Tony Lin-Wei Chen1, Duo Wai-Chi Wong2, Yan Wang2, Qitao Tan3, Wing-Kai Lam4, Ming Zhang5. 1. Department of Biomedical Engineering, Faculty of Engineering, Hong Kong Polytechnic University, Hong Kong SAR 999077, China; Li Ning Sports Science Research Center, Li Ning (China) Sports Goods Co. Ltd, Beijing 101111, China. 2. Department of Biomedical Engineering, Faculty of Engineering, Hong Kong Polytechnic University, Hong Kong SAR 999077, China; Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China. 3. Department of Biomedical Engineering, Faculty of Engineering, Hong Kong Polytechnic University, Hong Kong SAR 999077, China. 4. Li Ning Sports Science Research Center, Li Ning (China) Sports Goods Co. Ltd, Beijing 101111, China; Department of Kinesiology, Shenyang Sports Institute, Shenyang 110102, China. Electronic address: gilbertlam@li-ning.com.cn. 5. Department of Biomedical Engineering, Faculty of Engineering, Hong Kong Polytechnic University, Hong Kong SAR 999077, China; Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China. Electronic address: ming.zhang@polyu.edu.hk.
Abstract
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.
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.
Authors: Tommy J Cunningham; David R Mullineaux; Brian Noehren; Robert Shapiro; Timothy L Uhl Journal: Clin Biomech (Bristol, Avon) Date: 2013-12-17 Impact factor: 2.063