Rate of force development as a measure of muscle damage
John Wiley & Sons Ltd
Faculty of Health, Engineering and Science
School of Exercise and Health Sciences/Centre for Exercise and Sports Science Research
This study tested the hypothesis that rate of force development (RFD) would be a more sensitive indirect marker of muscle damage than maximum voluntary isometric contraction (MVC) peak torque. Ten men performed one concentric cycling and two eccentric cycling (ECC1, ECC2) bouts for 30min at 60% of maximal concentric power output with 2 weeks between bouts. MVC peak torque, RFD, and vastus lateralis electromyogram amplitude and mean frequency were measured during a knee extensor MVC before, immediately after and 1-2 days after each bout. The magnitude of decrease in MVC peak torque after exercise was greater (P<0.05) for ECC1 (11-25%) than concentric cycling (2-12%) and ECC2 (0-16%). Peak RFD and RFD from 0-30ms, 0-50ms, 0-100ms, to 0-200ms decreased (P<0.05) immediately after all cycling bouts without significant differences between bouts, but RFD at 100-200ms interval (RFD100-200) decreased (P<0.05) at all time points after ECC1 (24-32%) and immediately after ECC2 (23%), but did not change after CONC. The magnitude of decrease in RFD100-200 was 7-19% greater than that of MVC peak torque after ECC1 (P<0.05). It is concluded that RFD100-200 is a more specific and sensitive indirect marker of eccentric exercise-induced muscle damage than MVC peak torque.