Neither is intended to have a circular trajectory. Boxers stride and transfer their weight forward as they deliver a blow straight out to an opponent's mid-section. But linear mechanics are inherently inefficient in developing angular velocities.
Rotational energy is very efficient in accelerating objects in a circular path.
The lower body mechanics for developing rotational energy used by Barry Bonds to hit a baseball 400 feet is almost identical to those mechanics used by John Daly to hit a golfball 1000 feet. It is important to remember that rotation around a stationary axis is generated from the ground up. The rotation of the hips and torso comes mainly from the action of both legs . Rotation of the hips is not generated from the actions of the arms or swinging of the shoulders. In fact, just the opposite is true.