Influence of force reduction within-field variability on peak tibial accelerations using wearable inertial measurement units

Within-field variability of surface characteristics has been found to impact athlete injuries, performance, and perceptions about a surface. Ankle-worn inertial measurement units allow for in-situ research exploring how within-field variability influences athlete biomechanics. This study investigated the effect of force reduction within-field variability on peak tibial accelerations of male collegiate rugby athletes. High and low force reduction areas were delineated within one natural turfgrass and synthetic turf field. Athletes were fitted with wearable inertial measurement units and executed three activities (drop landing, drop jump, and modified acceleration–deceleration) within each area. Peak tibial accelerations (m/s 2 ) were compared between areas within field types for each activity using t tests (α = 0.05). Peak tibial accelerations were significantly higher ( p < 0.05; d = 0.36 and d = 0.61 for natural turfgrass and synthetic turf, respectively) in low force reduction areas on both field types (natural turfgrass = 201.0 ± 7.1 m/s 2 and synthetic turf = 248.0 ± 8.7 m/s 2 , mean ± SE) during the drop landing activity compared to the high force reduction areas (natural turfgrass = 182.3 ± 5.9 m/s 2 and synthetic turf = 220.5 ± 6.4 m/s 2 ). Peak tibial accelerations were significantly higher in low force reduction areas during the initial landing of the drop jump on natural turfgrass (178.9 ± 6.1 and 202.9 ± 6.1 m/s 2 for high and low force reduction area, respectively; p < 0.01; d = 0.61), but not synthetic turf ( p = 0.95; d = 0.01). No differences were detected between areas or field types with the second landing of the drop jump or modified acceleration–deceleration activities. These findings suggest that within-field variability affects biomechanics of athletes when performing certain athletic maneuvers, which has important implications on sports field management.