Stance phase kinematics and kinetics of horses trotting over poles.

This research investigated how trotting over poles influences the movement patterns and ground forces experienced by horses. It revealed that trotting over poles increases brake force in the forelimbs but doesn’t increase peak vertical forces or limb extension, suggesting it is safe for rehabilitation purposes.

Objective and Hypothesis

• The main objective of this research was to study the kinematics (studying movement) and ground reaction forces (GRFs, forces exerted by the ground on a body in contact with it) of horses trotting under different conditions: on level ground, trotting over low poles (11 cm high) or over high poles (20 cm high).
• The researchers hypothesized that trotting over poles would result in increased peak GRFs and impulses in both the forelimbs (front legs) and the hindlimbs (rear legs), as the horse’s limbs would be lifting higher to clear the poles. Increased GRFs might be painful or harmful for horses with musculoskeletal injuries, thus this hypothesis is critical for horse rehabilitation.

Methodology

• A repeated measures experimental study was conducted using 8 horses, all of them having a normal gait (movement pattern).
• The horse’s kinematic data and GRFs were monitored while trotting on level ground and over poles, both low and high, placed approximately one meter apart.
• A repeated measures ANOVA analysis was used for comparisons among the different conditions, with statistical significance set at P < 0.05.

Results

• When trotting over poles, the only increased GRF component was peak forelimb braking GRF. This means the force generated by the front legs while slowing down increased.
• Forelimb vertical and braking impulses increased and the transverse impulse (sideways force) changed from being directed medially (towards the middle) to laterally (outwards).
• There were no changes recorded in extension of the metatarsophalangeal (main joint of the rear foot) and metacarpophalangeal (main joint of the front foot) joints when trotting over poles.

Conclusions

• Since trotting over poles didn’t increase peak vertical forces or extension of major limb joints, researchers concluded that this exercise doesn’t increase loading on musculoskeletal tissues, making it as safe as trotting on level ground.
• This finding supports the use of trot poles in horse lameness rehabilitation for horses exhibiting symmetrical movement.
• Generation of laterally directed forelimb transverse forces suggests that trotting over poles could involve the use of forelimb adductor muscles, those that pull the limb towards the center of the body.