Phase-specific force–time adaptations in basketball jump shots under environmental constraints

This study examined whether task-related and environmental constraints influence the vertical ground reaction force (vGRF) waveform during the basketball jump shot, with a focus on phase-specific adaptations across shooting positions. Eighteen senior basketball players performed jump shots from three shooting positions (45° right, middle, 45° left) under three conditions: baseline, simulated defensive opposition, and simulated gym audience noise. vGRF signals were recorded using a force platform and time-normalized to 0–100% of the movement cycle. One-dimensional Statistical Parametric Mapping (SPM) was applied using a hierarchical region-of-interest (ROI) approach, focusing on the unweighting, braking, and propulsive phases. Group-level effects were tested using a two-way SPM{F} ANOVA (Constraint × Position). Exploratory intra-individual SPM{t} analyses were conducted to examine athlete-specific adaptations. No significant main effects of constraint or position, and no constraint × position interactions were observed at the group level in any ROI (α = 0.05). Exploratory intra-individual analyses revealed heterogeneous, athlete-specific adaptations to external constraints and shooting position, predominantly during the braking and propulsive phases, with substantial variability in the timing and presence of significant clusters across athletes. The results indicate that experienced basketball players preserve a stable force–time organization during the jump shot despite environmental and task-related constraints. While group-level mechanical patterns remain invariant, individual athletes may exhibit phase-specific adaptations that do not generalize across the population. These findings underscore the importance of hierarchical and individualized analytical approaches for understanding skilled performance and support the use of ROI-based SPM for the biomechanical analysis of complex movement tasks.