Accurate estimation of skeletal muscle mass across the lifespan using simple field tests of strength and power
摘要
This study aimed to develop regression equations to estimate (1) absolute whole-body skeletal muscle mass (SMM), (2) SMM normalized for height squared (SMM/height2), and (3) SMM normalized for body mass index (SMM/BMI) using simple anthropometric and performance variables.
Methods541 participants (6–87 years, both sexes) were assessed for SMM using bioelectrical impedance analysis, handgrip strength, normalized rate of force development (nRFD), and countermovement jump (CMJ) height. Hierarchical multiple regression analyses were used to develop predictive equations, and their accuracy was tested in a cross-validation group using linear regression and Bland–Altman analyses.
ResultsThe developed equations demonstrated high accuracy for estimating SMM and SMM/height2 (adjusted R2 = 0.875–0.964; SEE = 6.4%–7.2%), whereas the accuracy for SMM/BMI was lower (adjusted R2 = 0.671–0.740; SEE = 14.1%–15.9%) when tested in the cross-validation group. Including CMJ height alongside handgrip strength improved the prediction accuracy, and nRFD contributed significantly to SMM/BMI estimation. Exploratory analyses showed that the association between SMM and performance indices was affected by age and sex, whereas nRFD was not influenced by these factors.
ConclusionThe SMM can be accurately estimated using simple field-based measures of body size and muscle function. Combining handgrip strength and CMJ height enabled a feasible and size-independent assessment of muscle mass with a wide range of ages in both sexes. Even when only handgrip strength and CMJ height were included as performance variables, the developed equations achieved high predictive accuracy, highlighting their practical applicability in the field and clinical settings.