Total Body and Extracellular Water Measures Are Unrelated to Cramp Sensitivity in Euhydrated Cramp-Prone Individuals.

Earp, JE, Stearns, RL, Agostinucci, J, Lepley, AS, and Ward-Ritacco, CL. Total body and extracellular water measures are unrelated to cramp sensitivity in euhydrated cramp-prone individuals. J Strength Cond Res 36(9): 2653-2656, 2022-Spectral bioelectrical impedance analysis (BIA) is a valid and noninvasive tool for measuring total body water (TBW), intracellular water (ICW), and extracellular water (ECW). As altered hydration and electrolyte imbalance have been proposed as one of 2 etiologies for exercise-associated muscle cramps (EAMC), the purpose of this study was to determine if distribution of body water is related to cramp sensitivity in similarly hydrated cramp-prone individuals. To this end, 11 euhydrated subjects who regularly experience EAMC had their relative TBW, ICW, and ECW assessed using 8-pole spectral BIA. Subjects' cramp sensitivity was then assessed by electrically stimulating the tibial nerve at increasing frequencies until a muscle cramp occurred, allowing for the determination of the threshold frequency (TF) at which the cramp occurred. It was observed that TF was not significantly related to TBW ( r = 0.087, p = 0.368), ICW ( r = 0.105, p = 0.338), ECW ( r = 0.087, p = 0.368), or ECW:TBW ( r = 0.147, p = 0.280). As cramp etiology is poorly understood, these results add to a growing body of literature questioning the role of hydration and electrolyte imbalance in EAMC. Although fluid distribution may be unrelated to TF in those who commonly experience EAMC, additional research is needed to compare those who commonly experience cramps (athletes as well as individuals with specific neuropathies or pharmacologically induced cramps) with those who do not experience cramps and to determine if acute shifts in body water compartmentalization are related to changes in cramp sensitivity.