To put it in a nutshell , gait is not just about using your limbs etc to propel you forwards . You must first be able to get your limbs into the correct positions to perform their various roles . This is particularly true in sprinting . If the COM of a top class printer is moving at 28 mph , the trail leg/foot must be accelerated very quickly to get it out in front of the COM for the next stride in the cycle .

Interestingly , I was once stood on the inside of the track when a world class 400 m runner ran past during a training session . She must have had a peak vertical displacement of at least a foot and a half . I have wondered about that ever since .