Differences in Stride Characteristics Between Lead and Wheel Horses in Competitive Chuckwagon Racing

Background: In Chuckwagon racing, teams of four Thoroughbreds with two lead horses in front and two wheel horses directly behind pull a 600 kg wagon around a racetrack. Our study focuses on stride parameters that have previously retrospectively predicted impending injuries. We hypothesize that in aid of the initiation of the tight figure-of-eight turn at the start of the race, the more agile lead horses gallop with higher stride frequency (SF) and reduced stride length (SL), and that differences are exacerbated in the initial accelerative race segments. Methods: Speed, SF, and SL were quantified with global navigation satellite system (GNSS) loggers over consecutive 100 m segments over 5 furlongs in sixty horses competing in Chuckwagon racing. Mixed models for SF and SL (p < 0.05, Bonferroni correction) investigated the effect of speed (fixed covariate), race segment (100 m to 1000 m), and position (lead or wheel horse) as fixed factors and their two-way interactions. Results: SF and SL were significantly affected by all two-way interactions (all p ≤ 0.025). At the average speed of 55.5 km/h, SF was 2.333 and 2.293 Hz, SL was 6.624 and 6.735 m for lead and wheel horses, respectively. Larger SF and SL differences between lead and wheel horses were found at the start and the end of the race. Conclusions: Particularly at the start and end of a Chuckwagon race, there are distinct differences in stride parameters between lead and wheel horses. Specific speed–SF–SL models for Chuckwagon lead and wheel horses might benefit from incorporating race phase.