Wang Eivind, Nyberg Stian Kwak, Hoff Jan, Zhao Jia, Leivseth Gunnar, Tørhaug Tom, Husby Otto Schnell, Helgerud Jan, Richardson Russell S
Department of Circulation and Medical Imaging, Faculty of Medicine, The Norwegian University of Science and Technology, Trondheim, Norway; Department of Medicine, University of Utah, Salt Lake City, UT, USA; Department of Research and Development, St. Olav's University Hospital, Trondheim, Norway.
Department of Circulation and Medical Imaging, Faculty of Medicine, The Norwegian University of Science and Technology, Trondheim, Norway.
Exp Gerontol. 2017 May;91:64-71. doi: 10.1016/j.exger.2017.02.071. Epub 2017 Feb 21.
Although aging is typically associated with a decreased efficiency of locomotion, somewhat surprisingly, there is also a reduction in the proportion of less efficient fast-twitch Type II skeletal muscle fibers and subsequently a greater propensity for falls. Maximal strength training (MST), with an emphasis on velocity in the concentric phase, improves maximal strength, the rate of force development (RFD), and work efficiency, but the impact on muscle morphology in the elderly is unknown. Therefore we evaluated force production, walking work efficiency, and muscle morphology in 11 old (72±3years) subjects before and after MST of the legs. Additionally, for reference, the MST-induced morphometric changes were compared with 7 old (74±6years) subjects who performed conventional strength training (CST), with focus on hypertrophy, as well as 13 young (24±2years) controls. As expected, MST in the old improved maximal strength (68%), RFD (48%), and work efficiency (12%), restoring each to a level similar to the young. However, of importance, these MST-induced functional changes were accompanied by a significant increase in the size (66%) and shift toward a larger percentage (56%) of Type II skeletal muscle fibers, mirroring the adaptations in the hypertrophy trained old subjects, with muscle composition now being similar to the young. In conclusion, MST can increase both work efficiency and Type II skeletal muscle fiber size and percentage in the elderly, supporting the potential role of MST as a countermeasure to maintain both physical function and fall prevention in this population.
虽然衰老通常与运动效率降低有关，但有点令人惊讶的是，低效的快肌II型骨骼肌纤维比例也会降低，进而导致跌倒倾向增加。最大力量训练（MST），尤其是在向心阶段强调速度，可提高最大力量、力量发展速率（RFD）和工作效率，但对老年人肌肉形态的影响尚不清楚。因此，我们评估了11名老年（72±3岁）受试者在进行腿部MST前后的力量产生、步行工作效率和肌肉形态。此外，作为参考，将MST引起的形态学变化与7名进行传统力量训练（CST，侧重于肥大）的老年（74±6岁）受试者以及13名年轻（24±2岁）对照者进行了比较。正如预期的那样，老年人进行MST可提高最大力量（68%）、RFD（48%）和工作效率（12%），使其恢复到与年轻人相似的水平。然而，重要的是，这些由MST引起的功能变化伴随着II型骨骼肌纤维大小显著增加（66%）以及比例向更大百分比（56%）转变，这与接受肥大训练的老年受试者的适应性变化相似，此时肌肉组成与年轻人相似。总之，MST可提高老年人的工作效率以及II型骨骼肌纤维的大小和比例，支持MST作为维持该人群身体功能和预防跌倒对策的潜在作用。
