Differences between forefoot and heel strike?

Question 1

What does a flatter foot cause?

Answer 1

Greater plantarflexion and knee flexion.

This distributes impact force over greater area than heel alone - cushioning impact.

Greater knee flexion = absorption of impact energy now done by muscle-tendon structures.

Question 2

Other differences?

Answer 2

Initial contact force is greater barefoot (due to shoe compression).

Peak forces similar.

Loading rate smoother for BF.

Greater plantarflexion torque required when barefoot - increasing load on calf/Achilles tendon.

Calf muscles not used to eccentric loading - can lead to soreness (quads are used to it). Can eventually lead to accumulative damage issues.

External forces act differently.

Reduced stride length - increased knee flexion/plantarflexion at touchdown/

Increased stride rate.

Question 3

How do external forces act differently on bones and joints from barefoot running?

Answer 3

Bones slowly adapt to external loads.

Adaptations occur mainly during childhood. Ability to restructure reduces with age.

BF may cause adverse stresses on bones.