a two-week period relative to another control group receiving non-steroidal anti-inflammatories. (Abstract #64, p. 21)
How Long Are You Down After
Dion also presented research performed for his Masters degree at the Sports Science Institute. The aim was to see how long performance is impaired following an upper respiratory-tract infection. Runners were given various exercise tests up to six days after they had recovered from signs and symptoms of colds or flu. Four months later they stopped training for the same period as their infection, then underwent the same testing schedule for comparison of the effects of detraining. Performance in an treadmill incremental test was reduced only immediately after the infection, and maximal oxygen consumption was down only for two days after the infection. Muscle strength was not affected. Conclusion: the "tiredness" of an infection reduces endurance performance for a couple of days after the infection has apparently cleared up. (Abstract #63, p. 20)
Cramp Not Related to
Magnesium supplements are being touted by some drug companies as the answer to muscle cramp. The idea is that magnesium ions could compete with calcium to prevent neuromuscular excitation and contraction. As far as I know, a controlled study has not been done. Meanwhile Jeremy Nicol and colleagues at the Sports Science Institute presented a descriptive study showing no evidence for the role of magnesium, other ions, or hydration status, in the incidence or recovery from cramp experienced by 21 runners during the 56-km Two Oceans ultramarathon, in comparison with 23 runners who did not experience cramp. (Abstracts #46, 47, p. 16)
Banned Drug Does Not Enhance
Pseudoephedrine is a component of some medicines that make you feel better when you have a cold. On the grounds that it might work like adrenalin or epinephrine, it's banned. But this report from Hunter Gillies and a team at the Cape Town Medical School showed that if anything performance in a 40-km cycling time trial was down by 1% when cyclists took the drug instead of a placebo. Urinary and blood concentrations of the drug were markedly affected by the exercise. I guess if you took the drug off the banned list, athletes might start megadosing with it. Maybe a limit is needed, like caffeine, but prior exercise would have to be taken into account. (Abstract #48. p. 17)
Applies Only to Highly Trained Athletes?
John Hawley presented research from the Sports Science Institute showing that highly trained cyclists had a reduction in endurance performance when strength training was added to their program. He compared the findings to previous research in which less well-trained athletes improved their endurance performance with strength training. Conclusion: if you are not highly trained, any training stimulus may tickle up the muscles for any kind of exercise; but for highly trained athletes, non-specific training is detrimental. (No abstract was published for this talk.)