Article

Locomotor variability is inherent to movement and, in healthy systems, contains a
predictable structure. In this study, detrended fluctuation analysis (DFA) was
used to quantify the structure of variability in locomotion. Using DFA,
long-range correlations (alpha) are calculated in over ground running and the
influence of injury and fatigue on alpha is examined. An accelerometer was
mounted to the tibia of 18 runners (9 with a history of injury) to quantify
stride time. Participants ran at their preferred 5k pace+/-5% on an indoor track
to fatigue. The complete time series data were divided into three consecutive
intervals (beginning, middle, and end). Mean, standard deviation (SD),
coefficient of variation (CV) and alpha of stride times were calculated for each
interval. Averages for all variables were calculated per group for statistical
analysis. No significant interval, group or intervalxgroup effects were found for
mean, SD or CV of stride time. A significant linear trend in alpha for interval
occurred with a reduction in alpha over the course of the run (p=0.01) indicating
that over the run, stride times of runners became more unpredictable. This was
likely due to movement errors associated with fatigue necessitating frequent
corrections. The injured group exhibited lower alpha (M=0.79, CI(95)=0.70, 0.88)
than the non-injured group (p=0.01) (M=0.96, CI(95)=0.88, 1.05); a reduction
hypothesized to be associated with altered complexity. Overall, these findings
suggest injury and fatigue influence neuromuscular output during running.
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Langue : ANGLAIS