Comparison of limb kinematics between collected and lengthened (medium/extended) trot in two groups of dressage horses on two different surfaces.

Background: Dressage horses are often asked to work in lengthened paces during training and competition, but to date there is limited information about the biomechanics of dressage-specific paces. Preliminary work has shown increased fetlock extension in extended compared with collected paces, but further investigation of the kinematic differences between collected, medium and extended trot in dressage horses is warranted.

Objectives: Investigation of the effect of collected vs. medium/extended trot on limb kinematics of dressage horses.

Study Design: Prospective kinematic evaluation.

Methods: Twenty clinically sound horses in active dressage training were used. Group 1: Ten young horses (≤6 years) were assessed at collected and medium trot and Group 2: Ten mature horses (≥9 years) were assessed at collected and extended trot. All horses were evaluated on two different surfaces. High speed motion capture (240 Hz) was used to determine kinematic variables. Fore- and hindlimb angles were measured at mid-stance. Descriptive statistics and mixed effect multilevel regression analyses were performed.

Results: Speed and stride length were reduced and stride duration increased at collected compared with medium/extended trot. Lengthened trot (medium/extended trot) was associated with increased fetlock extension in both the fore- and hindlimbs in both groups of horses. Changes were greater in mature horses compared with young horses. Shoulder and carpus angles were associated with forelimb fetlock angle. Hock angle was not significantly influenced by pace. Surface had no effect on fetlock or hock angles.

Main Limitations: Only 2D motion analysis was carried out. Results may have differed in horses with more extreme gait characteristics.

Conclusions: Medium/extended trot increases extension of the fore- and hindlimb fetlock joints compared with collected trot in both young and mature dressage horses, respectively.