Strength and duration for maintenance of muscle volume and bone density during old age

研究了自主性跑步运动对快速老化小鼠骨骼肌和骨骼的影响。运动训练预防了与年龄相关的肌肉纤维萎缩(2002年报告)。此外，运动训练抑制了骨量减少(2002年的报告)，提示运动训练对与年龄相关的肌肉骨骼系统的变化是有效的。50、60和70岁的健康男性接受运动训练，其膝关节的最大自愿收缩和伸展分别为60、80或100%，持续24周。每周测量最大肌力和骨密度。运动训练后，60岁男性的最大肌力高于70岁男性，最大收缩幅度为60%或80%(2001年报告)。相比之下，60岁和70岁男性在100%最大收缩后的最大肌力没有差异(2002年报告)。无论运动训练的类型如何，三组之间的骨密度没有差异(2001年和2002年的报告)。运动训练可以防止与年龄相关的最大肌力下降。相比之下，运动训练并不能阻止骨密度的下降。结论：较大强度的运动训练对肌肉力量有效，但对骨密度无效。

Effects of voluntary running exercise on skeletal muscle and bone in senescence accelerated mouse prone 6 (SAMP6) were investigated. An agerelated atrophy in muscle fibers was prevented by exercise training (report by 2002). In addition, an osteopenia was inhibited by exercise training (report by 2002), It is suggested that exercise training is effective for age-related changes in musculoskeletal systemsFifty-, 60-, and 70-years old healthy men were subjected to exercise training with their 60, 80, or 100% of maximal voluntary knee contraction and extention for 24 weeks. Maximal muscle strength and bone density were measured every week. Maximal muscle strength at 60-years-old men was higher than that at 70-years-old men after exercise training with their 60 or 80% of maximal contraction (report by 2001). In contrast, there was no difference in maximal muscle strength between 60- and 70-years-old men after their 100% of maximal contraction (report by 2002). There was no difference in bone density among three groups, irrespective the type of exercise training (reports by 2001 and 2002). An agerelated decline in maximal muscle strength was prevented by exercise training. In contrast, a decrease in bone density was not prevented by exercise training. It is concluded that exercise training at higher strength is effective for muscle strength, but not for bone density