Within- and between-field variability in natural turfgrass and synthetic turf is associated with differences in...

Natural turfgrass and synthetic turf athletic fields exhibit variability within and between surface types due to factors such as usage and maintenance, yet limited research has examined how this variability is associated with differences in athlete mechanical loading and perception.

This study quantified surface characteristics and athlete responses across four athletic fields, two natural turfgrass and two synthetic turf, with one high-usage and one low-usage field of each type. Surface hardness, rotational resistance, infill depth, thatch depth, and soil moisture were evaluated to characterize field conditions. Fourteen female athletes completed standardized drills while wearing Blue Trident ankle inertial measurement units (IMUs) and STATSports APEX GPS performance trackers to quantify lower-limb impact loading and running speed, respectively. Athlete perceptions of surface conditions were assessed using pre- and post-performance surveys.

Surface hardness varied significantly within and between field types (p < 0.001), with mean values of 61.3 and 69.7 Gmax for low- and high-usage synthetic turf, respectively, and 46.8 and 49.8 Gmax for low- and high-usage natural turfgrass. Harder surfaces, particularly synthetic turf, resulted in greater lower-limb impact intensity, increasing from an average intensity of 17.8 g on natural turfgrass to 20.7 g on synthetic turf across drills. Within synthetic turf fields, certain higher-hardness areas produced "high-intensity" ankle IMU classifications, indicating increased mechanical loading in these regions. Survey results indicated that athletes rated the low-usage natural turfgrass field most positively, reporting higher surface quality and less negative impact on performance, while both synthetic turf fields received more positive ratings than the high-usage natural turfgrass field. Overall, results demonstrate that spatial and between-field variability in surface properties can influence athlete loading and perception, highlighting the importance of considering both objective surface characteristics and athlete experience when evaluating athletic field safety and performance.