The Biomechanical Signature of Elite Distance Running: A Matched Pairs Analysis Across Multiple Speeds.

This study compared the biomechanical profiles of elite and recreational distance runners across five measurement domains using wearable inertial sensors across treadmill speeds of 10-15 km/h. A total of 104 runners (52 elite; 52 recreational) were assessed using RunScribe sensors during an incremental treadmill protocol. Twenty-three variables spanning spatiotemporal parameters, stiffness and force, impact loading, foot kinematics and vertical dynamics were recorded at each speed. Elite runners were matched 1:1 with recreational runners by sex, age, height, and body mass. For each variable, a linear mixed-effects model (LMM) was fitted to within-pair differences with pair-level random intercepts and speed slopes, and speed and within-pair body mass and age imbalances as fixed effects. FDR correction (Benjamini-Hochberg) was applied to the 23 group-effect and 23 interaction tests independently. Twelve of 23 variables (52.2%) showed a significant group effect, and six (26.1%) a significant group×speed interaction after FDR correction. Elite runners showed shorter contact time (dz = -0.73 to -0.53), higher flight ratio (dz = +0.52 to +0.66) and a more anterior footstrike pattern at initial contact (dz = +0.58 to +0.67). RunScribe-estimated vertical GRF rate and leg stiffness were also higher than in recreational runners (dz = +0.48 to +0.75, and + 0.51 to +0.62, respectively). Step frequency and step length showed no overall group difference. Significant group×speed interactions revealed that, for most affected variables, values changed more steeply with speed in recreational runners. These findings describe a distinct mechanical profile in elite runners across the six evaluated submaximal speeds.