Table 1.

Clinical Severity of EAMCs^a

Cramp-prone state or precramping9,48
Heightened neuromuscular excitability (near-cramping state) is identified by involuntary muscle fasciculations or twitching. Resting EMG activity is higher than in noncramping muscles. The cramp-prone state is usually self-limiting and self-treatable if activity stops or decreases.
Mild or moderate (benign)9
The EAMC is localized to a muscle or muscle group. Resting EMG activity is higher than in noncramping muscles. The EAMCs occur without other systemic symptoms or signs of a concomitant, more serious injury (eg, hyponatremia). These EAMCs are usually self-limiting and treatable if activity stops or decreases.
Severe or serious or EAMCs as a sign of a systemic condition2
Localized or generalized EAMCs may occur with more serious systemic symptoms or signs, including dizziness, collapse, nausea or vomiting, dark urine, or altered state of consciousness (eg, confusion, coma). These symptoms or signs indicate the presence of a more serious underlying or concomitant medical condition (eg, serum electrolyte abnormality, kidney injury). Resting EMG activity is higher in both cramping and noncramping muscles, indicating general neuromuscular excitability. These EAMCs necessitate immediate exercise cessation, correct diagnosis and medical intervention for the underlying medical condition, and likely transport to a hospital.

Abbreviations: EAMC, exercise-associated muscle cramp; EMG, electromyography.

^aThe EAMCs can progress in severity from mild to severe (as a continuum) during exercise.