The effects of pressure on anticipatory postural adjustments during a jump shot in basketball

Background

Anticipatory postural adjustments (APAs) play an important role in feedforward control of dynamic movements, such as jump shot performance in basketball. It is known that jump shot performance declines under pressure from a defender (shot blocker).

Research question

Does pressure from a shot blocker affect the APAs of a jump shot in basketball? Is jump shot performance in basketball associated with APAs?

Methods

Fourteen healthy male university basketball players performed jump shots under pressure and non-pressure (free) conditions by a shot blocker. Using a force plate, the APAs were defined as occurring until the point of thrust (TH) phase, and ground reaction force (GRF) and center of pressure (COP) at that moment were assessed. To assess jump shot performance, the maximum GRF during the TH phase (TH_max), jumping height, and success score of the shot (accuracy score: AS) were measured by using the vertical component of the force plate. Two-way ANOVA examined the effects of the phase and condition on APA duration. The effects of pressure from a shot blocker on each variable (subjective pressure intensity, AS, GRF, and COP) were analyzed using a pairwise t-test or Wilcoxon signed-rank tests. Relationships between changes in jump shot performance and GRF or COP variables were assessed via Spearman’s correlation analysis. Differences between the pressure and free conditions were denoted by p/f (pressure/free).

Results

The APA duration was shorter under the pressure condition compared to the free condition. The TH_max and jump height values were greater under the pressure condition relative to the free condition. Across conditions, changes in COP sway velocity of the APA phase were significantly and negatively correlated with AS.

Significance

The results of this study suggest that pressure from a shot blocker shortens APA duration and decreases jump shot performance.