Mode-specific effects of concentric and eccentric isokinetic training of the hamstring muscle at slow angular velocity on the functional hamstrings-to-quadriceps ratio-a randomized trial v1

Background. Previous studies have examined the mode specificity of eccentric and concentric isokinetic training, but reported conflicting results. Few studies reported that eccentric and concentric isokinetic training are mode-specific, i.e., they will increase only the eccentric or concentric strength, respectively. Other studies reported that mode specificity does not exist. Therefore, this study aimed to assess the mode-specific effects of eccentric and concentric isokinetic training of the hamstring muscle at slow angular velocity on eccentric peak torque of the hamstring (PTecc), concentric peak torque of the quadriceps (PTcon), acceleration time of the hamstring (AThams) and quadriceps (ATquad), deceleration time of the hamstring (DThams) and quadriceps (DTquad), time to peak torque of the hamstring (TPThams) and quadriceps (TPTquad), and functional Hamstring-to-Quadriceps ratio (PTecc/PTcon). Subjects.A total of 30 participants were randomly divided into eccentric and concentric groups. Methods. Two groups pretest-posttest experimental design was used. In the eccentric and concentric groups, eccentric and concentric isokinetic training of hamstring muscle was performed respectively, at an angular velocity of 600/sec for 6 weeks duration. PTecc, PTcon, AThams, ATquad, DThams, DTquad, TPThams, TPTquad,and PTecc/PTcon were measured before and after the completion of training.