Effects of marathon running on running economy and kinematics

• Published in: European journal of applied physiology 2000-07, Vol.82 (4), p.297-304
• Main Authors: Kyröläinen, H, Pullinen, T, Candau, R, Avela, J, Huttunen, P, Komi, P V
• Format: Article
• Language: English
• Subjects: Adult; Biomechanical Phenomena; Body temperature; Consumption; Creatine Kinase - blood; Energy; Energy Metabolism; Female; Fitness equipment; Heart Rate; Humans; Kinematics; Lactic Acid - blood; Male; Marathons; Mechanics; Metabolism; Muscle, Skeletal - physiology; Norepinephrine - blood; Oxygen Consumption; Physiology; Plasma Volume; Running; Running - physiology; Triathlon; Troponin I - blood
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s004210000219

The present study was designed to investigate interactions between running economy and mechanics before, during, and after an individually run marathon. Seven experienced triathletes performed a 5-min submaximal running test on a treadmill at an individual constant marathon speed. Heart rate was monitored and the expired respiratory gas was analyzed. Blood samples were drawn to analyze serum creatine kinase activity (S-CK), skeletal troponin I (sTnI), and blood lactate (B-La). A video analysis was performed (200 frames x s(-1)) to investigate running mechanics. A kinematic arm was used to determine the external work of each subject. The results of the present study demonstrate that after the marathon, a standardized 5-min submaximal running test resulted in an increase in oxygen consumption, ventilation, and heart rate (P < 0.05), with a simultaneous decrease in the oxygen difference (%) between inspired and expired air, and respiratory exchange ratio (P < 0.05). B-La did not change during the marathon, while sTnI and S-CK values increased (P < 0.05), peaking 2 h and 2 days after the marathon, respectively. With regard to the running kinematics, a minor increase in stride frequency and a similar decrease in stride length were observed (P < 0.01). These results demonstrate clearly that weakened running economy cannot be explained by changes in running mechanics. Therefore, it is suggested that the increased physiological loading is due to several mechanisms: increased utilization of fat as an energy substrate, increased demands of body temperature regulation, and possible muscle damage.