Background: This work sought to identify characteristics differing between those with and without muscle cramping during a 161-km ultramarathon.
Methods: In this observational study, race participants underwent body weight measurements before, during, and after the race; completed a post-race questionnaire about muscle cramping and “near” cramping (controllable, not reaching full-blown cramping), drinking strategies, and use of sodium supplementation during four race segments; and underwent a post-race blood draw for determination of serum sodium and blood creatine kinase (CK) concentrations.
Results: The post-race questionnaire was completed by 280 (74.5 %) of the 376 starters. A post-race blood sample was provided by 181 (61.1 %) of the 296 finishers, and 157 (53.0 %) of finishers completed the post-race survey and also provided a post-race blood sample. Among those who completed the survey, the prevalence of cramping and near cramping was 14.3 and 26.8 %, respectively, with greatest involvement being in the calf (54 %), quadriceps (44 %), and hamstring (33 %) muscles. Those with cramping or near cramping were more likely to have a prior history of muscle cramping during an ultramarathon (p < 0.0001) and had higher blood CK concentrations (p = 0.001) than those without cramping. Weight change during the race, use of sodium supplements, intake rate of sodium in supplements, and post-race serum sodium concentration did not differ between those with and without cramping.
Conclusions: Muscle cramping is most common in those with a prior history of cramping and greater muscle damage during an ultramarathon, suggesting an association with relative muscular demand. Impaired fluid and sodium balance did not appear to be an etiology of muscle cramping during an ultramarathon.
This is the publisher's version of the work. This publication appears in Gettysburg College's institutional repository by permission of the copyright owner for personal use, not for redistribution.
Hoffman, Martin D., and Kristin J. Stuempfle. "Muscle Cramping During a 161-km Ultramarathon: Comparison of Characteristics of Those With and Without Cramping." Sports Medicine - Open 1.1 (December 2015), article 24.
Required Publisher's Statement
Original version is available from the publisher at: http://link.springer.com/article/10.1186/s40798-015-0019-7/fulltext.html