Background

The optimal prescription and precise recommendations of resistance training volume for older adults is unclear in the current literature. In addition, the interactions between resistance training volume and program duration as well as physical health status remain to be determined when assessing physical function, muscle size and hypertrophy and muscle strength adaptations in older adults.

Objectives

This study aimed to determine which resistance training volume is the most effective in improving physical function, lean body mass, lower-limb muscle hypertrophy and strength in older adults. Additionally, we examined whether effects were moderated by intervention duration (i.e. short term, < 20 weeks; medium-to-long term, ≥ 20 weeks) and physical health status (i.e. physically healthy, physically impaired, mixed physically healthy and physically impaired; PROSPERO identifier: CRD42023413209).

Methods

CINAHL, Embase, LILACS, PubMed, Scielo, SPORTDiscus and Web of Science databases were searched up to April 2023. Eligible randomised trials examined the effects of supervised resistance training in older adults (i.e. ≥ 60 years). Resistance training programs were categorised as low (LVRT), moderate (MVRT) and high volume (HVRT) on the basis of terciles of prescribed weekly resistance training volume (i.e. product of frequency, number of exercises and number of sets) for full- and lower-body training. The primary outcomes for this review were physical function measured by fast walking speed, timed up and go and 6-min walking tests; lean body mass and lower-body muscle hypertrophy; and lower-body muscle strength measured by knee extension and leg press one-repetition maximum (1-RM), isometric muscle strength and isokinetic torque. A random-effects network meta-analysis was undertaken to examine the effects of different resistance training volumes on the outcomes of interest.

Results

We included a total of 161 articles describing 151 trials (n = 6306). LVRT was the most effective for improving timed up and go [− 1.20 standardised mean difference (SMD), 95% confidence interval (95% CI): − 1.57 to − 0.82], 6-min walk test (1.03 SMD, 95% CI: 0.33–1.73), lean body mass (0.25 SMD, 95% CI: 0.10–0.40) and muscle hypertrophy (0.40 SMD, 95% CI: 0.25–0.54). Both MVRT and HVRT were the most effective for improving lower-limb strength, while only HVRT was effective in increasing fast walking speed (0.40 SMD, 95% CI: − 0.57 to 0.14). Regarding the moderators, our results were independent of program duration and mainly observed for healthy older adults, while evidence was limited for those who were physically impaired.

Conclusions

A low resistance training volume can substantially improve healthy older adults’ physical function and benefits lean mass and muscle size independently of program duration, while a higher volume seems to be necessary for achieving greater improvements in muscle strength. A low volume of resistance training should be recommended in future exercise guidelines, particularly for physically healthy older adults targeting healthy ageing.

中文翻译：

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阻力训练量对老年人身体机能、瘦体重和下半身肌肉肥大和力量的影响：对 151 项随机试验的系统评价和网络荟萃分析

 背景

在目前的文献中，老年人阻力训练量的最佳处方和精确建议尚不清楚。此外，在评估老年人的身体机能、肌肉大小和肥大以及肌肉力量适应时，阻力训练量和计划持续时间以及身体健康状况之间的相互作用仍有待确定。

 目标

本研究旨在确定哪种阻力训练量对改善老年人的身体机能、瘦体重、下肢肌肉肥大和力量最有效。此外，我们检查了干预持续时间（即短期，< 20 周;中长期，≥ 20 周）和身体健康状况（即身体健康、身体受损、混合身体健康和身体受损;PROSPERO 标识符：CRD42023413209）。

 方法

检索了截至 2023 年 4 月的 CINAHL、Embase、LILACS、PubMed、Scielo、SPORTDiscus 和 Web of Science 数据库。符合条件的随机试验检查了监督阻力训练对老年人（即 ≥ 60 岁）的影响。阻力训练计划根据规定的每周阻力训练量的三分位数（即频率、练习次数和组数的乘积）分为低 （LVRT）、中 （MVRT） 和高容量 （HVRT），用于全身和下半身训练。本综述的主要结局是通过快速步行速度、定时出发和 6 分钟步行测试来测量身体机能;瘦体重和下半身肌肉肥大;以及通过膝关节伸展和腿部推举最大重复次数 （1-RM）、等长肌肉力量和等速扭矩来测量下半身肌肉力量。进行了一项随机效应网络荟萃分析，以检查不同阻力训练量对感兴趣结果的影响。

 结果

我们共纳入了 161 篇文章，描述了 151 项试验 （n = 6306）。LVRT 对改善计时和走动 [-1.20 标准化均数差 （SMD），95% 置信区间 （95% CI）：-1.57 至 -0.82]、6 分钟步行试验（1.03 SMD，95% CI：0.33-1.73）、瘦体重（0.25 SMD，95% CI：0.10-0.40）和肌肉肥大（0.40 SMD，95% CI：0.25-0.54）最有效。MVRT 和 HVRT 对提高下肢力量最有效，而只有 HVRT 对提高快速步行速度有效 （0.40 SMD，95% CI： - 0.57 至 0.14）。关于主持人，我们的结果与项目持续时间无关，主要针对健康的老年人进行观察，而针对身体受损的人的证据有限。

 结论

低阻力训练量可以显着改善健康老年人的身体机能，并有益于瘦体重和肌肉大小，而与计划持续时间无关，而更高的训练量似乎是实现肌肉力量更大改善的必要条件。未来的运动指南应推荐进行少量阻力训练，特别是对于以健康老龄化为目标的身体健康的老年人。