Is symmetry of loading improved for injured runners during novice barefoot running?

BACKGROUND: As barefoot (BF) running provides important sensory information that influence landing patterns, it may also affect loading symmetry.

RESEARCH QUESTION: The purpose of this investigation was to examine whether symmetry of loading in a group of injured runners would be improved in a novice, barefoot condition.

METHODS: Cross-sectional design evaluating 67 injured RFS runners. Each subject ran on an instrumented treadmill, first with their habitual shod pattern and then in a BF condition with a FFS pattern, both at the same self-selected speed. Data were averaged over 10 footstrikes. Variables of interest included vertical average load rate, vertical instantaneous load rate, and resultant instantaneous load rate. Symmetry indices (SI) for full population and within quartiles were compared for each loadrate variable (P ≤ 0.05) to evaluate changes between conditions.

RESULTS: On average, symmetry of loading was similar in a novice BF condition of injured runners compared with their habitual RFS shod condition. However, a subanalysis of quartiles revealed that the injured runners with the highest asymmetry (greatest SI values) displayed significantly lower asymmetry when running BF for all three loadrate measures.

SIGNIFICANCE: The addition of sensory input during barefoot running only improves symmetry of loading when habitual loading is highly asymmetric.