Biomechanics

Proper biomechanics of the feet and limbs are very important to prevent excessive stress or strain on joints, tendons and ligaments and as such protect against injuries.

Biomechanics of the lower limb of the horse describes how structures (hoof, bone, joint, ligament, tendon, muscle) and system (lower limb) react to various forces during motion. Proper biomechanics of the feet and limbs are very important to prevent excessive stress or strain on joints, tendons and ligaments and as such protect against injuries. Corrective and therapeutic shoeing, which have gained a lot of traction in equine podiatry are based on biomechanical principles.

The stresses and strains on the tendons (superficial digital flexor and deep digital flexor), suspensory and navicular bone are mainly influenced by the sagittal flexibility of the hoof, which affects the forward (flexion) and backward (extension) movement, balancing the hoof bone within the hoof from toe to heel.

The stresses and strains on the joints and collateral ligaments are mainly influenced by the lateral flexibility of the hoof, which affect the independent up (abduction) and down (adduction) movement, balancing the hoof bone within the hoof from side to side.

The Twin™ Shoe allows for this hoof flexibility to take place as the shoe is split in two halves. The dorsal hoof angle and solar angle (coffin bone angle) are maintained between shoeing cycles as there is more even wear of heels and toe (see hoof growth, quality and shape), as such normalising biomechanics and avoiding excessive stress and strain on the joints, tendons, ligaments and navicular bone, especially towards the end of each shoeing cycle.

 
The picture above is from a hoof shod with a closed Twin shoe (comparable to a traditional shoe, i.e. not split at toe). When shod, the palmar angle of the coffin bone was 0.29°. The picture below shows the same hoof at end of shoeing cycle (after 6 weeks), due to the wear at the heels, the palmar angle was reduced to -1.06°. this is in line with the typical average decrease in palmar angle of +/- 0.40° per 2 weeks seen in horses shod with traditional shoes. This effects the biomechanics of the distal limb in a negative way. The picture above is from a hoof shod with a Twin™ Shoe (shoe split at toe). When shod, the palmar angle of the coffin bone was 0.09°. The picture below shows the same hoof at end of shoeing cycle (after 6 weeks), as the Twin™ shoe (when split at the toe) moves with the hoof, there is less wear of the heels over the shoe and the palmar angle (0.13°) stays more or less the same throughout the shoeing interval as intended by the farrier.

 

The ability of the hoof to laterally flex when shod with Twin™ Shoes keeps the joint surfaces more parallel to the ground on turns or in uneven footing, as such reducing compression of the joint on one side and stretch of the collateral ligaments and tendons on the other side. Furthermore, lateral flexibility improves the horse traction and surefootedness on uneven footing and in turns by allowing for a larger contact surface between the hoof and the ground. This has an important implication in the performance of the horse especially related to speed and agility.

Twin™ Shoes. Notice that there is less joint compression on one side and less ligament tension on the opposite side when a horse is moving on uneven footing or turns with Twin shoes vs traditional shoes.

Traditional horseshoe. Notice the increased joint compression on one side and the increased ligament tension on the opposite side when shod in traditional shoes vs Twin shoes and moving on uneven footing or turns

 

 

The Twin™ Shoe acts comparable to barefoot condition: bones, joints, ligaments and tendons will be less stressed in horses shod with the Twin™ Shoe compared to traditional shoes while improving traction, speed and agility.