Are electrically induced muscle cramps able to increase the cramp threshold frequency, when induced once a week?

Abstract

The cramp threshold frequency (CTF) is known to be positively correlated with the individual cramp susceptibility. Here we assessed CTF changes after two bouts of electrically induced muscle cramps (EIMCs). The EIMCs (6×5 sec) were unilaterally induced twice (separated by one week) in the gastrocnemius of an intervention group (n=8), while 5 participants served as control. The CTF increased from 25.1±4.6 Hz at baseline to 31.4±9.0 Hz and 31.7±8.5 Hz 24 h after bout 1 and 2 (P<0.05). Thereafter, the CTF declined following both bouts to reach values of 28.0±6.7 Hz and 29.1±7.7 Hz after 72 h after bout 1 and 2. Creatine kinase (CK) activity and perceived discomfort during cramps was lower after bout 2 (P<0.05). CTF, CK, and discomfort did not change in CG. That is, a single bout of EIMCs induces a 24 h CTF increment and a second bout sustains this effect, while perceived discomfort and muscle damage decreases. This short term effect may help athletes to reduce the cramp susceptibility for an important match.

Cramp Training Induces a Long-Lasting Increase of the Cramp Threshold Frequency in Healthy Subjects

“…However, the durability of those effects remain unclear as the longest follow‐up period after such an intervention ended 96 hours after the last cramp training session. In a more recent study we found that a single bout of EIMCs only resulted in a short‐term increase of the CTF with a peak at 24 hours after the intervention . A second bout that was applied 1 week later was not able to further increase the CTF values but induced a very similar response pattern, when compared to the first bout.…”

“…Using a handheld battery‐powered myostimulator (Cefar Compex, Compex 3 Professional, Compex Médical SA, Ecublens VD), the gastrocnemii of the participants were stimulated in a seated position with their legs hanging down freely. As described previously the stimulation protocol of the applied cramp training consisted of three sets of six stimulation trains that lasted for 5 sec each, interrupted by 10 sec breaks. The stimulation amplitude was set to 85% of the maximally tolerated stimulation current (mTSC), which was tested prior to every cramp training.…”

“…The impulse width was set to 400 µsec and the stimulation frequency was set to 30 Hz above the individual CTF (see below). These protocol was selected as it has previously shown to induce marked increases of the CTF .…”

Muscle cramp susceptibility increases following a volitionally induced muscle cramp

“…How muscle cramps affect future cramp propensity is unknown, and our study does not provide clarity in this regard. However, muscle cramps are painful injuries that affect maximum force production and may even elicit some degree of muscle damage (as indicated by increases in creatine kinase and muscle soreness) . Evidence from well‐designed experimental and cohort studies suggests pain may play a role in cramp genesis.…”

A narrative review of exercise-associated muscle cramps: Factors that contribute to neuromuscular fatigue and management implications

“…The CTF of the calf muscles receiving stimulation in a shortened position was increased significantly at 3 ( P < 0.001) and 6 ( P < 0.001) weeks, whereas no significant changes were noted at either assessment point in the contralateral legs of the intervention participants or in the calf muscles of participants in the control group. In a follow‐up study, Behringer et al . found that 2 bouts of electrically induced muscle cramps (EIMC), induced 1‐week apart in the gastrocnemius of an intervention group ( n = 8), raised the CTF significantly for 24 hours in each of the 2 bouts ( P < 0.05).…”