Running

The running cycle

This section examines different stages of the running cycle.

The next section describes how movement patterns that may contribute to injury, are assessed and managed.

The running cycle pictured above is divided into 7 stages. When referring to the movements of the right foot (highlighted in red) the cycle starts with:

1. Initial contact - The foot comes in contact with the ground

2. Mid stance -      The body moves over the stance foot

3. Toe off -           The foot loses contact with the ground

4. Follow through - The first part of the swing phase

5. Forward swing - Mid swing phase

6. Foot descent -    Late swing in preperation for foot contact

7. Initial contact - One cycle ends with the same foot contacting the ground.

The muscle actions in each of the stages are outlined below:

In the diagrams, mucles working concentrically (i.e. shortening to create the movement) are coloured in green and muscles colured in red are working eccentrically (i.e. to decelerate the movement)

During initial contact the muscles around the ankle are decelerating the motion of the foot to the ground. The muscles around the knee are decelerating knee flexion on impact. Muscles around the hip are working to extend the hip.

During mid stance the calf muscles work to decelerate the motion of the leg over the foot and the knee and hip muscles continue the same roles thoughout this phase of stance.

In late stance, the calf and knee muscles help generate the extension force for toe off and the hip muscles work to decelerate the hip extension generated earlier.

During the early swing phase the ankle muscles work to flex the ankle for foot clearance. The knee flexion is controlled by the knee muslces and the hip muscles work to flex the hip forward.

During forward swing the muscle actions continue as previously

During this final stage of the cycle, the ankle muscles continue to hold the foot flexed in preparation for foot contact. The knee muscles work to decelerate knee extension and the hip to decelerate flexion.

Pronation and supination describes the range of motion in the foot during the running cycle.

Because of these extremes of range, the foot can act both as a ‘loose bag of bones’ for shock absorption and as a ‘rigid lever’ for propulsion.

Pronation –characterised by a low arch position, ‘unlocks’ the bones of the foot whilst supination –characterised by a high arch position, ‘locks’ the bones of the foot.

At initial contact, the hindfoot is inverted and pronation then occurs as the limb is loaded. Peak pronation of the foot occurs at 40% of stance, after which the foot begins to supinate, reaching neutral at 70% of stance. The bones of the foot now lock, causing the foot to become a rigid lever for toe off.