Exercise-associated muscle cramps
Painful muscle spasms during or after exercise.
Exercise-associated muscle cramps (EAMC) are painful muscle spasms that occur during or immediately after exercise. They are very common, even among elite athletes, particularly during endurance events such as triathlons or marathons. The cause is not fully understood, as cramping can result from many underlying conditions.
Quick Facts
- Common in
- elite athletes
- Typical events
- endurance events such as triathlon or marathon
Facts from the source article.
Did You Know?
- Medication has not been found to help reduce or prevent muscle cramping.
- Stretching calms spindles by lengthening muscle fibers and increasing firing duration to slow firing rate.
- Recommended fluids during cramping include water or high-electrolyte fluids to replenish sodium.
Electrolyte depletion and dehydration theory
Excessive sweating during strenuous exercise is widely believed to lead to muscle cramps. Deficiency of sodium and other electrolytes may contract interstitial fluid compartments, exacerbating cramping. Increased blood plasma osmolality from sodium loss shifts fluid from interstitial to intravascular space, deforming the interstitial compartment and contributing to muscle hyperexcitability and spontaneous activity.
Neuromuscular control
The second hypothesis proposes that altered neuromuscular control, driven by fatigue, causes cramping. Repetitive muscle exercise leads to fatigue from inadequate conditioning, hot or humid environments, increased intensity or duration, or decreased energy supply. Fatigue increases excitatory afferent activity in muscle spindles and decreases inhibitory afferent activity in Golgi tendon organs. This alters spinal cord neuromuscular control, increasing alpha-motor neuron activity and overloading lower motor neurons, while raising muscle cell membrane activity, resulting in a muscle cramp.
More in Symptoms and Signs: Musculoskeletal System
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