Isokinetic strength characteristics of the quadriceps femoris and hamstring muscles in high school students.

The purpose of this study was to determine the isokinetic strength of the quadriceps femoris and hamstring muscles in high school-aged students. Forty-seven 15- to 18-year-old high school volunteers served as subjects. Data were gathered on each subject by a questionnaire, lower extremity musculoskeletal assessment, and isokinetic testing of the two muscle groups at 60 degrees/sec and 180 degrees/sec. This study found no age effect on peak torque and no significant differences in peak torque between dominant and nondominant limbs. Significant differences (p less than .001) occurred between the isokinetic strength of male and female subjects. The average hamstring muscle to quadriceps femoris muscle torque ratio was 57 percent at 60 degrees/sec and 70 percent at 180 degrees/sec. A value of foot pounds of torque per kilogram of body weight was provided as a guideline for clinicians. This investigation supports several findings already reported for other age groups.