Author(s): SKUTSCHIK, C., BEHRINGER, M., Institution: GOETHE UNIVERSITY FRANKFURT, Country: GERMANY, Abstract-ID: 2144

INTRODUCTION:
Muscle cramps, characterized by sudden, involuntary muscle contractions often accompanied by intense pain, affect a vast majority of the population including athletes. While most individuals experience these painful episodes irregularly, certain groups, particularly those affected by nocturnal cramps, endure significant impairment to their quality of life, not least due to sleep disturbances. In previous studies, the efficacy of neuromuscular electrical stimulation (NMES) under controlled laboratory conditions has been demonstrated to reduce the frequency of muscle cramps and susceptibility to cramping [1,2]. Aim of this case study was to test the feasibility of a NMES cramp training conducted at home.
METHODS:
A 56-year-old female (BMI: 25.5) underwent a 4-week NMES cramp training of 8 sessions (2 per week) in a home-based setting.
All other measurements were conducted in the laboratory both before and after the training intervention.
The training comprised 3 sets, each consisting of 6 stimulation trains lasting 5s, 10 s pause. The frequency was set to 30 Hz above the cramp threshold frequency (CTF). The CTF of the m. gastroc. med. was measured by NMES using trains of rectangular biphasic pulses of 200 ms width, amplitude: 40 mA, increasing the frequency from 4 – 40 Hz until cramp occurrence. Cramp onset was detected via electromyography (EMG).
Frequency, intensity, and locations of spontaneous muscle cramps were recorded by the participant in a cramp diary before and during the intervention. A questionnaire evaluating quality of life (SF12), sleep quality (PSQI), muscle cramp characteristics, and cramp score was administered during two distinct laboratory visits, with a 4-week intervention period separating them.
RESULTS:
Prior to the intervention the participant reported daily (mostly nocturnal) muscle cramps with a mean frequency of 4.2 cramps/day, range: 3-5.
During the 4-week intervention period the cramp frequency was reduced by ~74%: mean: 1.1 cramps/day, range 0-5.
The CTF increased from 14 Hz (Pre) to 22 Hz (Post). Cramp intensity decreased by ~6,4% and sleep quality increased tremendously: PSQI score: 14 (Pre) to 5 (Post).
The participant didn´t report any negative outcomes or problems regarding the intervention period.
CONCLUSION:
The results of this case study show that the positive effect of previous laboratory studies on NMES cramp training can also be achieved in a self-administered home setting. Both the cramp threshold and the frequency of spontaneous muscle cramps were reduced, leading to a better quality of life and better sleep.
This approach promises a practical and efficient alternative, allowing participants to undergo training at home with minimal time impact, while also optimizing resource allocation for researchers.
REFERENCES:
1) Behringer et al. Neuromodulation, 2018
2) Harmsen et al. Neuromodulation, 2021