Marathon runners who cramped showed more muscle damage, not less salt
Twenty of 88 marathon finishers cramped. They matched everyone else on sodium, potassium and hydration, and carried more of the enzymes that leak from injured muscle.
What the study found
Marathon crampers carried more damaged muscle, not less sodium
If not salt, then what. Twenty of 88 marathon finishers cramped, matching everyone else on sodium, potassium and hydration while carrying more of the enzymes that leak from injured muscle: creatine kinase 464 against 383 units per litre at the finish, and more than double a day later.
The caveat · The cramp may have caused the damage
Twenty crampers is a small group, and the finish-line enzyme gap is borderline at p = 0.034 with spreads wide enough to swallow it. The blood was drawn after the cramp, so muscle damage could as easily follow a cramp as cause one. Crampers and non-crampers only diverged in pace from 25 kilometres onward, which points back at effort. The paper's own abstract calls 20 of 88 a rate of 24 percent; it is 22.7 percent.