标题：Changes in segment coordination variability and the impacts of the lower limb across running mileages in half marathons: Implications for running injuries
摘要：Highlights
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The vertical loading rate was not influenced by running mileages during half marathons.
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Changes in coordination variabilities occurred at the early stance phase of running gaits.
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As the half marathon progressed, coordination variabilities increased in the couplings of pelvis frontal
vs. thigh frontal and shank transverse
vs. rearfoot frontal.
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The increased coordination variabilities on the frontal/transverse planes of motion could be associated with fatigue and indicate injury potential.
Background
Segment coordination variability (CV) is a movement pattern associated with running-related injuries. It can also be adversely affected by a prolonged run. However, research on this topic is currently limited. The purpose of this study was to investigate the effects of a prolonged run on segment CV and vertical loading rates during a treadmill half marathon.
Methods
Fifteen healthy runners ran a half marathon on an instrumental treadmill in a biomechanical laboratory. Synchronized kinematic and kinetic data were collected every 2 km (from 2 km until 20 km), and the data were processed by musculoskeletal modeling. Segment CVs were computed from the angle-angle plots of selected pelvis-thigh, thigh-shank, and shank-rearfoot couplings using a modified vector coding technique. The loading rate of vertical ground reaction force was also calculated. A one-way MANOVA with repeated measures was performed on each of the outcome variables to examine the main effect of running mileage.
Results
Significant effects of running mileage were found on segment CVs (
p ≤ 0.010) but not on loading rate (
p = 0.881). Notably, during the early stance phase, the CV of pelvis frontal
vs. thigh frontal was significantly increased at 20 km compared with the CV at 8 km (
g = 0.59,
p = 0.022). The CV of shank transverse
vs. rearfoot frontal decreased from 2 km to 8 km (
g = 0.30,
p = 0.020) but then significantly increased at both 18 km (
g = 0.05,
p < 0.001) and 20 km (
g = 0.36,
p < 0.001).
Conclusion
At the early stance, runners maintained stable CVs on the sagittal plane, which could explain the unchanged loading rate throughout the half marathon. However, increased CVs on the frontal/transverse plane may be an early sign of fatigue and indicative of possible injury risk. Further studies are necessary for conclusive statements in this regard.
Graphical Abstract
Image, graphical abstract
