Running Pace Decrease during a Marathon Is Positively Related to Blood Markers of Muscle Damage
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Date
2013-02-27Author
Del Coso, Juan
Fernández, David
Abián Vicen, Javier
Salinero, Juan José
González Millán, Cristina
Areces, Francisco
Ruiz, Diana
Gallo, César
Pérez González, Benito
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PLoS ONE 8(2) : (2013) // e57602
Abstract
Background: Completing a marathon is one of the most challenging sports activities, yet the source of running fatigue during this event is not completely understood. The aim of this investigation was to determine the cause(s) of running fatigue during a marathon in warm weather.
Methodology/Principal Findings: We recruited 40 amateur runners (34 men and 6 women) for the study. Before the race, body core temperature, body mass, leg muscle power output during a countermovement jump, and blood samples were obtained. During the marathon (27 uC; 27% relative humidity) running fatigue was measured as the pace reduction from the first 5-km to the end of the race. Within 3 min after the marathon, the same pre-exercise variables were obtained.
Results: Marathoners reduced their running pace from 3.5 6 0.4 m/s after 5-km to 2.9 6 0.6 m/s at the end of the race (P,0.05), although the running fatigue experienced by the marathoners was uneven. Marathoners with greater running fatigue (. 15% pace reduction) had elevated post-race myoglobin (1318 6 1411 v 623 6 391 mg L21; P,0.05), lactate dehydrogenase (687 6 151 v 583 6 117 U L21; P,0.05), and creatine kinase (564 6 469 v 363 6 158 U L21; P = 0.07) in
comparison with marathoners that preserved their running pace reasonably well throughout the race. However, they did
not differ in their body mass change (23.1 6 1.0 v 23.0 6 1.0%; P = 0.60) or post-race body temperature (38.7 6 0.7 v 38.9 6 0.9 uC; P = 0.35).
Conclusions/Significance: Running pace decline during a marathon was positively related with muscle breakdown blood
markers. To elucidate if muscle damage during a marathon is related to mechanistic or metabolic factors requires further
investigation.