Key result
Mountain ultramarathon linked to increased slow myosin and creatine kinase, indicating slow-fiber disruptions.
Why the study?
Changes in serum concentrations of fiber-type-specific sarcomere proteins after a mountain ultramarathon and their relation to muscle damage biomarkers were not well characterized.
Does a mountain ultramarathon increase serum concentrations of fast and slow myosin isoforms, CK, and cTnI in endurance-trained amateur athletes?
Observational (n=8)
Does a mountain ultramarathon increase serum concentrations of fast and slow myosin isoforms, CK, and cTnI in endurance-trained amateur athletes?
p-value: p=.009
Prolonged mountain running increases slow myosin serum concentrations, suggesting slow-fiber-specific sarcomere disruptions without significant cardiac troponin I elevation.
May indicate selective slow-fiber muscle disruption after ultramarathons without cardiac involvement; leaves open myosin isoforms as injury biomarkers in athletes.
OBJECTIVE: To investigate changes after a mountain ultramarathon (MUM) in the serum concentration of fast (FM) and slow (SM) myosin isoforms, which are fiber-type-specific sarcomere proteins. The changes were compared against creatine kinase (CK), a widely used fiber-sarcolemma-damage biomarker, and cardiac troponin I (cTnI), a widely used cardiac biomarker. METHODS: Observational comparison of response in a single group of 8 endurance-trained amateur athletes. Time-related changes in serum levels of CK, cTnI, SM, and FM from competitors were analyzed before, 1 h after the MUM, and 24 and 48 h after the start of the MUM by 1-way ANOVA for repeated measures or Friedman and Wilcoxon tests. Pearson correlation coefficient was employed to examine associations between variables. RESULTS: While SM was significantly (P = .009) increased in serum 24 h after the beginning of the MUM, FM and cTnI did not change significantly. Serum CK activity peak was observed 1 h after the MUM (P = .002). Moreover, serum peaks of CK and SM were highly correlated (r = .884, P = .004). CONCLUSIONS: Since there is evidence of muscle damage after prolonged mountain running, the increase in SM serum concentration after a MUM could be indirect evidence of slow- (type I) fiber-specific sarcomere disruptions.
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Carmona et al. (2015) conducted an observational in Muscle damage (n=8). Mountain ultramarathon vs. Baseline (before the ultramarathon) was evaluated on Changes in serum concentration of fast and slow myosin isoforms, creatine kinase, and cardiac troponin I (p=.009). A mountain ultramarathon significantly increased serum concentrations of slow myosin isoforms at 24 hours (P=0.009) and creatine kinase at 1 hour (P=0.002), indicating slow-fiber disruptions.
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