Relationship Between Running Biomechanics And Core Temperature Across A Competitive Road Race

Outdoor races introduce environmental stress to runners, and thermal responses may influence runners’ movement patterns. Lightweight technologies offer a means to quantify biomechanical and core temperature measures throughout competition. PURPOSE: The purpose of this study was to assess changes and determine relationships between sensor-derived running biomechanics and core temperature among runners across an 11.27-km (7-mi) road race. METHODS: Twenty runners (9 F, 11 M; age: 48 ± 12 y; height: 169.7 ± 9.1 cm; mass: 71.3 ± 13.4 kg) enrolled in the 2022 Falmouth Road Race (11.27 km; 7 mi) were recruited for participation. Participants were provided ingestible thermistors to monitor core temperature, and lace-mounted wearable sensors to assess biomechanics (spatiotemporal, kinematic, and kinetic outcomes) during the race. Time stamps were used to align sensor measures for seven race segments. Observations were labeled as elevated core temperatures (≥38 °C) or within normal limits (<38 °C). Multivariate repeated measures analyses of variance were used to assess changes in sensor-derived measures across the race, with Bonferroni post-hoc tests for significant findings. Pearson’s correlations were used to assess the relationship between sensor-derived measures across the race among those who had elevated core temperatures. RESULTS: 18 participants developed elevated core temperatures (39.0 ± 0.5 °C); core temperatures significantly increased across the race (7th to the 1st segment: 1.6 ± 0.1°; p < 0.001). There was a significant main effect for kinetic outcomes across the race (p = 0.003); post-hoc assessments reflected that shock, impact, and braking all significantly increased across the race (0.8-1.1 g; p-range < 0.001-0.005). Remaining biomechanics outcomes did not significantly change (p-range: 0.36-0.83). Among those with elevated core temperatures, thermal responses were significantly correlated with longer stride lengths (r = 0.21, p = 0.04), longer contact times (r = 0.22, p = 0.03), and higher impacts (r = 0.21, p = 0.04). CONCLUSIONS: Increased core temperatures were associated with increased contact time and impact forces over a race, both of which have been linked to lower running economy. Our findings highlight a potential association between biomechanics and thermal response in runners. ORS Sport