Biokinetical analysis of the movements of the pelvic limb of the horse and the role of the muscles in the walk and the trot.

This research article discusses the study of the movements of a horse’s right hind limb during walking and trotting using cinephotography and electromyography. The study constructs a model of the stride cycle and calculates kinetic parameters, aiming to understand the role of various muscles during these movements.

Methodology

• The researchers used cinéphotography to visually record and monitor the movements of the horse’s hind limb during locomotion. This method provided accurate and detailed imagery that could be analysed in detail.
• Simultaneously, electromyography was employed to gauge muscle activity during the stride cycle. This technique measures electrical signals produced by muscle cells when they are neurologically stimulated, thus highlighting which muscles are active at different points in the cycle.
• From these two sets of data, a model of the stride cycle was constructed and kinetic parameters of the limb segments were calculated.

Findings

• A strong correlation was observed between kinetic data and the points in the stride cycle where specific muscles showed activity, confirming the interplay between muscular activation and the mechanics of locomotion.
• Analysis revealed that at the walk, the most significant forces at the limb segment’s centres of gravity occurred at the start and end of the support phase, mainly due to activity in the retractor muscles (hamstrings, gluteus medius muscles).
• In contrast, during a trot, the largest progression-directed forces arose in the middle of the support phase, predominantly resulting from muscular action.
• The study found that the gastrocnemius and cranial tibial muscles play a key role in the walk, aiding in the alignment of the load on the tibia and reducing strain caused by bending.
• The survey also identified a switch in muscle activation at the end of the support phase: the action of the rectus femoris muscle was replaced by the vastus lateralis. This rotation prevents the patella from hooking onto the medial ridge of the femoral trochlea, which could potentially impede motion.

Conclusion

• The research provides a comprehensive view of how a horse’s hind limb muscles contribute to its locomotive efficiency during walking and trotting. Not only does this new understanding improve general knowledge of equine biomechanics, but it might also enhance veterinary practices related to equine athletic training, physical therapy, and injury rehabilitation.