Vertical or horizontal force–velocityprofile

This study aimed to determine which task (jumping or sprinting) and which force-velocity (F-V) relationship parameter (maximal force [ F 0], maximal velocity [ v 0], or maximal power [Pmax]) is the most sensitive indicator of fatigue induced by a basketball-specific protocol. Following a familiarization session, 19 junior male basketball players completed an experimental session in which both vertical (jumping) and horizontal (sprinting) F-V profiles were measured before, during and after undergoing a basketball-specific fatigue protocol (modified version of the Loughborough Intermittent Shuttle Test). All F-V relationship parameters, except horizontal F0 (p = .328), were significantly reduced after fatigue (p ≤ .042). The vertical Pmax (ES = -0.48 to -0.80), horizontal Pmax (ES = -0.58 to -1.28), and horizontal v 0 (ES = -0.81 to -0.98) showed larger reductions compared to the pre-fatigue assessment than the vertical v 0 (ES = -0.19 to -0.27), vertical F 0 (ES = -0.16 to -0.25), and horizontal F 0 (ES = -0.11 to -0.30). When the percentage changes with respect to the pre-fatigue assessment were compared between the jumping and sprinting tasks, no significant differences in their magnitude (p ≥ .364) and trivial to small correlations (-0.23 ≤ r ≤ 0.19) were detected. The results suggest that Pmax is the most suitable parameter to detect fatigue following a basketball-specific fatigue protocol, while the lack of significant correlations for the changes in F-V relationship parameters highlight the importance of measuring both the vertical and horizontal F-V profiles to gain comprehensive understanding of the changes in the mechanical properties of lower-body muscles following fatigue protocols.