The naturally sound foot is one that is biomechanically functional and able to do what it was inherently designed to do
Simply stated, the naturally sound foot is one that is allowed to expand as it makes contact with the ground and to contract as it goes into flight.
EXPANSION – The foot hits the
ground and expands, making
contact first with the hoof wall then
almost simultaneously with the sole,
frog and bars.
CONTRACTION – The foot comes
off the ground and then re-contracts
back to its original shape.
When you put a shoe on a horse's foot, it goes on the foot when the foot is in its contracted state. Then, when the horses foot hits the ground or bears weight with the shoe on, it is unable to expand because it has been locked into its contracted state.
BARE FOOT – The foot expands
and contracts freely, allowing the full
biomechanics of the foot to operate.
SHOD – The foot is unable to
expand and contract freely and is
locked in an oxygen-starved
contracted state.
When the hoof capsule expands, it creates a vacuum inside the hoof capsule because the expansion creates a larger area inside the hoof capsule. This vacuum in the capsule sucks blood from the upper part of the leg into the hoof capsule. When the foot goes back to flight and the capsule re-contracts, it forces the blood out of the hoof capsule and up the leg, on its way back to the heart.
IF YOU STOP THE BIOMECHANICS OF THE FOOT, YOU WILL NO LONGER HAVE A NATURALLY SOUND FOOT.
If the blood can no longer be pumped through the foot freely by the expansion and contraction process, the foot will suffer from the lack of blood support and will become oxygen starved. The structures in the hoof capsule will suffer from a lack of healthy, healing oxygenated blood, and the down hill spiral begins.
As if the lack of blood support wasn’t enough, when a horse is shod 80% of the shock absorption value of the foot is also lost. The horse's foot was never meant to be supported strictly by the hoof wall as it is when a horse is shod. The wall, the bars, the frog, the laminae, and the expansion and contraction process all play an important, if not equal, part in the shock absorption of the foot.
