Biomechanical changes identified during a marathon race among high-school aged runners.

BACKGROUND: Despite the increasing popularity of endurance running competitions among adolescent runners, there is currently limited information regarding expected biomechanical changes across the duration of a long-distance running event, and the relationship between young runners' biomechanics and running performance. Wearable technology offers an ecological means to continuously assess runners' biomechanical data during outdoor running competitions.

RESEARCH QUESTION: Do adolescent athletes adopt changes in sensor-derived biomechanics throughout a marathon race, and are there relationships between race performance and biomechanical features among young marathoners?

METHODS: Fourteen high-school aged runners (9 M, 5 F; age: 16 ± 1 years, height: 170.8 ± 7.5 cm; mass: 63.6 ± 9.4 kg) wore lace-mounted sensors to record step-by-step biomechanics during a marathon race. Official race segment completion times were extracted across 5 race segments (5-K, 15-K, Half Marathon [21.1-K], 35-K, Marathon [42.2-K]). Within-participant repeated measures of covariance (pace) were conducted to assess changes in biomechanics across the race, with Bonferroni post-hoc comparisons. Pearson's r correlations were performed to assess the relationship between race finish times and biomechanics.

RESULTS: Pace was significantly slower (p-range: 0.002-0.005), contact times significantly longer, and stride lengths significantly shorter in the final segment compared to middle segments (p-range: 0.003-0.004). The rate of shock accumulation was significantly higher in the final race segment compared to the first three segments (p-range: 0.001-0.002). Moderate relationships existed between finish times and pace (r = -0.63), stride length (r = -0.62), and contact time (r = 0.51).

SIGNIFICANCE: Adolescent runners altered their gait patterns in the final marathon segment compared to earlier segments. Spatiotemporal measures were moderately correlated with race finish times, suggesting a link between faster run pace, increased stride lengths, and reduced contact time for improved running performance during an endurance race.