| Travelling short or medium distances for us is easily | | | | and preswing consists of the last part of the double |
| accomplished by walking, which is convenient and | | | | support phase before the leg goes on into swing. |
| easy but needs our muscles and joints to be in good | | | | There are three swing phases, initial, mid and terminal, |
| condition and to be pain free. Having enough muscle | | | | which allow the leg to be brought forward for the |
| power and sufficient joint range of movement in the | | | | next heel strike and for the leg to clear the |
| legs is necessary for efficient walking. As walking | | | | intervening ground. |
| progresses one leg gives the body support while the | | | | Energy conservation and shock absorption are |
| other swings through to be placed forward and in its | | | | important parts of efficient gait. The joint contact |
| turn to take weight. The swing and stance phases | | | | forces can be increased if there are joint restrictions |
| are the easiest way of understanding where either | | | | or loss of muscle power, leading to structural |
| leg is at a particular point. | | | | pathologies in the abnormally loaded areas. Sixty |
| The process of going through all the stages and | | | | percent of the bodyweight loads extremely quickly |
| getting back onto the same foot again is known as | | | | onto the leg in the early stance phase, taking only |
| the gait cycle. Both feet are down on the ground for | | | | twenty milliseconds. |
| about 10% of the gait cycle, with a single down on | | | | The leg joints absorb and control these forces as |
| the ground for about 40% percent overall. The | | | | they act as shock absorbers and dampers. When the |
| remainder is made up of the swing part of the cycle | | | | leg is placed initially on the ground the forward forces |
| as the legs are being brought through to be placed | | | | involved tend to make the knee bend so we resist |
| down on the ground again for the next step. As | | | | this by making the knee straighter even though this |
| walking gets faster the duration of these phases of | | | | increases the forces through the joints. Loading |
| the gait cycle reduces and when we start running | | | | forces are minimised by eccentric muscle action by |
| then there is no double support phase when both | | | | the hip adductors and quadriceps. |
| legs are on the ground at the same time. | | | | Walking always takes energy but these demands are |
| The stance and swing phases consist of a precise | | | | relatively small for normal adults walking on the level |
| and repeatable series of movements during normal | | | | at their natural speed. We each tend to have a |
| locomotion, with five different stages of stance | | | | naturally chosen walking speed which minimises the |
| phase. These are initial contact, loading response, mid | | | | amount of energy we expend. All muscular or |
| stance, terminal stance and preswing, although initial | | | | neurological conditions slow walking speed down but |
| contact is often referred to as heel strike. Heel strike | | | | do not necessarily increase the amount of energy |
| is a slight misnomer as some people do not heel | | | | used per time due to the slower cycle. Even though |
| strike or at least weight transfer to the heel later in | | | | the energy cost per unit time may not change the |
| the phase. Heel strike allows shock reduction and | | | | actual cost of getting along a particular distance can |
| maintenance of stability and speed whilst | | | | increase markedly, for instance more than 3 times |
| accomplishing weight transfer to a new leg. | | | | the normal in stroke. |
| The swing phase occurs as the other leg supports | | | | Using a wheelchair cuts energy requirements per |
| the weight of the body, taking the body centre of | | | | distance by 50% and allows speed to be maintained. |
| support to be placed over the foot in what is | | | | The choice of using a wheelchair may be made by a |
| referred to as mid stance which initiates the phase of | | | | patient when the amount of energy to get across a |
| single leg support. The supporting foot lifts at the | | | | certain distance exceeds a certain level, often when |
| heel as the cycle progresses into terminal stance, a | | | | the load exceeds 300% of what would be normally |
| phase which stops when heel strike is obtained on | | | | required. |
| the other foot. The swing phase is about to start | | | | |