Effects of an Eight-Week Combined Isometric and Elastic-Resistance Training Program on Body Composition and Functional Fitness in Older Women

Abstract

This exploratory randomized trial evaluated an eight-week combined isometric and elastic-resistance program in community-dwelling women aged 70 years or older. Forty-nine participants were randomized to exercise (EG; n = 24) or control (CG; n = 25). Twenty-two EG participants completed the intervention and follow-up; two had no post-intervention measurements because of scheduling conflicts. All randomized participants were included in the intention-to-treat analysis using 50 data sets generated by predictive mean matching and baseline-adjusted analysis of covariance. Compared with the CG, the EG showed lower body weight (adjusted mean difference [AMD], −0.45 kg), BMI (−0.19 kg/m2), 4 m gait time (−0.96 s), and five-repetition chair-stand time (−1.60 s), and higher skeletal muscle mass (0.38 kg), calf circumference (0.80 cm), and handgrip strength (1.01 kg). The corresponding primary 95% confidence intervals excluded zero, although the skeletal-muscle-mass interval narrowly included zero under conservative imputation. Differences in body fat percentage (−0.33 percentage points; 95% CI, −1.24 to 0.58) and tandem-stance time (0.79 s; 95% CI, −0.42 to 2.00) were inconclusive. These preliminary findings suggest that the program may improve selected body-composition and functional outcomes. Larger prospectively powered trials are required to confirm their magnitude, clinical relevance, and durability.