Effects Of Resistance, Aerobic, Or Combined Exercise On Handgrip Strength

PURPOSE: Handgrip strength (HGS), which decreases with aging, is a powerful predictor of chronic diseases and premature mortality, thus widely used in large observational studies and clinical settings. Although resistance exercise (RE) is considered as the main intervention for maintaining large muscle strength, data on the relative efficacy of RE, compared to aerobic exercise (AE) or combined RE plus AE (CE), on HGS are limited, especially from large and long-term exercise trials. METHODS: This randomized controlled trial enrolled 406 inactive adults (53% women, 35-70 years) with overweight or obesity who were randomly assigned to 1 of 4 groups: RE only (n = 102), AE only (n = 101), CE (n = 101), and no-exercise control (n = 102). All exercise participants were prescribed 1 year of supervised time-matched exercise 3 times/week, 60 min/session (CE with 30 min of each RE and AE) at 50-80% of their maximum intensity. HGS, the average of the maximum values of right and left hands, was measured using a dynamometer. Linear mixed effects models following the intention-to-treat principle were used with age, sex, and baseline HGS as covariates. RESULTS: Overall, 94% participants completed the trial with an 82% average exercise attendance rate. Overall mean (SD) of HGS was 39.2 (11.7) kg, and no group differences were found at baseline. The control group decreased HGS by 3.1% (-1.2 kg, p = 0.03) over 1 year in this clinical trial, which is larger than the common metric of around 1% annual decrease in muscle strength with aging after age 30 from observational studies. All exercise groups maintained HGR without significant change over 1 year (all p > 0.05). Compared to the control, HGR increased in the RE (mean difference [MD] = 1.6, 95% confidence interval [CI]: 0.2 to 3.0, p = 0.03), but not in AE (MD = 0.9, 95% CI: -0.6 to 2.3, p = 0.24) or CE (MD = 1.1, 95% CI: -0.4 to 2.5, p = 0.14), group at 1 year. We also found that only the RE (p < 0.001), but not AE (p = 0.88) or CE (p = 0.39), group increased lean body mass (by DEXA) at 1 year compared to the control. However, in adherent participants with ≥80% exercise attendance rate (n = 313, 77%), all exercise groups showed increased HGR compared to the control (all p < 0.05). CONCLUSIONS: This study suggests that RE training is effective to preserve HGS in adults with overweight or obesity. Supported by NIH Grant R01HL133069 NIH Grant R01HL133069