| Travelling short or medium distances for us is easily | | | | phase, which is preswing, is preparatory for the |
| accomplished by walking, which is convenient and | | | | swing phase, starting with the last part of both leg |
| easy but needs our muscles and joints to be in good | | | | support and ending when the heel comes up on one |
| condition and to be pain free. Having enough muscle | | | | side. The swing phases (initial, mid and terminal) |
| power and sufficient joint range of movement in the | | | | manage clearance of the foot above the ground and |
| legs is necessary for efficient walking. As walking | | | | the bringing forward of the trailing limb to move to |
| progresses one leg gives the body support while the | | | | the front. |
| other swings through to be placed forward and in its | | | | Efficient gait includes aspects of shock absorption |
| turn to take weight. The swing and stance phases | | | | and energy conservation and alterations of joint |
| are the easiest way of understanding where either | | | | movement or absence of muscle power may |
| leg is at a particular point. | | | | increase the joint contact forces which can lead to |
| Achieving all the phases of gait so that you get back | | | | pathological changes in the structures abnormally |
| onto the same foot you started on is referred to as | | | | loaded. Almost 60% of the body weight is |
| the gait cycle. The duration of both feet remaining on | | | | transferred to the early stance leg in very short |
| the ground at the same time is about 10 percent and | | | | period, under 20 milliseconds. |
| one leg is standing on the ground for about 40 | | | | The leg joints absorb and control these forces as |
| percent of the time. The rest consists of the swing | | | | they act as shock absorbers and dampers. When the |
| part of the cycle as the non-weightbearing leg is | | | | leg is placed initially on the ground the forward forces |
| taken through to a position where it can again bear | | | | involved tend to make the knee bend so we resist |
| weight. As our walking speeds increase the duration | | | | this by making the knee straighter even though this |
| of the gait cycle phases reduces until there is no | | | | increases the forces through the joints. Loading |
| double support phase where both feet are weight | | | | forces are minimised by eccentric muscle action by |
| bearing at the same time, a condition known as | | | | the hip adductors and quadriceps. |
| running. | | | | Locomotion demands that we expend energy but for |
| The leg joints follow a specific and repeatable series | | | | most of us the level is low if we are healthy, going |
| of actions during the swing and stance phases with | | | | at our normal speed and walking on level ground. We |
| stance made up of five sections in the order of initial | | | | minimise the amount of energy we use in walking by |
| contact, loading response, mid stance, terminal stance | | | | choosing a preferred speed which is most efficient. |
| and preswing. Heel strike is the common name given | | | | Musculoskeletal or neurological conditions always slow |
| to initial contact but some people do not heel strike | | | | down the walking speed but do not have to increase |
| at all or transfer weight to the heel later in the phase. | | | | the energy load per unit time because patients usually |
| Heel strike allows the leg which is about to weight | | | | slow their cycle down. However, the energy needed |
| bear to take the weight but not compromise speed, | | | | to cover an identified distance can increase greatly |
| stability or shock protection. | | | | with more than three times the normal expenditure in |
| While the one leg is supporting the weight of the | | | | the case of stroke. |
| body the other leg is in swing phase. The first part of | | | | Wheelchair use allows locomotion speed to be |
| the single leg support phase is called mid stance and it | | | | maintained and can cut energy expenditure per unit |
| is during this phase that the bodyweight moves the | | | | of distance by fifty percent. Patients tend to choose |
| centre of gravity and support over the foot. The | | | | a wheelchair to get about when the amount of |
| cycle continues into terminal stance where the | | | | energy necessary exceeds a particular level, |
| supporting foot rises at the heel and then stops | | | | especially when it goes beyond three times the |
| when the opposite foot makes contact. The last | | | | normal amount of energy required. |