The Changes Of One-year Detraining On Anaerobic Power, Total And Regional Skeletal Muscle Mass In Young Male

Abstract

PURPOSE: The present study investigates the effect of detraining of recreational sports for one-year influences anaerobic power and skeletal muscle mass in the upper and lower extremities of young people. METHODS: Eleven young male subjects (18.6 ± 0.9 years, 174.7 ± 3.9 cm, 68.9 ± 7.4 kg,) who had been recreational sports (martial arts, tennis, basketball, baseball) over 6 years participated in this study. During one-year recess of recreational sports, subjects did not perform any other constant periodical exercise which may affect the result. Two all-out cycle ergometer work tests lasting 30 seconds were used to estimate anaerobic power with leg (pedaling) and arm (cranking) exercises. Loads of the tests were 0.087kp per body weight for pedaling and 0.062kp per body weight for cranking, respectively. Anaerobic power was determined by measuring the highest power output during 30 seconds. Furthermore, peak and mean power in intermittent exercise was determined using a protocol of ten 5-second bouts of full effort pedaling and cranking with 20-seconds rest. Thickness of 18 muscles was measured by B-mode ultrasonograph. Total and regional skeletal muscle mass was predicted by the method of Sanada et al. (Eur J Appl Physiol, 96: 24 - 31, 2006). RESULTS: After one-year recess of the recreational sports, predicted skeletal muscle mass of trunk (14%), thigh (7%), lower leg (24%) and total (12%) was significantly decreased, and anaerobic power and intermittent peak power of leg-pedaling was also significantly decreased (anaerobic power: 8.6 ± 0.8 to 8.2 ± 0.8 W·kg−1, p < 0.05; intermittent peak power: 14.2 ± 1.3 to 12.1 ± 2.1 W·kg−1, p<0.05). Among arm skeletal muscle mass, anaerobic power and intermittent peak power of arm-cranking, on the other hand, did not change. CONCLUSIONS: Results clearly showed that in young male subjects anaerobic power and skeletal muscle mass were remarkably decreased in the trunk and leg but not in the arm by a detraining of recreational sport for one-year. In comparison with the legs, the muscle performance of the arm appears to be conserved during detraining independent of the athletic event, and it suggests that the anaerobic power and skeletal muscle mass of the trunk and leg are an important fitness factor for young males.