The purpose of this study was to evaluate the relationship between aerobic capacity (VO2peak) and leg strength of male (n = 17) and female (n = 12) youths (age = 14.2 ± 2.1 years) with mild to moderate mental retardation. Aerobic capacity was determined by a treadmill test (GXT) and isokinetic knee flexion and extension strength (peak torque, peak force, average force) was determined by isokinetic dynamometry. Results indicate that significant positive relationships (p < .05) exist between VO2peak (ml · min−1 · kg−1) and isokinetic leg strength expressed relative to body weight. The results indicate that leg strength is a contributor to aerobic fitness in youths with mental retardation. Additionally, when considering the low levels of both strength and VO2peak, leg strength may be a limiting factor of VO2peak in these youths, or the relationship may be explained by the concept of metabolic nonspecialization.
K.H. Pitetti is with the College of Health Professions at Wichita State University, Campus Box 43, Wichita, KS 67260-3060. B. Fernhall is with the Exercise Science Program, School of Medicine and Health Sciences at George Washington University, 817 23rd St. NW, Washington, DC 20052.
Editor’s Note: This article suggests some intriguing concepts regarding possible relationships between muscle strength and aerobic fitness. Several experts in the area of exercise fitness in children have offered to respond to these ideas in a brief commentary at the end of the article. Your written comments addressed to the editor are welcome as well.