ANAEROBIC EXERCISE COMPONENTS DURING THE FORCE-VELOCITY TEST IN SICKLE-CELL TRAIT

Incremental exercise tests have shown no difference in exercise capaci ty (EC), maximal oxygen uptake (V over dot O(2)max), and ventilatory t hreshold (VT) in subjects with sickle cell trait (SCT) when compared t o controls with normal hemoglobin (Hb). Nevertheless, during long and strenuous exercise resting, subjects with SCT exhibit comparable EC bu t lower oxygen uptake (V over dot O-2). Consequently, specific metabol ic adaptations in subjects with SCT have been suggested during enduran ce exercise, consisting of a slight ''handicap'' in oxygen consumption and compensation by the hypothetical development of a higher anaerobi c metabolism. The purpose of the present study was to research differe nces in the anaerobic exercise performance, and the anaerobic exercise metabolism between 9 sedentary black males with SCT and 9 controls wi th normal Hb. The two groups of subjects were matched for morphologica l and hematological variables and for aerobic fitness. The subjects we re tested using the force-velocity test (FV test) characterized by the repetition of 6-s maximal exercise bouts on a cycle ergometer, The an aerobic exercise performance parameters were peak anaerobic power (PAn P), maximal velocity (V-0), and maximal braking force (F-0). The anaer obic exercise metabolism parameters were blood lactate concentration a t PAnP and peak lactate, and blood lactate kinetics during the FV test and the recovery period. The results indicated no significant differe nce between the SCT and control groups for PAnP (792.3 +/- 63.3 watts vs 763.8 +/- 52.5 watts), V-0 (185.5 +/- 8.9 rev min(-1) vs 173.7 +/- 5.8 rev . min(-1)), F-0 (17.1 +/- 1.2 kg vs 17.2 +/- 1.1 kg), blood la ctate concentration at PAnP (5.3 +/- 0.9 mmol . l(-1) vs 4.8 +/- 0.4 m mol . l(-1)), at peak lactate (7.0 +/- 0.9 mmol . l(-1) vs 6.7 +/- 0.7 mmol . l(-1)), and blood lactate kinetics during the test and the rec overy period. The present study indicated that sedentary subjects with SCT and controls with normal Hb had similar anaerobic exercise perfor mance and similar anaerobic exercise metabolism, It did not confirm th e hypothetical higher anaerobic metabolism suggested in subjects with SCT.