Muscle cramps, muscle spasms and charlie horses. We have all had those quick, non voluntary contraction of a muscle that is unable to relax. It can be painful, and at times, hard to manage. Whether while going for a run or laying in bed at night, muscle cramps, or spasms, are not comfortable. Muscle cramps can occur in both sedentary people as well as very active people and the causes can vary. In fact, throughout their careers triathletes experience a prevalence of muscle cramping of 67% and marathon runners 30-50% (1).
There are a few kinds of muscle cramps, or muscle spasms. There are exercise-associated muscle cramping and nocturnal cramps. This article will address more of the exercise induced muscle cramps.
What is an exercise-associated muscle cramp or EAMC? It is defined as syndrome of involuntary painful skeletal muscle spasms that happens during or immediately after a workout (2). These cramps usually occur in localized, specific muscles and the research shows that muscles that cross more than one joint, such as the hamstring or gastroc, are more likely to experience EAMC (1).
What causes muscle spasms?
A few risk factors that may lead to exercise-associated muscle cramps include long distance or high-intensity running, shorter daily stretching time or irregular stretching habits, competing at a pace faster than training and hot weather. There are also other factors including older age, higher BMI and underlying chronic diseases including the cardiovascular, respiratory, gastrointestinal, nervous system, kidney, bladder and hematological diseases (3).
The causes of exercise induced muscle cramping is thought to occur due to two theories: local muscle fatigue caused by altered neuromuscular control and electrolyte deficits (1). It is likely, though, that these two causes often can occur together.
The electrolyte imbalance therapy is the older of the two theories and is thought to occur due to dehydration, heat accumulation, electrolyte loss, and metabolic accumulation (3). Excessive sweating can cause a loss of sodium and/or chloride as well as reduced plasma volume (1). This essentially can make it easier for the muscle to inappropriately engage thus causing cramps.
The second theory regarding local muscle fatigue caused by altered neuromuscular control is supported by a more robust body of literature (4). This theory proposes that exercise associated muscle cramping is due to a neuromuscular imbalance between the excitatory and inhibitory properties of the body (5). Essentially, the muscle tries to contract when it is already contracting, thus causing a cramping sensation. This may typically happen at the end of competition or a more intense training session when the muscle is already in an engaged state.
What is the best way to stop muscle spasms?
How do we go about addressing this? Commonly known, the most immediate intervention that can be performed for an exercise-associated muscle cramp is a slow, static, and gentle stretch of the involved muscle. Another popular remedy is to ingest pickle juice due to its high sodium content. A study actually showed that ingesting small volumes of pickle juice (80 ml) relieved muscle cramps 37% faster than water or nothing at all during an exercise induced muscle cramp (6).
How are exercise associated muscle cramps prevented?
While they are most likely due to muscle fatigue, appropriate condition and rehabilitation from an injury is important. Proper rehab following an injury will ensure the athlete is not overstressing their body or returning to pre-injury level of function at an inefficient rate. A case study has also shown that incorporating gluteal strengthening exercises into a triathletes routine resolved persistent hamstring cramping during competition (1). A regular stretching routine as well as a good dynamic warm up that prepares the muscles for activity may be an effective way to reduce the risk, though this is not a proven strategy.
If you have any questions regarding muscle cramping that may be exercise induced contact The Fit Institute for an injury screening today!
Thomas Dyke, PT, DPT, OCS
Orthopedic Clinical Specialist
- Wagner T, Behnia N, Ancheta WK, Shen R, Farrokhi S, Powers CM. Strengthening and neuromuscular reeducation of the gluteus maximus in a triathlete with exercise-associated cramping of the hamstrings. journal of orthopaedic & sports physical therapy. 2010 Feb;40(2):112-9.
- Miller KC. Exercise-associated muscle cramps. InExertional Heat Illness 2020 (pp. 117-136). Springer, Cham.
- Bergeron MF. Muscle cramps during exercise-is it fatigue or electrolyte deficit?. Current Sports Medicine Reports. 2008 Jul 1;7(4):S50-5.
- Nelson NL, Churilla JR. A narrative review of exercise‐associated muscle cramps: Factors that contribute to neuromuscular fatigue and management implications. Muscle & nerve. 2016 Aug;54(2):177-85.
- Marosek SE, Antharam V, Dowlatshahi K. Quantitative Analysis of the Acetic Acid Content in Substances Used by Athletes for the Possible Prevention and Alleviation of Exercise-Associated Muscle Cramps. The Journal of Strength & Conditioning Research. 2020 Jun 1;34(6):1539-46.