We have recently assessed a 33-year-old female patient, an aerobic athlete who practises 180min of swimming and 30km (18.6miles) of trotting per week, and who complained about proximal weakness and pain in lower limbs associated with noticeable volume increase in both thighs, of one day of evolution. Patient did not have any medical history of interest and was not taking any medication. The day before, she had used, for the first time, an electrostimulation device on the painful area while performing her regular exercises, which involved running on a treadmill for 30min. The device consisted of short pants with electrodes for muscle stimulation of both glutei. The program used by the patient had a frequency of 50Hz in accordance with the manufacturer's data sheet. The patient presented pain on palpation in quadriceps and lateral heads of triceps brachii and she showed proximal weakness that conditioned her pace. From the analytical point of view, she showed normal renal function, creatine phosphokinase (CPK) of 64,150U/l, lactate dehydrogenase (LDH) 616mg/dl, glutamate pyruvate transaminase (GPT) 640UI/l, glutamate-oxalacetate transaminase (GOT) 1050UI/l and myoglobinuria ++/+++. She was treated with overhydration and bed rest for 3 days, after which the pain ceased significantly; the thighs volume was reduced, the myoglobinuria disappeared and the CPK descended to 1222U/l. Two months later, all analytes were normalised and the patient went back to her regular sport activity without presenting new symptoms until after 6 months from the episode. Approximately 3 months after the episode, she had an electromyography done which did not identify a pattern compatible with neuropathy or myopathy. A lactate test was performed with normal results.

Post-exercise rhabdomyolysis is a process that can present itself in healthy subjects or in patients with metabolic muscular diseases. It is characterised by a lysis of the musculoskeletal striated fibre after physical exertion that manifests itself clinically as the triad of myalgia, weakness and choluria.1–3 Its management is mainly support-oriented, and it consists of athletic rest and overhydrating to prevent renal failure secondary to myoglobinemia.4,5 In scientific literature, there is only one case of rhabdomyolysis associated with the use of an electrostimulation device in a young male patient who was exposed to such device for several weeks.6 Electrostimulation devices allow the performance of passive physical exercise through electrodes that generate isometric contractions in specific muscle areas.7 These devices are available for domestic use and at gymnasiums since their popularity lies on the promise of physical conditioning without the need of performing voluntary physical exertion. Our patient was exposed to electrostimulation once, which is a fact that stands out when comparing her case with the one described in 2004 by Guarascio et al.6 However, our patient performed her regular aerobic routine while carrying the electrostimulation device in both thighs. The complete analytical normalisation, the electromyographic study, the normality in the lactate test and the reincorporation to regular physical activity reasonably rule out that the patient suffers from any muscular metabolic disease. The main risk factors associated with the development of rhabdomyolysis are lack of physical conditioning and the performance of extreme muscular exertion.8 Our patient was a young woman who was used to physical activity. However, in our opinion, the use of a muscle electrostimulator while performing physical activity may generate tensile strengths capable of provoking the disruption of the muscle fibre's integrity with the well-known consequences. Due to lack of more cases, we cannot establish a universal recommendation advising against the use of electrostimulators. Nevertheless, common sense suggests that their use should not be made while performing active exercises.