Anaerobic exercise components during the force-velocity test in sickle cell trait.

Incremental exercise tests have shown no difference in exercise capacity (EC), maximal oxygen uptake (VO2max), and ventilatory threshold (VT) in subjects with sickle cell trait (SCT) when compared to controls with normal hemoglobin (Hb). Nevertheless, during long and strenuous exercise testing, subjects with SCT exhibit comparable EC but lower oxygen uptake (VO2). Consequently, specific metabolic adaptations in subjects with SCT have been suggested during endurance exercise, consisting of a slight "handicap" in oxygen consumption and compensation by the hypothetical development of a higher anaerobic metabolism. The purpose of the present study was to research differences in the anaerobic exercise performance, and the anaerobic exercise metabolism between 9 sedentary black males with SCT and 9 controls with normal Hb. The two groups of subjects were matched for morphological and hematological variables and for aerobic fitness. The subjects were tested using the force-velocity test (FV test) characterized by the repetition of 6-s maximal exercise bouts on a cycle ergometer. The anaerobic exercise performance parameters were peak anaerobic power (PAnP), maximal velocity (V0), and maximal braking force (F0). The anaerobic exercise metabolism parameters were blood lactate concentration at PAnP and peak lactate, and blood lactate kinetics during the FV test and the recovery period. The results indicated no significant difference between the SCT and control groups for PAnP (792.3 +/- 63.3 watts vs 763.8 +/- 52.5 watts), V0 (185.5 +/- 8.9 rev.min-1 vs 173.7 +/- 5.8 rev.min-1), F0 (17.1 +/- 1.2 kg vs 17.2 +/- 1.1 kg), blood lactate concentration at PAnP (5.3 +/- 0.9 mmol.l-1 vs 4.8 +/- 0.4 mmol.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 recovery period. The present study indicated that sedentary subjects with SCT and controls with normal Hb had similar anaerobic exercise performance and similar anaerobic exercise metabolism. It did not confirm the hypothetical higher anaerobic metabolism suggested in subjects with SCT.