Yes, supplemental magnesium may improve exercise performance but only in individuals that are magnesium deficient [ 1 2 1 2 
2]. Magnesium is involved in energy metabolism, cardiorespiratory function, and muscle actions, and when we don’t get enough of it, sports performance suffers accordingly [
2]. Additionally, athletes who engage in more intense exercises may require 10-20% more magnesium than the general population due to higher urinary and sweat losses
. Magnesium has not been shown to prevent or relieve exercise-related muscle cramps .
 Zhang, Y., Xun, P., Wang, R., Mao, L., & He, K. (2017). Can Magnesium Enhance Exercise Performance? Nutrients, 9(9), 946. https://doi.org/10.3390/nu9090946
 Nielsen, F. H., & Lukaski, H. C. (2006). Update on the relationship between magnesium and exercise. Magnesium research, 19(3), 180–189. https://pubmed.ncbi.nlm.nih.gov/17172008/
 Garrison, S. R., Korownyk, C. S., Kolber, M. R., Allan, G. M., Musini, V. M., Sekhon, R. K., & Dugré, N. (2020). Magnesium for skeletal muscle cramps. The Cochrane database of systematic reviews, 9(9), CD009402. https://doi.org/10.1002/14651858.CD009402.pub3