Resistance Training Effects on Functional Fitness, Muscular Strength and Explosive Power in Postmenopausal Women are Intensity-Dependent

Introduction. This study investigated the differential effects of low-intensity (LRT) versus high-intensity resistance training (HRT) on muscle strength, power, and functional fitness in community-dwelling older women, an area where the specific influence of training intensity remains unclear despite the known benefits of RT in this population.

Material and Methods. Thirty-six postmenopausal women were randomly allocated, by simple randomization, to three equal groups: LRT, HRT, and sedentary control (SC). Participants in the RT groups trained three times per week for eight weeks at either 40% (LRT) or 80% (HRT) of their one-repetition maximum (1RM). Muscle strength was evaluated using 1RM test. Lower- and upper-limb explosive power was measured via countermovement jump (CMJ) and medicine ball throw (MBT), respectively. Functional fitness was further examined using the 30-second arm curl test (30s-ACT), 30-second chair stand test (30s-CST), back scratch (BS), chair sit-and-reach (CSR), stepping down test (SDT), and stepping up test (SUT).

Results. In the LRT and HRT groups, functional fitness (including the 30s-ACT, 30s-CST, BS, CSR, SDT, and SUT) and muscle strength (1RM) were significantly improved at 8 weeks compared with the SC group. Only the HRT group exhibited significant enhancements in explosive power (both CMJ and MBT). Compared with the LRT, the HRT showed additional significant improvements in overall functional fitness, whole-body strength and explosive power.

Conclusions. The benefits of RT on functional ability, strength, and explosive power among postmenopausal women are strongly dependent on training intensity.