Whether you are conscious of it or not, your feet move your body forward to where you want to go at the pace you want to take. They use the least amount of energy by moving in as straight a line as possible, and adjust their movement to avoid pain if you have a painful foot condition. They act as shock absorbers for your body. And unless you are hopping, your feet alternate on the ground as you go forward with the lower one propelling the one in mid-air forward.
The alternating of your feet as you walk happens in two phases:
- The ‘Stance phase’ is when the foot is on the ground. It comprises about 60% of the walking cycle. For part of the stance phase both feet will be on the ground for a period of time.
- The ‘Swing phase’ occurs when one foot is on the ground and one in the air.
Even during the ‘Stance phase’ a single foot goes through five sub-stages:
- Heel strike
- Early flatfoot
- Late flatfoot
- Heel rise
- Toe off.
The defining difference between walking and running is that during running there is a period of time when both feet are off the ground (the ‘Float’ phase). Also, as running is associated with greater speeds, the forces that go through the foot when it lands can be substantially greater than during walking; it is often 4-5 times body-weight during running and even up to 6-7times body-weight during sprinting.