The purpose of this study was to clarify the characteristics of muscular strength during isokinetic contraction and the prescription of muscular training of young athletes.
　The subjects were 23 junior high school students (12 male and 11 female track and fielders), 201 senior high school students (38 male and 21 female track and fielders, 13 male and 8 female swimmers, 108 male baseball players and 8 male and 5 female oars) and 70 varsities (35 male and 35 female members of ESCI tennis club).
　The leg extension strength was determined by measuring the peak torque generated through a range of constant angular velocity by use of an isokinetic device (Cybex II, Lumex Inc.).
　The results were summarized as follows;
　1) The peak torque of male students in junior high school, senior high school and university was greater than that of female at a whole range of angular velocities.
　2) Sex difference in peak torque became gradually greater as the athletes growing old.
　3) Baseball players showed the largest peak torque, followed by swimmers and track and fielders.
　4) No apparent difference in peak torque was found between sprinters and jumpers, but the significant differences between distance runners and other track and fielders were observed.
　5) The peak torque in baseball players was the greatest in outfielders, followed by catchers, pitchers and infielders in this order.
　6) The apparent effects of muscular training on peak torque and on its relative value were observed in each angular velocity.

DESCENTE SPORTS SCIENCE Vol.6/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE