The purposes of rehabilitation after sports injury were to recover the injured muscles, and to maintain the physical fitness level. In rehabilitation program, it is necessary for athletes to set up the standard index for return to sport events. The present study was designed to estimate the standard index of recovery in rehabilitation program.
　Subjects were 57 males and 20 females who are top athletes in Japan. The leg extension strength was measured by Cybex II (60 deg /s). The jumping height and the mechanical power output were measured in vertical jump on the force-plate. There were significant correlations between the leg strength and the results of vertical jump. The standard index in rehabilitation was estimated from the relation between the regression line of the above correlation and the difference of leg strength values of affected/unaffected.
　Furthermore, the standard index was confirmed by longitudinal result during rehabilitation of the subject after ACL operation.

DESCENTE SPORTS SCIENCE Vol.12/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE