Relationships between Energy Cost and Kinematic Responses of Trained Runners to Variable-Gradient Running

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Nutrition Exercise and Health Sciences

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The purpose of this study was to elucidate how changes in running gradients (level, incline, decline) influence the relationship between the energy cost of running and running kinematics. Thirteen trained male runners (VO2 peak, 62 ± 5 mL∙kg-1∙min-1) completed three different treadmill trials: (a) 20-min fixed-speed (14.4 km∙h-1) level-gradient trial; (b) 20-min fixed-speed (14.4 km∙h-1) variable-gradient trial; and (c) 3 km self-selected-speed variable-gradient trial. Oxygen consumption (VO2), heart rate (HR), stride length (SL), and stride rate (SR) were measured. When running at a fixed speed, SL decreased (P<0.001) during incline compared to level gradients. Further, a faster incline SR was associated with a greater increase in VO2 during incline gradient running (P=0.02). During the 3 km variable-gradient trial, self-selected running speed was slower during incline (P<0.001). The slower incline speed corresponded with a shorter SL during incline relative to level and decline gradients (P<0.001). However, a longer incline SL was associated with better overall performance (P<0.05). These data demonstrate that incline running, either at a fixed or self-selected treadmill speed, appears to influence stride kinematics more so than decline running. Moreover, the observed kinematic adjustments to an incline were associated with a relatively greater increase in VO2 during incline running. These findings have important implications for training and the performance of runners that compete over undulating terrain.


This article was originally published in Journal of Exercise Physiology. The full-text article from the publisher can be found here.

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Journal of Exercise Physiology