Mechanical stiffness: a global parameter associated to elite sprinters performance

Abstract This study analyzes vertical stiffness as a global parameter that could be directly associated to sprinter's performance. We evaluated vertical stiffness, performance, heart rate and lactate concentration on fifteen male sprinters that ran on a treadmill at gait transition speed and 13 km h−1. Vertical Stiffness was determined by the ratio of the vertical acceleration peak and maximum displacement of the center of mass. Physiological parameters were measured throughout the experimental procedure and performance was estimated by athlete's time records on 100 m track race. As expected, vertical stiffness and heart rate increased with running speed. We found a high correlation between heart rate and vertical stiffness at gait transition speed. However, at 13 km h−1, lactate peak showed a higher correlation with vertical stiffness, suggesting a greater participation of the anaerobic system. An inverse relationship between performance and vertical stiffness was found, where faster athletes were the stiffer ones. Performance and lactate peak presented the same inverse relationship; faster athletes had higher lactate peaks. As a result, faster athletes were stiffer and consume more energy. All in all, these findings suggest that mechanical stiffness could be a potential global parameter to evaluate performance in sprinters