In this chapter we examine terrestrial locomotion (walking and running) from both descriptive and quantitative points of view. The study of locomotion has long been an important part of the field of biomechanics. Although not strictly “locomotion,” we also consider the dynamics and kinematics of jumping.

Jumping

Standing jump

We begin by considering the standing vertical jump, since it is the easiest jump to analyze. A standing jump can be divided into two phases, defined as follows (Fig. 10.1).

1. Push-off: starting from a crouch, the jumper pushes against the ground with his/her legs until the feet leave the ground.

2. Airborne: from the moment that the feet leave the ground until the maximum elevation of the center of gravity is reached.

Analysis of the standing jump is most easily carried out if we neglect changes in posture and body orientation while jumping, and consider only the elevation of the center of gravity. We therefore define:

1. c = distance the center of gravity is lowered, measured with respect to the elevation of the center of gravity at the instant the feet leave the ground.

2. h = maximum elevation of the center of gravity, measured with respect to the same reference datum.

3. z = vertical location of the center of gravity, measured positive upwards from the floor.

4. v = vertical velocity of the center of gravity, measured positive upwards.