In running, what provides the forward momentum compared to walking?

In running, the swinging leg and arm are crucial for generating forward momentum. As a runner lifts one leg and swings it forward, it helps to propel the body into the next stride. This dynamic movement increases the force and speed at which the body moves compared to walking, where the leg movement is generally more gradual and less forceful.

The swinging arm complements this by creating a counterbalance to the leg movement, which helps maintain stability and rhythm. The coordination of these upper and lower body movements enhances the efficiency of running by allowing for a more powerful push-off from the ground, resulting in greater forward propulsion.

In contrast, when walking, the overall mechanics focus more on a continuous transfer of weight with lesser emphasis on the explosive forward motion that occurs in running. The roles of other factors like the stance leg or body lean, while important, do not play as significant a role in driving momentum compared to the dynamic action of the swinging leg and arm.