Motor Performance Scores of Volunteer versus Randomly Selected Subjects

The purpose of this study was to compare motor performance scores of volunteer and randomly selected subjects on five different tasks—vertical jump, shuttle run, grip strength, 50-yard dash, and sit-ups. The subjects were 40 male and 40 female high school students and 48 male and 48 female college students. Half of the subjects were students who volunteered for the study; half were randomly chosen through use of a table of random numbers. The results indicated that volunteer subjects scored significantly better than randomly selected subjects on all of the tasks except for the shuttle run at the high school level and the grip strength at the college level. There was a significant interaction between method of subject selection and sex of subject for high school subjects on the sit-ups and for college subjects on the shuttle run. In both cases the female volunteers scored better than the random females, but there was no difference between the scores for the volunteer and random males.