Effect of Differences in the Exercise Frequency of Young People on Abdominal Strength and Muscle Thickness

Abstract

Differences in the frequency of exercise among individuals increase during adolescence. These individual differences are associated with developmental differences in abdominal muscle groups that are closely related to activities of daily living. We examined the effect of differences in exercise frequency in young people on abdominal strength and muscle thickness. The subjects were 20 young male university athletes who belonged to sports clubs and who exercised >6 days per week for >3 h per day (athlete group: age, 20.1 ± 1.43 years; height, 171.7 ± 6.74 cm; weight, 67.9 ± 10.41 kg) and 20 young university male students who did not habitually exercise (less than twice per week) (nonathlete group: age, 20.1 ± 1.41 years; height, 171.6 ± 5.46 cm; weight, 63.2 ± 8.62 kg). Their physical characteristics (height, weight, and body mass index), abdominal flexion strength, and abdominal muscle thickness (rectus abdominis, external oblique, internal oblique muscles) were measured. Although no significant differences were found in the physical characteristics of either group, abdominal strength and all muscle thickness were significantly greater in the athlete group than that in the nonathlete group. In addition, a relatively high correlation between abdominal strength and muscle thickness was found only in the athlete group (r = 0.73). In conclusion, abdominal strength and muscle thickness were greater in young athletes who frequently exercise compared with that in nonathletes. Abdominal muscle strength increased with increasing abdominal muscle thickness in the athletes but not in the nonathletes.