Feasibility of Lower-Body EMS Resistance Training in Postmenopausal Women

This pilot randomized controlled trial evaluates whether combining lower-body electrical muscle stimulation (EMS) with resistance training is feasible and beneficial for physically inactive postmenopausal women, who experience concurrent declines in muscle strength, body composition, arterial elasticity, and cardiac autonomic balance. Sixteen physically inactive postmenopausal women aged 50-70 years are randomly assigned (1:1) to either (A) supervised resistance training combined with lower-body EMS (applied to 6 muscle groups: lower back, lower abdomen, glutes, quadriceps, hamstrings, and calves) or (B) supervised resistance training alone. Both groups complete twelve 50-minute sessions (consisting of a 10-minute warm-up, 30-minute main exercise, and a 10-minute cool-down) over 6 weeks (twice weekly). Assessments before and after the intervention include body composition, lower-body muscle function, arterial stiffness, and 5-minute heart rate variability. The primary aim is to determine the feasibility of the protocol(recruitment, retention, session attendance, and intervention dose delivery) to inform a future definitive trial. Preliminary estimates of intervention effects on the measured outcomes are reported as secondary aims.

Inclusion Criteria: * Women aged 50 to 70 years. * Menopause for at least 1 year with no current menstruation. * Physically inactive (have not participated in resistance training more than twice a week for the past 6 months) Exclusion Criteria: * Currently receiving hormone replacement therapy (HRT). * Presence of implanted electrical medical devices. * Severe or uncontrolled medical conditions. * Any surgery within the past 6 months. * Acute illness with fever, infection, or active inflammation. * Severe peripheral arterial disease or abdominal/inguinal hernia. * Severe psychiatric disorders requiring medication, or current substance abuse. * Deemed physically or mentally unfit to participate in the exercise program by the investigator.