Kinetics and kinematics of the passage.

The research article studies how specific dressage exercises impact the distribution of load on a horse’s limbs, and how during a specific movement called ‘passage’ the load shifts towards the horse’s rear. The impact on the horse’s limbs, measured in force and timing, remains similar as in trot.

Objective and Methodology

• The study aims to objectively assess the load acting on a horse’s limbs and the load distribution between fore and hind limbs while performing dressage exercises, particularly focusing on a movement known as ‘passage’.
• It hypothesises that the greater the horse’s level of collection – a term referring to a horse’s posture and balance, the more load is shifted to the rear end. Moreover, during the passage, the vertical load on the horse’s limbs increases due to the accentuated vertical movement of the horse’s centre of mass.
• Back and limb kinematics, vertical ground reaction force, and time parameters of each limb were assessed. Six Grand Prix dressage horses were put on an instrumented treadmill at the trot and the passage to gather necessary data.

Results

• The data showed that at the passage, horses moved at a slower speed, with a lower stride frequency, and thus a higher stride impulse than at the trot.
• The relative stance duration of fore and hind limbs remained unchanged as did the suspension duration.
• The trot and the passage differed in that while the diagonal limbs impacted almost simultaneously at the trot, the hind limbs always impacted first at the passage. However, the time dissociation between landing and lift-off remained the same for both.
• The stride impulse increased in both fore and hind limbs during the passage. Despite this increase, peak vertical forces remained unchanged due to the extended stance durations in both the fore and hind limbs.
• Within a stride, the loading shifted from the forelegs to the hindquarters.
• Despite the increased limb impulses, peak forces acting on the limbs remained similar to those observed at the trot due to prolonged stance durations.

Conclusions

• The study concluded that the passage closely resembles the trot, based on the observed intra-limb timing.
• The higher degree of collection in the passage resulted in a pronounced shift in impulse towards the hindquarters.
• An understanding of load distribution between fore and hind limbs in relation to different riding techniques is crucial for preventing wear-and-tear on the horse’s musculoskeletal system.