Sipilä S, Suominen H
Department of Health Sciences, University of Jyväskylä, Finland.
Muscle Nerve. 1991 Jun;14(6):527-33. doi: 10.1002/mus.880140607.
Ultrasound (US) technique was applied to measure the thickness, cross-sectional area (CSA), and internal structure of the quadriceps muscle in 70- to 80-year-old endurance and power athletes and untrained men. Isometric knee extension strength was higher in the power athletes than in the other groups. The mean values for thickness and CSA did not differ between the athletes and the untrained men. The intensity of the intramuscular echo was, however, lower and the echo reflected from the connective tissue septa and bone was higher in the athletes than in the untrained men. Both the CSA and internal structure of the muscle group correlated significantly with muscle strength and number of training kilometers per year. The results suggest that long-term training maintains the muscle architecture and counteracts the age-related replacement of contractile tissue by other tissues such as fat.
采用超声（US）技术测量了70至80岁的耐力和力量运动员以及未经训练男性的股四头肌厚度、横截面积（CSA）和内部结构。力量运动员的等长伸膝力量高于其他组。运动员和未经训练男性之间的厚度和CSA平均值没有差异。然而，运动员肌肉内回声强度较低，结缔组织间隔和骨骼反射的回声高于未经训练的男性。肌肉群的CSA和内部结构均与肌肉力量和每年训练公里数显著相关。结果表明，长期训练可维持肌肉结构，并抵消与年龄相关的收缩组织被脂肪等其他组织替代的现象。
