Abstract
BACKGROUND: Little is known about changes in kinetics or kinematics following a 10 km training run. This information has implications on risk of running-related injury. PURPOSE: The purpose of this study was to examine the effect of a 10 km run on running kinematics and kinetics in a sample of experienced runners. STUDY DESIGN: Cross-Sectional Study. SUBJECTS: Nineteen runners ages 18-48 (7 female, 12 male) consented to participate including eight (3 female, 5 male) ultra-runners, and 11 (4 female, 7 male) recreational runners. METHODS: Following collection of demographic data and completion of a short running survey, participants did a 6-minute run at their self-selected running speed to acclimate to the instrumented treadmill. Reflective markers were placed over designated anatomical landmarks on both sides of the pelvis as well as the left lower extremity and marked with a skin pen. Subjects then ran on the treadmill and 30 seconds of video data were recorded at 240 frames/sec using a high-speed camera for the sagittal plane and the frontal plane. Simultaneously, ground reaction forces (GRFs) were recorded at 1200 Hz through the treadmill's embedded force plates. Each runner then ran 10 km on a paved trail at their self-selected pace. Immediately following the run, reflective markers were reattached, guided by markings placed before the run, and a 30-second post-run trial of the video and GRF data were recorded. Video data were analyzed using Kinovea software to measure the kinematic variables of interest. Paired t-tests with Bonferroni corrections were used to find if significant differences existed between pre- and post-run data for all kinematic and kinetic variables. RESULTS: No significant or clinically relevant differences existed between the pre- and post-run measurements for the kinematic or kinetic variables. The only significant difference noted between the ultra-runners and recreational runners was that the ultra-runners had significantly higher cadence (p=0.045). CONCLUSIONS: A 10 km run at a self-selected pace did not result in change in the mean kinematic or kinetic variables in this group of experienced runners. Ultra-runners employ higher cadence than recreational runners, but their kinematics and kinetics are similar. LEVEL OF EVIDENCE: Level 3.