Nonlinear analysis reveals duration and gradient-dependent disruption of load carriage gait variability during an outdoor 6.72 km time trial in military personnel
研究通过分析14名军事人员负重行军时的步态数据，发现持续时间显著影响步态变异性，而坡度影响虽大但不显著，提示长时间行军可能增加受伤风险。
This investigation assessed the effect of gradient and duration on the gait variability exponent, DFA-α, in military personnel affixed with dual inertial measurement units performing a load carriage time-trial. Gait data (N = 14) were partitioned into 256 stride time segments by gradient (uphill, downhill) using a gait event algorithm. Detrended fluctuation analysis calculated DFA-α per segment, which was averaged across one-third durations (phases 1–3) per gradient. Two-way repeated measures ANOVA examined effects of gradient, duration, and interaction on DFA-α, with Bonferroni-adjusted post-hoc comparisons. There was a significant main effect of duration (phase 1: 0.593 ± 0.021; phase 2: 0.563 ± 0.031; phase 3: 0.493 ± 0.021; F = 3.833, p = 0.035, η p 2 = 0.228), but not gradient (uphill: 0.486 ± 0.031; downhill: 0.614 ± 0.035; F = 4.252, p = 0.060, η p 2 = 0.246), or interaction (F = 0.019, p = 0.981, η p 2 = 0.001). Pairwise comparisons revealed significantly lower DFA-α during phase 3 than phase 1 (p = 0.016). Elapsed duration and uphill gradient, despite a large, but non-significant effect, may represent factors altering gait variability for injury risk.