Effects of One-Year Detraining on Anaerobic Power and Muscle Thickness of Upper and Lower Extremity in Young Male

Abstract

Detraining over several weeks in athlete reduces a thickness of principal skeletal muscle and anaerobic power progressively. Thought these changing in muscle characteristics of the lower extremities during detraining have been relatively well investigated, it is still unclear whether the changing occurs similarly in the upper extremities, and whether the influence on the upper extremities are more or less than on the lower one. PURPOSE: This study was projected to investigate how the detraining of recreational sports for one-year influences anaerobic power and muscle thickness in the upper and lower extremities of young people. METHODS: Five young male subjects (17.8 ± 0.4years, 173.4 ± 4.4 cm, 63.9 ± 4.9 kg,) who had been recreational sports (martial arts, tennis, basketball, baseball) over 10 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 often 5-second bouts of full effort pedaling and cranking with 20-seconds rest. Thickness of 18 muscles were measured by B-mode ultras onograph. RESULTS: After one-year recess of the recreational sports, muscle thickness of the erector spinae, subscapular, quadriceps and gastrocnemius was significantly decreased, and anaerobic power and intermittent peak power of leg-pedaling was also significantly decreased (anaerobic power: 9.2 ± 0.7 to 8.3 ± 0.7 W·kg−1, p <0.01; intermittent peak power: 11.8±0.7to 10.1±1.4 W·kg−1, p <0.05). Both 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 muscle thickness were remarkably decreased in the 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 muscle thickness of the leg is an important fitness factor for young males. This finding may provide valuable information for many people planning a training program to improve anaerobic power after a certain detraining period.