Comparison of ankle kinematics and ground reaction forces between prospectively injured and uninjured collegiate cross country runners.
Kuhman DJ, Paquette MR, Peel SA, Melcher DA.
Hum Mov Sci. 2016 Jan 28;47:9-15. doi: 10.1016/j.humov.2016.01.013.
Biomechanical comparative studies on running-related injuries have included either currently or retrospectively injured runners. The purpose of this study was to prospectively compare ankle joint and ground reaction force variables between collegiate runners who developed injuries during the cross country season and those who did not. Running gait analyses using a motion capture system and force platform were conducted on 19 collegiate runners prior to the start of their cross country season. Ten runners sustained running-related injuries and 9 remained healthy during the course of the season. Strike index, peak loading rate of the vertical ground reaction force, dorsiflexion range of motion (ROM), eversion ROM, peak eversion angle, peak eversion velocity, and eversion duration from the start of the season were compared between injury groups. Ankle eversion ROM and peak eversion velocity were greater in uninjured runners while peak eversion angle was greater in injured runners. Greater ankle eversion ROM and eversion velocity with lower peak eversion angle may be beneficial in reducing injury risk in collegiate runners. The current data may only be applicable to collegiate cross country runners with similar training and racing schedules and threshold magnitudes of ankle kinematic variables to predict injury risk are still unknown.
Influence of Step Rate on Shin Injury and Anterior Knee Pain in High School Runners.
Luedke LE, Heiderscheit BC, Williams DS, Rauh MJ.
Med Sci Sports Exerc. 2016 Jan 26.
PURPOSE: High school cross country runners have a high incidence of injury, particularly at the shin and knee. An increased step rate during running has been shown to reduce impact forces and loading of the lower extremity joints. The purpose of this prospective study was to examine step rate as a risk factor for
MATERIALS/METHODS: Running step rates of 68 healthy high school cross country runners (47 females; 21 males; mean age 16.2±1.3 yrs) were assessed at a fixed speed (3.3±0.0 m/s) and self-selected speed (mean 3.8±0.5 m/s). Runners were prospectively followed during the interscholastic season to determine athletic exposures, occurrences of shin injury and anterior knee pain, and days lost to injury.
RESULTS: During the season, 19.1% of runners experienced a shin injury and 4.4% experienced anterior knee pain. Most injuries (63.6%) were classified as minor (1-7 days lost). At the fixed speed, runners in the lowest tertile of step rate (≤164 steps/min) were more likely (OR=6.67; 95% CI, 1.2-36.7; p=0.03) to experience a shin injury compared to runners in the highest tertile (≥174 steps/min). Similarly, for self-selected speed, runners in the lowest tertile (≤166 steps/min) (OR=5.85; 95% CI, 1.1-32.1; p<0.04) were more likely to experience a shin injury than runners in the highest tertile (≥178 steps/min). Anterior knee pain incidence was not significantly influenced by step rate. CONCLUSION: A lower running step rate was associated with a greater likelihood of shin injury at both self-selected and fixed running speeds. Future studies evaluating whether increasing running step rate reduces shin injury risk and time lost during a high-school cross country season should be considered.