不同運動訓練類型對中老年人骨質密度暨等速肌力之影響

Effects of different types of exercise training on bone mineral density and isokinetic strength in middle-aged and elderly adults

探討24 週三種不同阻力強度與類型的運動訓練介入，對於中老年人在骨質密度（骨密）、身體組成暨低角速度肌力之影響。方法：共有53 位51~70 歲之健康中老年人自願並完成本研究，經前測最大肌力隨機配對分為控制組13 人 （60.8 ± 2.9 歲）、中阻力組14人 （62.0 ± 5.4 歲）、高阻力組13 人 （62.3 ± 3.6 歲） 及整合式運動組13 人 （62.2 ± 4.7歲）；運動組進行持續24 週、每週2 次、每次75 分鐘的漸進式運動訓練課程，包括中阻力組2 組50%1RM （13-15 次） 及高阻力組2 組80% 1RM （8-10 次） 的全身性9 項機械式阻力運動訓練，整合式運動組則從事1 組50% 1RM （13-15 次） 的阻力運動及30 分鐘有氧運動，控制組則維持正常作息不多做額外的運動。四組受試者於實驗前後 （0 週/25 週） 均進行骨密、肌肉量 （雙能X 光分析儀，dual energy X-ray absorptiometry；DEXA） 和上下肢等速肌力 （等速肌力儀，Biodex System） 之評估，並以單因子共變數分析考驗依變項之變化。結果：24 週實驗後，骨密部分：控制組幾乎所有測量部位均呈現下降趨勢，其中腰椎下降至1.7% （各部位平均流失0.85%），運動訓練組則依測量部位與分組不同有相異的適應情形，其中整合運動組在腰椎增加的幅度顯著高於中組力及控制組 （p < .05），中阻力組除股骨頸上升的趨勢外，在手臂、腰椎、全身呈下降，並顯著低於高阻力組 （p < .05）；而高阻力組骨密則各部位均有增加 （+0.2 ~ +1.5%），在手臂、腰椎與全身顯著高於控制與中阻力 （p< .05），腿部則顯著高於控制與整合組 （p < .05），但肌肉量方面：運動組皆於手臂肌肉量 （1.7~ 2.8%） 較控制組 （-0.7 ~ 1.3%） 顯著增加 （p < .05），腿部與全身肌肉改變量四組之間皆沒有差異；肌力部分：上肢在中、高阻力組之肱三頭肌較控制組顯著提升15.5 ~ 26.1% （p< .05），下肢則以腿後腱肌群進步43.4~56.9%最為明顯 （p < .05）；整合運動組於肘關節和膝關節的屈伸的力量與控制組皆沒有顯著差異。結論：24 週不同類型的訓練，對於促進中老年人骨密以高阻力運動最為有效，在對於肌肉量的效益，整合式與阻力式三種運動型態影響的程度相近；但對於等速肌力的效果，則以阻力運動的影響較佳。

To examine the effects of bone mineral density, body composition, and isokinetic strength after 24 weeks of exercise intervention with three different exercise intensities and mode of exercises in middle-aged and elder adults. Methods: 53 healthy volunteers aged 51-70 years were randomly assigned to 4 groups after a pre-maximum strength test (control group, CG, n=13, 60.8 ± 2.9 years；moderate-load resistance group, MRG, n=14, 62.0 ± 5.4years；high-load resistance group, HRG, n=13, 62.3±3.6 years；multi-component exercise group, MEG, n=13, 62.2 ± 4.7 years ). Exercise groups performed 75 minutes of progressive training program of 2 days per week for 24 weeks. Exercises included of total body workout using 9 different resistance training machines, 2 sets of 50%of 1RM (13-15 reps ) for MRG and 2 sets of 80% of 1 RM (8-10 reps) for HRG. MEG performed 1 set of 50 % of 1 RM (13-15 reps) of resistance training and 30 minutes of aerobic exercise. CG was asked to maintain life style as usual without additional exercise or physical activity. The bone mineral density (BMD), muscle mass, and isokinetic strength of upper and lower limbs were measured by dual-energy X-ray absorptiometry and Biodex System 4 PRO before and after training (0/25 weeks). Results: After 24 weeks, the BMD of lumbar spine had decreased 1.7% and decreased of average of 0.85% in CG. The exercise groups had also shown dissimilar adaptation according to different part of body compared to different groups. The lumbar spine for the MEG had increased significantly than the MRG and CG (p < .05). MRG had shown increased in BMD in femoral neck, but arm lumbar and total body were significantly lower than the HRG. The BMD of HRG had increased (+0.2~ +1.5%) for all body parts；arm, lumbar spine and total body were significantly higher than the MRG and CG (p < .05). Muscle mass in exercise group (+1.7~2.8%) improved arm lean mass more than CG (-0.7~1.3%) (p < .05). Triceps strength had increased 15.5~26.1% (p < .05) and hamstring strength had shown significantly increased of 43.4~56.9% than CG. Conclusion: After 24 weeks of training, The high-load resistance training program has positive effects on BMD in middle-aged and elder adults. However, there were similar responded for muscle mass between the three exercise programs. The isokinetic strength benefited greatly by resistance training.