Hey Phil.
Short answer: not really much to be done here except for improve fitness, which is a more long-term play as you know.
Long answer: Exercise Associated Muscle Cramps are painful, involuntary contractions of skeletal muscle that occurs during or immediately after exercise.
With respect to severity, they are on a continuum ranging from “pre cramping or cramp prone” with twitching/fasciculations, to moderate with a single muscle or muscle group cramp that’s self-limiting, to severe, which tends to be associated with other signs/symptoms like nausea, vomiting, dark urine, altered mental status, and more.
The severity does seem to correlate with increased resting EMG activity of the affected muscles, but the cause is complicated.
Enter the classic explanation regarding dehydration and electrolyte imbalance. This theory proposes that as a person loses body water (e.g. becomes hypohydrated), there are more and more excitatory neurochemicals and mechanical pressure are present on nerve terminals, which cause the muscle to fire and contract.
There are a few problems with this theory though:
- When studied, plasma osmolarity, body mass change due to water loss, and electrolyte concentrations are the same in those with and without exercise associated muscle cramps.
- If this theory were try, and because body water and electrolyte losses are systemic, cramps should occur in any muscle, not just the working ones.
- When studied, those with cramps consume similar amounts of fluid during exercise as those without cramps.
- Stretching relieves cramping but does not alter fluid or electrolyte levels
- When studied, there were no cramps with up to 5% body weight loss from sweating without associated exercise-related fatigue.
Overall, cramps are probably multifactorial related to fatigue and other factors.
As far as treatment and prevention goes, we recommend treating with self-administered stretching. No specific type is better than the other. We also recommend improving training status and fitness levels.For example, marathoners who experienced cramps were less likely to perform once-per-week lower extremity strength training in the 3 months leading up to a race than their non-cramping counterparts, suggesting that strength training may be helpful in preventing cramps.
Mitigating fatigue is also important. Fatigue is hypothesized to be a main factor in cramp development and overexertion is often tied to cramps, so it is vital to ensure that athletes exercise with appropriate balancing of practice, training, and competition loads.
Lastly, a number of things don’t work based on available evidence:
- Rehydration is not terribly useful due to time course to effect (>10 min, at fastest) and likely to be hypotonic anyway (diluting electrolytes further)
- Cooling. Cramps aren’t really to passive heating nor relieved by cooling modalities
- Bananas. Potassium is generally not considered an electrolyte of interest in cramps, yet bananas are sometimes used during treatment due to their high potassium and glucose content. Some data suggested they are unlikely to help by increasing blood potassium, as dehydrated participants who ingested 1 or 2 servings of bananas postexercise did not experience increases in plasma potassium concentrations or plasma volume until 60 minutes after consumption. Interestingly, plasma glucose increased significantly in the 2-servings trial, but this effect occurred 15 minutes post ingestion. There’s no real evidence exists on their efficacy.
- Magnesium. A 2020 Cochrane review reported that magnesium supplementation offered no clinically meaningful benefits in terms of cramp frequency, intensity, or duration compared with placebo.
- Salt supplementation. When studied in isolation, adding salt to diet does not seem to affect incidence of cramps. There are studies showing that a 6% carbohydrate-electrolyte beverage with added salt delayed cramp onset by ~ 20 minutes compared to when nothing was consumed, but this doesn’t really support salt supplementation, as the experimental design prohibited identification of the ingredient responsible for this effect because the drink contained multiple ingredients. Also, the athletes still experienced cramping so….probably not terribly useful.
- Stretching. Although static stretching effectively treats cramps, it appears to be ineffective as a prophylactic strategy. One study did 3 1-minute bouts of PNF stretching prior to exercise did not reduce cramp susceptibility. In a series of observational studies, researchers consistently failed to demonstrate relationships among flexibility, range of motion, and stretching frequency, duration, or timing and cramp occurrence.