This is the first investigation to provide an extensive isokinetic profile of a knee joint in young basketball players throughout the developmental ages 12 to 17. This study presents values for conventional and functional reciprocal muscle group torque ratios as well as for peak absolute and relative torque at various speeds and muscle actions in young basketball players throughout 12 to 17 years old. Furthermore we document an age-related increase independent of changes in body weight in concentric and eccentric peek torque in young basketball players . In contrast both conventional and functional reciprocal muscle group torque ratios do not change throughout the developmental years 12-17 in young basketball players .