RESUMEN
This study investigated the effect of eccentric training on concentric strength of the quadriceps and hamstring muscles. The dominant legs of 43 college-age males were pretested concentrically using the KIN-COM(R) at speeds of 60 and 180 degrees /sec. Twenty-eight treatment subjects trained eccentrically at one of the testing speeds for a period of eight weeks; the remainder served as the control group. Prior to each training session, the subjects gave a subjective evaluation of muscle soreness. Delayed muscle soreness did not affect the subjects' ability to train eccentrically. A concentric posttest was taken to determine any treatment effects. The quadriceps muscle did not show any significant change after eccentric training. Eccentric training at 60 and 180 degrees /sec significantly increased the concentric strength of the hamstrings. Eccentric training does appear to be effective in developing concentric strength in the hamstrings. The speed of eccentric training was not a factor in concentric conditioning. J Orthop Sports Phys Ther 1991;13(5):226-230.