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| February 2006 |
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Focused training recipe for success for black athletes
It is well-known that athletes from Africa are among the world's top long distance athletes. The reasons for their success have been a controversial subject of debate between sport scientists. New research from Stellenbosch University now ascribes the success of black athletes in especially long distance events to their focussed training regimes and principles. That is according to research conducted by physiologist Tertius Kohn, who receives his doctorate degree in Biochemistry from the University of Stellenbosch in December 2006. As part of his thesis, Tertius, a former Matie gymnast, looked at the role that physiological and biochemistry factors play in the characterising and adaptation of skeletal muscle during long distance training. He focused specifically on physical changes and protein expression. He compared the performance of various ethnic groups by grouping thirteen Xhosa and thirteen Caucasian athletes according to their training volume, time over specific distances and preferred racing distance. Biopsies were done on the muscle tissue of these paired athletes. Tertius looked at the volume of red fibre cells (which is preferred for long distance athletes), intermediate fibre cells (for good middle distance performances) and white fibre cells (ideal for shorter distance athletes), as well as hybrid fibres that fall between these groups. He found that the percentage of hybrid fibres co-expressing fast-glycolytic and fast-oxidative properties decreased with increased training (>50km/wk) and preferred racing distance (>8km) with all athletes in his training group. He also tested these findings against the results of non-athletes. Although most black long distance runners are shorter and weigh less (possible genetic characteristics) it was found that they only differ in three factors compared to white athletes. During sub-maximal tests it was found that black athletes produce less lactate in their blood. This finding collaborates with similar findings by a Danish research group with which Tertius worked. On a muscular level, it was found that black athletes have more fast-oxidative vessels in their quadriceps muscles, as well as higher lactate dehydrogenase (LDH). LDH is the enzyme responsible for the production of lactate. Interestingly enough, the activity of this enzyme was also higher in the various types of fibres of the black athletes, and therefore not because of the occurrence of higher type IIa fibres. No noteworthy differences between the activities of other enzymes (such as fat metabolism enzymes) were found between athletes from various ethnic groups. After noting that the volume of hybrid fibres correlate with the volume and intensity of training, and that the LDH activity was higher in black athletes, Tertius subjected athletes from various ethnic groups to a six week intensive training session on a treadmill. He found no significant differences in their body functioning. He did, however, discover that the LDH enzyme in the muscle tends to increase after training. Although not significant, it was also shown that the lactate levels dropped after the high intensity training followed by sub-maximal testing. According to his research, it seems that black athletes simply train harder than their fellow athletes, rather than being "born" with extra-special abilities. "The genetic composition of a person can still determine whether or not he or she will become a top athlete, although this seems to play a smaller role than previously thought," Tertius warns. Tertius says that the psychological aspects of why certain athletes take part in sport should also be taken into account. According to Tertius, more debate is needed on the role of hybrid fibres, but he suggests that it might be used to "fine tune" muscle fibres, as well as assist in the transformation process into other fibre types. "Basic fibre types are firstly determined by the genes inherited from you parents. Athletes, however, can change their fibre types to a degree by following the correct training programme," he believes. More information:
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Tertius Kohn's
research was promoted by Prof Kathy Myburgh from the Department of Physiological
Sciences, with Dr Marina Rautenbach of the Department of Biochemistry as
co-promoter.