Behringer Michael, Moser Markus, McCourt Molly, Montag Johannes, Mester Joachim
Institute of Training Science and Sport Informatics, German Sport University Cologne, Cologne, Germany.
PLoS One. 2014 Apr 11;9(4):e94910. doi: 10.1371/journal.pone.0094910. eCollection 2014.
To investigate if the cramp threshold frequency (CTF) can be altered by electrical muscle stimulation in a shortened position.
A total of 15 healthy male sport students were randomly allocated to an intervention (IG, n = 10) and a non-treatment control group (CG, n = 5). Calf muscles of both legs in the IG were stimulated equally twice a week over 6 weeks. The protocol was 3×5 s on, 10 s off, 150 µs impulse width, 30 Hz above the individual CTF, and was at 85% of the maximal tolerated stimulation energy. One leg was stimulated in a shortened position, inducing muscle cramps (CT), while the opposite leg was fixated in a neutral position at the ankle, hindering muscle cramps (nCT). CTF tests were performed prior to the first and 96 h after the 6(th) (3 w) and 12(th) (6 w) training session.
After 3 w, the CTF had significantly (p<0.001) increased in CT calves from 23.3±5.7 Hz to 33.3±6.9 Hz, while it remained unchanged in nCT (pre: 23.6±5.7 Hz, mid: 22.3±3.5 Hz) and in both legs of the CG (pre: 21.8±3.2 Hz, mid: 22.0±2.7 Hz). Only CT saw further insignificant increases in the CTF. The applied stimulation energy (mA² • µs) positively correlated with the effect on the CTF (r = 0.92; p<0.001).
The present study may be useful for developing new non-pharmacological strategies to reduce cramp susceptibility.
German Clinical Trials Register DRKS00005312.
探讨在肌肉缩短状态下，电肌肉刺激是否能改变抽筋阈值频率（CTF）。
15名健康男性体育专业学生被随机分为干预组（IG，n = 10）和非治疗对照组（CG，n = 5）。IG组的双腿小腿肌肉每周接受两次同等强度刺激，持续6周。刺激方案为：每次刺激3×5秒，间隔10秒，脉冲宽度150微秒，频率比个体CTF高30赫兹，刺激能量为最大耐受刺激能量的85%。一条腿在肌肉缩短状态下接受刺激，诱发肌肉痉挛（CT），而另一条腿在踝关节处固定于中立位，防止肌肉痉挛（nCT）。在第1次训练前以及第6次（3周）和第12次（6周）训练后的96小时进行CTF测试。
3周后，CT小腿的CTF显著升高（p<0.001），从23.3±5.7赫兹升至33.3±6.9赫兹，而nCT小腿（训练前：23.6±5.7赫兹，训练中：22.3±3.5赫兹）以及CG组双腿（训练前：21.8±3.2赫兹，训练中：22.0±2.7赫兹）的CTF保持不变。只有CT小腿的CTF有进一步不显著的升高。施加的刺激能量（毫安²•微秒）与CTF变化效果呈正相关（r = 0.92；p<0.001）。
本研究可能有助于开发新的非药物策略以降低抽筋易感性。
德国临床试验注册中心DRKS00005312 。
