Edinburgh Napier University

  Perception-Action coupling (PAC) is the reciprocal animal/environment interaction by which actions are controlled. Successful PAC requires accurate perception of affordances (opportunities for action), in relation to action capabilities/boundaries. Accuracy is dependent on the congruence of the perceptual awareness of action boundaries (distance of a gap to be jumped) in relation to changes in action capabilities (additional load). Military personnel carry up to 60% of body weight (BW) when performing operational tasks. The addition of such loads have been shown to effect landing mechanics and ground reaction forces, thus increasing the opportunity for injury. Safe execution of a jump across a gap when carrying an additional load requires accurate PAC with respect to the changes in action capabilities.

PURPOSE: Examine the effects of additional load on PAC with respect to horizontal jumping distance.

METHODS: Maximum jump distances of 17 participants (Age=24.8+3.6yrs; Ht=179.3+6.7cm; Wt=80.2+14.7kg) were established in 3 load conditions (BW, BW+15%, and BW+30%); representing their action boundaries. Participants were presented with the opportunity to jump 4 different distances (90, 95, 100, and 105% of their max jump distance). Six trials of each distance in each load condition were performed in a randomized order; split over 2 days. Participants were instructed that if they perceived the distance to be ‘jumpable’ then jump, if not turn around. Percentage correct responses were analysed using the Friedman test to determine any significant differences in action response for load and distance conditions.

RESULTS: Accuracy of PAC decreased significantly (p