2.3.1 The mechanics of walking: the hip-joint, the knee, and the ankle

The feet are connected to the hip through the legs. There are three joints, the ankle connects the foot to the lower leg. The knee connects the lower leg to the upper leg, and the hip joint connects the upper leg to the hip.

We shall show both a skeletal view and a schematic view:

Diagram 1: a wood mannikin with greatly simplified joints next to the skeleton, both seen from the back, showing the foot, ankle, lower leg, knee, upper leg, hip joint

Diagram 2: foot, ankle, lower leg, knee, upper leg, hip joint, hip - as simple schematic

Diagram 3: side view of the same simple schematic

Diagram 4: a wood mannikin with greatly simplified joints next to the skeleton, both seen from the back, showing the hand, wrist, lower arm, elbow, upper arm, shoulder joint

Diagram 5: a wood mannikin with greatly simplified joints next to the skeleton, both seen from the back, showing the waist and the neck

We simplify the action by focusing on the hip joint and the knee, and ignoring any movement by the ankle. This allows us to show how the weight is shifted from one foot to the other. We shall assume that the hip stays level and at right angles to the direction of motion. We also ignore any contribution by the ankle, such as for a heel to toe roll.

We further simplify the action by focusing on motion in a single plane, straight ahead of the actor, without any turns or sideways motions.