G-22 Thematic Poster - Does Symmetry Matter? Saturday, June 4, 2016, 9:00 AM - 11:00 AM Room: 101
PURPOSE: Running injuries are often attributed to biomechanical asymmetries. The improved sensory input of barefoot running may result in reduced asymmetries. The purpose of this study was to compare the symmetry of loading between typical shod and barefoot running conditions.
METHODS: 99 habitual rearfoot strike, shod runners (53 females, average age ± SD: 38 ± 13) presenting at a running injury clinic were included in this study. Subjects first ran on an instrumented treadmill at a self-selected speed (average: 5.7±0.5 miles per hour). They then ran at the same speed barefoot with instructions and visual cues to maintain a forefoot strike pattern. Symmetry Index (SI) was calculated for vertical force peak (VP), average load rate (ALR), instantaneous load rate (ILR), and stance time (ST). Higher SI values denote less symmetry between left and right values. The data were analyzed for the entire data set and by quintile.
RESULTS: When assessing all subjects, SI for ALR (10.07±8.41, 15.62±11.15) and ILR (9.76±8.60, 15.89±11.78) were higher in barefoot conditions (P<0.01), whereas SI for VP (2.90±2.02, 3.10 ±2.05) and ST (2.29±1.92, 2.58±2.19) were not different between shod and barefoot conditions, respectively. When assessing those with the greatest degree of asymmetry (the highest quintile SI values) symmetry improved for nearly all of the variables when going from shod to barefoot condition (see table 1).
CONCLUSION: These results suggest that symmetry is generally improved during typical barefoot running compared to shod. Improved sensory input may contribute to this improvement in symmetry. If so, barefoot running may be used as a way to train to achieve more symmetrical gait patterns, especially in those with the greatest asymmetries.