Due to its individualization, time-efficiency and effectiveness Whole-body-Electromyo-stimulation (WB-EMS) becomes increasingly popular. However, recently (very) high Creatin-kinase concentration were reported, at least after initial WB-EMS-application. Thus, the aim of the study was to determine (1) WB-EMS induced increases of CK-concentration, (2) their impact on corresponding health parameters and (3) training-induced changes of CK-levels.Twenty-six healthy, sportive volunteers without previous experience with WB-EMS were included. Initial high intense WB-EMS application (bipolar, 85 Hz; 350 ms; intermittent, 20 min) led to an increase of the CK-level by the 117fold (28.545 ± 33.611 IU/l) of baseline. CK-peaks were detected after 72-96 h. Despite this pronounced "exertional rhabdomyolysis", we did not determine rhabdomyolysis-induced complications (e.g. acute renal failure, hyperkalemia, hypocalcaemia). After 10 weeks of WB-EMS (1 session/week) CK-reaction to intensive WB-EMS-Application was significantly blunted (906 ± 500 IE/l) and averaged in the area of conventional resistance exercise.In summary, intensity of WB-EMS should be carefully increased during the initial sessions.