Anaerobic Speed Reserve, Sprint Force-Velocity Profile, Kinematic Characteristics, and Jump Ability among Elite Male Speed- and Endurance-Adapted Milers.

This study aimed to compare sprint, jump performance, and sprint mechanical variables between endurance-adapted milers (EAM, specialized in 1500-3000-m) and speed-adapted milers (SAM, specialized in 800-1500 m) and to examine the relationships between maximal sprint speed (MSS), anaerobic speed reserve (ASR), sprint, jump performance, and sprint mechanical characteristics of elite middle-distance runners. Fifteen participants (8 EAM; 7 SAM) were evaluated to obtain their maximal aerobic speed, sprint mechanical characteristics (force-velocity profile and kinematic variables), jump, and sprint performance. SAM displayed greater MSS, ASR, horizontal jump, sprint performance, and mechanical ability than EAM ( p < 0.05). SAM also showed higher stiffness in the 40-m sprint ( p = 0.026) and a higher ratio of horizontal-to-resultant force (RF) at 10 m ( p = 0.003) and RFpeak ( p = 0.024). MSS and ASR correlated with horizontal ( r = 0.76) and vertical ( r = 0.64) jumps, all sprint split times ( r ≤ -0.85), stiffness ( r = 0.86), and mechanical characteristics ( r ≥ 0.56) during the 100-m sprint, and physical qualities during acceleration ( r ≥ 0.66) and sprint mechanical effectiveness from the force-velocity profile ( r ≥ 0.69). Season-best times in the 800 m were significantly correlated with MSS ( r = -0.86). Sprint ability has a crucial relevance in middle-distance runners' performance, especially for SAM.