Muscle Power Versus Strength as a Predictor of Mortality in Middle-Aged and Older Men and Women

Objective: To assess whether muscle power (force times velocity) outperforms strength as a risk indicator and predictor of mortality. Participants and Methods: Anthropometric, clinical and vital status, muscle power, and strength data were assessed in 3889 individuals aged 46 to 75 years (2636 [67.8%] men) who were participants in the CLINIMEX Exercise prospective cohort between February 13, 2001, and October 31, 2022. Study participants were stratified by sex and categorized into 4 groups according to the distribution of the results of relative muscle power and strength (adjusted for body weight) measured, respectively, by handgrip and upper row movement tests. Results: Death rates were 14.2% (373 of 2636) and 8.9% (111 of 1253) for men and women, respectively, during a median (IQR) follow-up of 10.8 years (6.7 to 15.5 years). In multivariable Cox proportional hazards regression analyses, the hazard ratios (95% CIs) for mortality comparing the lowest vs highest categories of relative muscle power were 5.88 (2.28 to 15.17; P<.001) and 6.90 (1.61 to 29.58; P=.009) for men and women, respectively. The corresponding hazard ratios (95% CIs) for relative strength were 1.62 (0.89 to 2.96; P=.11) and 1.71 (0.61 to 4.80; P=.31), respectively. Sex-specific results of risk prediction analyses revealed that improvements in C index provided by relative power over relative strength were 0.0110 (95% CI, 0.0039 to 0.0182) in men and 0.0112 (95% CI, −0.0040 to 0.0265) in women. Conclusion: In this large prospective study, relative muscle power was a stronger predictor of mortality than relative strength in middle-aged and older men and women. Evaluating and training muscle power could be of clinical and practical relevance.