Compromised Dynamic Postural Stability Under Increased Load Carriage Magnitudes

in Journal of Applied Biomechanics
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Warfighter performance may be compromised through the impact of load carriage on dynamic postural stability. Men and women may experience this impact to differing extents due to postural stability differences. Therefore, the authors investigated the effect of load magnitude on dynamic postural stability in men and women during a landing and stabilization task. Dynamic postural stability of 32 subjects (16 women) was assessed during the unilateral landing of submaximal jumps under 3 load conditions: +0%, +20%, and +30% body weight. Dynamic postural stability was measured using the dynamic postural stability index, which is calculated from ground reaction force data sampled at 1200 Hz. Two-way mixed-measures analysis of variance compared dynamic postural stability index scores between sexes and loads. Dynamic postural stability index scores were significantly affected by load (P = .001) but not by sex or by the sex by load interaction (P > .05). Dynamic postural stability index scores increased between the 0% (0.359 ± 0.041), 20% (0.396 ± 0.034), and 30% (0.420 ± 0.028) body weight conditions. Increased load negatively affects dynamic postural stability with similar performance decrements displayed by men and women. Men and women warfighters may experience similar performance decrements under load carriage conditions of similar relative magnitudes.

LaGoy, Johnson, Allison, Flanagan, Lovalekar, and Connaboy are with the Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA. Nagai is with the Orthopedic Biomechanics Laboratory, Mayo Clinic, Rochester, MN, USA. LaGoy is also with the Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA.

LaGoy (adl59@pitt.edu) is corresponding author.
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