Evidence · 7 min · 1 September 2026

Cramp is usually not what you think it is

The salt explanation is the popular one. The evidence for it is weaker than almost anybody realises.

Almost every player who comes to me about cramp has already tried adding salt, and about half have tried a magnesium supplement. Most of them are still cramping.

What the evidence actually supports

The strongest current explanation is neuromuscular — altered control at the level of the muscle spindle and Golgi tendon organ, usually when a muscle is fatigued and working in a shortened position. That is why cramp so often arrives late in a match and in the same muscle each time.

Where dehydration and sodium fit

They are associated with cramp in some studies and not others, and the trials that deliberately dehydrate people often fail to produce it. That does not mean hydration is irrelevant — it means it is unlikely to be the whole answer, and treating it as the whole answer is why the salt did not work.

What I would look at first

Your training load in the two weeks before it started, whether the cramp is always the same muscle, and whether you are getting enough total energy. In practice, load and under-fuelling explain more of the cases I see than sodium does.

What this is not

This is general information, not advice about you. Cramp that is new, severe or happening at rest is a reason to see a doctor rather than a dietitian.

General information, not advice about an individual. Every figure on this site is illustrative. What I can and cannot tell you →