VISUAL GUIDANCE TO FORCE PLATES DOES NOT INFLUENCE GROUND REACTION FORCE VARIABILITY

Gait analysis methods commonly require the subject to avoid visual gui dance, that is, targeting, the force plate upon which a foot-strike is necessary. The putative rationale underlying the preference for not u sing targeting is the unsubstantiated contention that gait is altered. This study evaluated the influence of force plate targeting on the va riability of ground reaction forces (GRF) in 15 normal subjects. Secon dary factors of single vs multiple steps to the force plate and whethe r or not subjects were informed of the study's primary purpose were al so examined. ANOVA main effects revealed that targeting did not signif icantly affect GRF variability (p > 0.05). A significant main effect o f the number of steps required to reach the force plate on AP force va riability was found (P = 0.002). Prior knowledge of the purpose of the study did not significantly affect GRF variability (p > 0.05). It was concluded that the variability of ground reaction forces is not signi ficantly affected by targeting the force plate. Thus, targeting would not be expected to influence the variability of calculated kinetic var iables that are subservient to GRF.