Cramer Joel T, Jenkins Nathaniel D M, Mustad Vikkie A, Weir Joseph P
1 University of Nebraska-Lincoln, NE, USA.
2 Abbott Nutrition, Columbus, OH, USA.
J Appl Gerontol. 2017 Jun;36(6):709-732. doi: 10.1177/0733464815584669. Epub 2015 May 5.
This study quantified systematic and intraindividual variability among three repetitions of concentric isokinetic knee extension and flexion tests to determine velocity-related differences in peak torque (PT) and mean power (MP) in healthy elderly (HE) versus sarcopenic and malnourished elderly (SME). In total, 107 HE ( n = 54 men, n = 53 women) and 261 SME ( n = 101 men, n = 160 women) performed three maximal concentric isokinetic knee extension and flexion repetitions at 60°·s and 180°·s. PT for Repetition 3 was lower than Repetitions 1 and 2, while MP for Repetition 1 was lower than Repetitions 2 and 3 in SME. Intraindividual variability among repetitions was correlated with strength, but not age, and was greater in SME, during knee flexion, and at 180°·s. Velocity-related decreases in PT from 60°·s to 180°·s were more pronounced in SME. In summary, (a) the repetition with the highest PT value may be the best indicator of maximal strength, while the average may indicate strength maintenance in SME; (b) intraindividual variability among repetitions reflects functional decrements from HE to SME; and
本研究对健康老年人（HE）与肌肉减少症和营养不良老年人（SME）进行的三次同心等速膝关节伸展和屈曲测试中的系统变异性和个体内变异性进行了量化，以确定峰值扭矩（PT）和平均功率（MP）与速度相关的差异。共有107名健康老年人（54名男性，53名女性）和261名肌肉减少症和营养不良老年人（101名男性，160名女性）在60°·s和180°·s的速度下进行了三次最大同心等速膝关节伸展和屈曲测试。在肌肉减少症和营养不良老年人中，第三次重复测试的PT低于第一次和第二次，而第一次重复测试的MP低于第二次和第三次。重复测试之间的个体内变异性与力量相关，但与年龄无关，并且在肌肉减少症和营养不良老年人、膝关节屈曲过程中以及180°·s时更大。在肌肉减少症和营养不良老年人中，从60°·s到180°·s，PT与速度相关的下降更为明显。总之，（a）PT值最高的重复测试可能是最大力量的最佳指标，而平均值可能表明肌肉减少症和营养不良老年人的力量维持情况；（b）重复测试之间的个体内变异性反映了从健康老年人到肌肉减少症和营养不良老年人的功能减退；并且
