Rearfoot Varus

Rearfoot Varus is when the rearfoot has a decreased amount of STJ pronation causing the calcaneus to be positioned into an inverted position.
Effects:

This leads to the foot striking the ground in a more supinated position than normal. This more supinated position requires the foot to travel a further distance to achieve necessary pronation at midfoot. This causes the medial column to slam into the ground harder than normal. This in turn fails to give the foot enough time to adequately supinate, creating a rigid lever. Inadequate supination during toe off causes a soft midfoot and can put strain on soft tissue.

If the position of the calcaneus is more inverted then this changes the pull of the

Deformities that can result secondary to a rearfoot varum include:

1. Genu Varum
2. Forefoot Valgus (caused by lateral pressure on foot). 
3. Plantar Fasciitis (caused by rapid pronation leading to high medial GRF). 
4. Hammertoes (secondary to flexor stabilization which is activated in an attempt to stablize the foot during propulsion).