Variation of Surface Properties over Ten Consecutive Days of Chuckwagon Racing on a Dirt Racetrack

• Surface properties and moisture quantified over ten days of Chuckwagon racing • Surface properties differ between “track” and “infield” sections • Moisture content higher in “infield” compared to “track” sections • Surface properties and moisture content vary across consecutive race days • Wet ground shows low impact, stiffness, energy restitution, high penetration depth Background: Chuckwagon races are conducted on dedicated tracks with an “infield” used for rodeo activities and a “track” used for racing. Thoroughbred horses (4 per wagon) first navigate a Chuckwagon in a figure eight maneuver around two barrels in the “infield” before galloping around the “track” and finishing the race in the “infield”. Aims/Objectives : Quantify surface properties (and their association with moisture content) for “track” and “infield”. We hypothesized that, due to different preparation, property differences would be larger between “track” and “infield” than across consecutive days and surface characteristics would be associated with moisture content. Methods : Moisture content, temperature, impact acceleration, penetration depth, stiffness, and energy restitution were measured across ten consecutive days. Mixed model analysis (P<0.05, Bonferroni correction) investigated differences between days and locations. With moisture content as fixed covariate, a second set of mixed models evaluated potential associations with surface properties. Results : Eight (of ten) surface characteristics were significantly different between locations (all P≤0.029), seven were different between days (all P≤0.047). Larger differences were found between locations for moisture content, maximum impact acceleration (at 2 and 4m/s), stiffness (at 2 and 4m/s), penetration depth (at 4m/s), and energy restitution (at 4m/s). Using moisture content as covariate, no surface characteristics showed significant differences between locations (all P≥0.139). Wetter surfaces were associated with lower impact acceleration, lower stiffness, lower energy restitution, and higher penetration depth. Conclusion s: Significant differences exist between “track” and “infield” locations for a Chuckwagon racetrack. These are largely associated with moisture content.