Menopause is associated with losses in strength and power along with weight and fat mass gains, which may result from menopause-related hormonal changes, aging-associated diseases, and decreased physical activity time. The objective of this study is to analyze if whole-body electromyostimulation (WB-EMS) is suitable for the prevention and treatment of postmenopausal physical deterioration. Thirty-four healthy sedentary women between 55 and 69 years followed an experimental design pre-post test. Both groups conducted 10 weeks of aerobic and strength training program. The experimental group conducted the training with superimposed WB-EMS during exercise. At the end of the intervention, the experimental group obtained better power (Squat: mean difference (MD) = 38.69 W [1.75,75.62], d = 0.81; Bench press: MD = 25.64 W [17.48, 33.82], d = 2.39) and velocity (Squat: MD = 0.04 m·s −1 [0.01, 0.08], d = 0.98; Bench press: MD = 0.10 m·s −1 [0.06, 0.14], d = 1.90) score improvements than the other group (pBonferroni < 0.05). Furthermore, trivial to small effects were found in the body composition of the participants of both groups (p > 0.050). WB-EMS showed a favorable isolated effect on the development of power and velocity, but it induced negligible effects on the body composition of postmenopausal women.