Speed and accuracy tradeoff in whole body movement during vertical jumps under varying landing constraints.

The speed-accuracy trade-off, described by Fitts' law, has been well studied in fine motor tasks but remains insufficiently explored in whole-body movements, such as jumping. This gap limits our ability to identify universal motor control principles applicable to fine and gross motor tasks. To address this, we investigated the influence of landing accuracy constraints on vertical jump performance. Twelve participants performed jumps under four conditions: no accuracy constraints and progressively smaller target areas (100%, 65%, and 36% of the force-plate surface). Stricter accuracy demands a reduced jump height and systematic adjustments in the magnitude and direction of the take-off velocity. Notably, these trade-offs occurred despite the participants' inability to continuously monitor the target during the jump, relying instead on the initial recognition of accuracy constraints. Entropy analysis revealed decreased variability in landing positions, reflecting precise motor adaptations to meet the task requirements. These findings suggest that principles similar to Fitts' law govern speed-accuracy trade-offs in whole-body movements. This study provides valuable insights for sports, rehabilitation, and robotics applications by illustrating how accuracy constraints shape dynamic full-body movements.