Evaluation of equine locomotion during different degrees of experimentally induced lameness. II: Distribution of ground reaction force patterns of the concurrently loaded limbs.

The research article discusses a study on how various degrees of induced lameness in horses affect their biomechanics and alter the distribution of the ground reaction forces across their limbs. The analysis used force plate and high-speed film data of six horses to observe the compensatory mechanisms employed to manage lameness in a forelimb or a hindlimb.

Methodology

• The study used a set of six walking horses as subjects.
• Three different levels of supporting lameness were artificially induced in either a forelimb or a hindlimb with the aid of modified horse shoes.
• Force plate data and high-speed film footage were used to study the redistribution of ground reaction forces amongst the other limbs resulting from the lameness.

Findings

• The study found that during unilateral forelimb lameness, the decrease in longitudinal horizontal ground reaction force (Fy) was offset by an increase in the Fy forces of the opposite forelimb and the same-side hindlimb.
• The decrease in vertical ground reaction force (Fz) in the lame limb was compensated by an increase in the Fz forces of the other forelimb during the lame limb’s swing phase and from both the opposing and same-side hindlimbs during the lame limb’s stance phase.
• During unilateral hindlimb lameness, the decreased deceleration Fy forces were primarily countered with increased propulsion forces from the other hindlimb and minor increases of Fy forces from both forelimbs.
• The decreased Fz forces were compensated mainly through increased Fz forces from the opposing forelimb, with smaller increases from the same-side forelimb during the stance phase.
• The research shows compensatory increases in the non-lame limbs resulting in significant decreases in symmetry percentages between the forelimbs and hindlimbs during different degrees of single limb lameness.

Conclusion

• This research contributes valuable insights into the adaptive redistribution of force in horses suffering from varying degrees of lameness. The findings could be influential in developing therapeutic approaches, designing specific training regimes for rehabilitation, or improving existing ones.