Feasibility of Lower-Body EMS Resistance Training in Postmenopausal Women

BACKGROUND AND RATIONALE Postmenopausal women often experience physiological declines in muscle function, body composition, and cardiovascular health. While resistance training is an established countermeasure, maximizing its efficiency and adherence remains a challenge. Applying lower-body electrical muscle stimulation (EMS) during resistance training may enhance physiological adaptations and overall training effectiveness. This study aims to evaluate the feasibility of combining lower-body EMS with resistance training in physically inactive postmenopausal women to inform the design of a future definitive trial. STUDY DESIGN This is a pilot randomized controlled trial. Participants will be randomly assigned to either an intervention group receiving combined lower-body EMS and resistance training or a control group receiving resistance training alone. Clinical and physiological outcomes will be assessed before and after the intervention period to evaluate preliminary effects. PRIMARY FEASIBILITY OUTCOMES The primary objective is to evaluate the feasibility of the study protocol. Feasibility will be determined by assessing several key components, including: Recruitment: The ability to recruit the target population within the planned timeframe. Retention: The proportion of participants who complete the study and post-intervention assessments. Adherence: Participant attendance and compliance with the scheduled exercise sessions. Intervention Fidelity: The successful delivery of the exercise intensity and EMS protocol as intended. These components will be evaluated against pre-established progression criteria to determine whether the protocol can proceed to a larger trial or requires modification. STATISTICAL APPROACH Feasibility outcomes will be summarized primarily using descriptive statistics. For secondary physiological and clinical outcomes, appropriate statistical methods will be utilized to estimate the preliminary effects of the intervention, comparing changes between the groups while adjusting for baseline measurements. Effect sizes and confidence intervals will be calculated to provide preliminary evidence and to assist with sample size calculations for future large-scale trials.