Because shorter calcaneal tuber length leads to greater Achilles stretch, more kinetic energy is converted to elastic energy, translating into better overall running economy.

A projection on the calcaneum bone called the calcaneal tuber is narrow and positioned downward relative to other lateral projections on the bone.

Calcaneal tuber and Achilles Tendon: Studies have explored the calcaneal tuber, the posterior half of the calcaneus bone, as a correlate for Achilles tendon length and have found correlation between calcaneal tuber length and Achilles tendon length.