Escape From Grab Using Finger Lock.

Escape from lapel grab or chest push using a low kick to the tibia and finger locks.

In general, it takes an impact of 218 pounds (98kg) to fracture/break the tibia, this is reduced by using a smaller surface area to impact on the bone. However, with your opponent advancing and you kicking with focus and power this is very achievable even with the flat of your foot, the finer art is to control your kick to annul the attack, unbalance, and take control of your attacker.