A person's strength can basically be determined by four factors:
A The larger the muscle area, the greater the strength.
B nerve command ability, [for example, when angry. When in danger]
C muscle coordination, [an action always has extensor, flexor and synergic muscles, which are completed together].
D reasonable technical actions, such as punching, kicking, twisting waist, sending shoulders, etc.
Usually, when we are practicing martial arts, we always pay attention to the latter three factors at the beginning, which is why a short person like Bruce Lee has an amazing blow.