Lifelong fitness training plays an essential role in building and maintaining health. Whole-body electromyostimulation (WB-EMS) is a time-efficient training method that could be used as an adequate training intervention for different persons due to the intensive, involuntary contraction of the musculature and the resulting increases in muscular performance. Therefore, the aim of the study was to investigate if WB-EMS has positive effects on body composition and physical performance parameters of individuals of different age decades. Subjects from age decades 20-80 years participated in a 24-week WB-EMS training intervention. PRE and POST diagnostics of trunk extension and flexion, knee extension and flexion, hand grip strength, skeletal muscle mass (SMM) and body fat were performed on three consecutive days and the daily maximum values were summarized as the total mean value and were used for the descriptive data interpretation. Strength parameters were summarized in an unweighted additive index, the muscular change index (MCI). Regarding the results obtained by using the MCI, remarkable increases were observed in participants from all decades (20: +12.02%; 30: +6.59%; 40: +6.85%; 50: +3.96%; 60: +10.95%; 70: +20.26%; 80: +20.86%). Therefore, WB-EMS seems to be a time-efficient and adequate form of training that can be conducted to enhance muscular performance at different ages.