Reference
Chen N, He X, Feng Y, Feng Y, Ainsworth BE, Liu Y. Effects of resistance training in healthy older people with sarcopenia: a systematic review and meta-analysis of randomized controlled trails. Eur Rev Aging Phys Act. 2021;18(1):23.
Study Objective
To analyze the existing evidence for resistive exercise training on muscle strength, muscle performance, and body composition in healthy older people with sarcopenia at baseline
Design
A meta-analysis of randomized controlled trials (RCTs)
Participants
Participants included 561 adults (aged >60 years) with sarcopenia in 14 RCTs that were published between January 2010 and October 2020. All the studies included at least 1 type of resistive exercise with 292 (52%) of the participants receiving more than 1 mode of resistance training. Seven RCTs included both genders, 6 included only females, and 1 had no sex listed.
Exclusion criteria included pre-existing conditions (eg, cancer, chronic obstructive pulmonary disease [COPD], diabetes, osteoporosis), articles that were not in English or Chinese, articles without a control group, and those that did not include all outcome parameters (below).
Study Parameters Assessed
The following outcomes were necessary for inclusion in this meta-analysis:
- Body composition (skeletal muscle mass [SMM], leg lean muscle mass [LMM], appendicular skeletal muscle index (ASMI), and body fat mass [BFM])
- Muscle strength (knee extensor strength [KES] and hand grip strength [HGS])
- Muscle performance (gait speed [GS] and timed up and go [TUG])
Investigators assessed various resistance training exercises and body metrics, depending on the RCT. The studies also varied in which body parts they assessed and under which parameters.
Each RCT had a degree of intensity applied to each exercise as well as repetition amount, making for a wide-ranging meta-analysis. The investigators evaluated the following 3 body metrics for ease of study design, as well as performed a subgroup analysis of those 3 groups, focusing specifically on the factors of age, gender, sarcopenia diagnostic criteria, obesity, intervention duration, frequency, mode, and intensity.
Body composition
Eleven of the RCTs evaluated body composition based on 2 main parameters: muscle mass and body fat mass (BFM). Muscle mass was subdivided into 3 separate groups: skeletal muscle mass (SMM), leg lean muscle mass (LMM), and appendicular skeletal muscle index (ASMI).
Muscle strength
Thirteen of the RCTs evaluated resistance training on muscle strength specifically for hand grip strength (HGS) and knee extensor strength (KES).
Muscle performance
Six of the studies measured grip strength (GS) and the timed up and go (TUG), a test commonly used to assess mobility, walking ability, balance, and fall risk in older adults.1
Key Findings
Regarding body composition, no significant differences were found while comparing resistance training to the control group in the following parameters: SMM alone (P=0.07, I2=0%), LLM alone (P=0.52, I2=0%), and ASMI alone (P=0.35, I2=68%). Significant decreases, however, were discovered when comparing BFM in both resistance training groups compared to control (P=0.0002, I2=0%).
Muscle mass significantly increased in those populations aged >70 years (P=0.0002), female (P=0.02), met the Asian Working Group Sarcopenia (AWGS) diagnostic criteria (P<0.0001), and were normal weight (P=0.004). A greater increase of muscle mass was also observed when the resistance training was completed more than 3 times per week (P=0.007), ≥12 weeks (P=0.008) and using at least 60% 1-rep maximum (1RM) intensity (P=0.003).
In the muscle strength category, HGS (P=0.0005, I2=81%) and KES (P<0.0001, I2=67%) were significantly increased in the resistance training group. However, there was a more significant increase in HGS in the group aged >70 years (P<0.0001), as well as modest significant increases in the female (P=0.005), with AWGS sarcopenia diagnostic criteria (P<0.0001), and obese (P=0.01) populations. When participants completed the resistance training fewer than 3 times per week (P=0.04) or ≥3 times per week (P=0.02), and with a total duration >12 weeks (P=0.04) or ≤12weeks (P=0.03), significant increases in HGS were also observed. HGS had a greater effect when performed as a constant resistance loading training (P=0.0007) and using >60% 1-rep maximum intensity (P<0.0001).
KES on the other hand was significantly increased regardless of subject characteristics: aged >70 years (P<0.0001), ≤70 (P<0.0001), female (P<0.0001), male (P<0.0001), those with other sarcopenia diagnostic criteria (P<0.0001), and those with obesity (P<0.0001).
For muscle performance, GS significantly increased in the resistance training group (P=0.006, I2=89%) and TUG time significantly decreased (P<0.0001, I2 = 23%).
Transparency
This meta-analysis was funded by a special health research project of Shanghai Municipal Health Commission on the Health of Aging, Woman and Children. No author conflicts of interest were disclosed.
Practice Implications
Sarcopenia is a decline of skeletal muscle mass and function and is known to lead to frailty, cachexia, osteoporosis, metabolic syndromes, and ultimately earlier death.2 Some 25% to 45% of older adults, even when healthy, are diagnosed with sarcopenia, which often wreaks havoc on the medical system.3 From a public health perspective, the total annual cost for hospitalizations of patients with sarcopenia is $40.4 billion in the United States, bringing a yearly average cost of $260 per person.4 Older age, female gender, lower education, lower socioeconomic status, being underweight, and lower birth weight are all associated with a higher likelihood of sarcopenia.5
Various therapies have been evaluated for treating sarcopenia, though exercise appears to outperform all others.6 Specialized and easily reproducible exercise programs improve several health markers for sarcopenia patients, leading to improved longevity and quality of life. According to the authors of the study reviewed here, this publication is the first systematic review and meta-analysis aimed to assess resistance training’s effect on older people with sarcopenia. They discovered that several body metrics significantly improved with various forms of resistance training exercise.
They did not, however, assess the effects of nutritional supplementation or diet on sarcopenia, which research suggests can also provide additional benefit. Leucine, creatinine, and other high-quality amino-based metabolites appear to compound beneficial aspects of resistance training in these same older patients.7 So, while resistance training does demonstrate clear value, additional research is needed on a combination of therapies for the most comprehensive approach
