Context: Feedback has been used to reduce peak vertical ground reaction (VGRF) during landing, yet the use of technology to allow for real-time adjustments during landing has not been evaluated. Objective: Determine effects of real-time feedback (RTF) and traditional feedback (TF) on VGRF and inter-limb VGRF symmetry during landing compared to jumping and control conditions. Design: Single blinded, randomized controlled trial. Participants: Thirty healthy females randomized into 4 groups(RTF:n=7,21.1±1.5yrs,164.0±5.5cm,63.4±7.1kg; TF:n=8,20.8±2.1yrs, 165.4± 5.2cm,61.6±3.4kg;Control:n=8,21.3±1.2yrs,162.6±6.8cm,66.0±18.5kg;Jumping:n=7,22.7±3.5yrs,166.6±6.2cm,68.6±14.22 kg). Interventions: RTF and TF participants completed 18 jump-landings with feedback following each set. RTF group was equipped with markers on the lower extremity. Markers on patella and great-toe were highlighted, and connected with a line. RTF participants aligned their knee-foot segment with vertical reference line during landing. Control participants sat quietly for 10 minutes. Jumping participants performed 18 jumps without feedback. Outcome Measures: Three pre-intervention jumps and three post-intervention jumps were recorded. Peak VGRF was calculated for each limb and normalized to mass. Repeated measures ANOVA and Tukey post hoc comparisons assessed changes in VGRF, and inter-limb symmetry ((dominant VGRF/non-dominant VGRF)*100). Pre-intervention VGRF values were used as a covariate, accounting for baseline group differences in right VGRF analysis. Alpha was set a priori at P<0.05. Results: Post-intervention right RTF VGRF was lower than control (RTF vs. control:1.47±0.29, 2.27±0.36;P=0.001) and jumping (RTF vs. jumping:1.47±0.29, 2.03±0.23,P=0.018). Left RTF(1.24±0.16) VGRF was lower compared to control(1.82±0.24,P=0.006). No significant group by time interaction for inter-limb symmetry on landing observed(P=0.448). Conclusion: Reduction in VGRF observed following RTF without a change in inter-limb symmetry.
Listed In: Biomechanics