Walking is a very easy and convenient way of travelling short distances but it relies on a good joint and muscular system and an absence of pain. The efficiency of walking relies on good joint ranges of motion and sufficient muscular power in the lower limb musculature. As we move forward in walking one leg provides the support for the body while the other one moves through to take its place. Gait is divided most simply into swing and stance phases which indicate what position the leg is in at any one time.
The process of going through all the stages and getting back onto the same foot again is known as the gait cycle. Both feet are down on the ground for about 10% of the gait cycle, with a single down on the ground for about 40% percent overall. The remainder is made up of the swing part of the cycle as the legs are being brought through to be placed down on the ground again for the next step. As walking gets faster the duration of these phases of the gait cycle reduces and when we start running then there is no double support phase when both legs are on the ground at the same time.
The stance and swing phases consist of a precise and repeatable series of movements during normal locomotion, with five different stages of stance phase. These are initial contact, loading response, mid stance, terminal stance and preswing, although initial contact is often referred to as heel strike. Heel strike is a slight misnomer as some people do not heel strike or at least weight transfer to the heel later in the phase. Heel strike allows shock reduction and maintenance of stability and speed whilst accomplishing weight transfer to a new leg.
With one leg supporting the bodyweight the other limb is going through the swing phase. The body moves the centre of support over the foot in what is known as mid stance, the initial part of the phase of single leg support. Terminal stance occurs next as the heel of the supporting foot rises from the ground and finishes as the other leg makes heel strike and begins to support weight. Preswing is really a preparation for the swing phase and begins with the last part of the both leg support phase, finishing when the foot is raised to begin swing. Foot clearance above the ground and the forward motion of the leg to engage another step are the function of the swing phases of initial, mid and terminal swing phases.
Energy conservation and shock absorption are important parts of efficient gait. The joint contact forces can be increased if there are joint restrictions or loss of muscle power, leading to structural pathologies in the abnormally loaded areas. Sixty percent of the bodyweight loads extremely quickly onto the leg in the early stance phase, taking only twenty milliseconds.
The leg joints absorb and control these forces as they act as shock absorbers and dampers. When the leg is placed initially on the ground the forward forces involved tend to make the knee bend so we resist this by making the knee straighter even though this increases the forces through the joints. Loading forces are minimised by eccentric muscle action by the hip adductors and quadriceps.
The energy demands of walking are significant but not large in normal adults who walk at their own speed on the level and we choose our typical walking speed to minimise the energy expenditure. Walking speeds are always slowed down when a patient suffers from neurological and musculoskeletal conditions but because the gait cycle is slowed down in these cases the energy expenditure per unit time may not be increased. However, in stroke for example, the energy demand for accomplishing a specific distance can rise markedly, to more than three times the normal level.
Using a wheelchair cuts energy requirements per distance by 50% and allows speed to be maintained. The choice of using a wheelchair may be made by a patient when the amount of energy to get across a certain distance exceeds a certain level, often when the load exceeds 300% of what would be normally required.
The process of going through all the stages and getting back onto the same foot again is known as the gait cycle. Both feet are down on the ground for about 10% of the gait cycle, with a single down on the ground for about 40% percent overall. The remainder is made up of the swing part of the cycle as the legs are being brought through to be placed down on the ground again for the next step. As walking gets faster the duration of these phases of the gait cycle reduces and when we start running then there is no double support phase when both legs are on the ground at the same time.
The stance and swing phases consist of a precise and repeatable series of movements during normal locomotion, with five different stages of stance phase. These are initial contact, loading response, mid stance, terminal stance and preswing, although initial contact is often referred to as heel strike. Heel strike is a slight misnomer as some people do not heel strike or at least weight transfer to the heel later in the phase. Heel strike allows shock reduction and maintenance of stability and speed whilst accomplishing weight transfer to a new leg.
With one leg supporting the bodyweight the other limb is going through the swing phase. The body moves the centre of support over the foot in what is known as mid stance, the initial part of the phase of single leg support. Terminal stance occurs next as the heel of the supporting foot rises from the ground and finishes as the other leg makes heel strike and begins to support weight. Preswing is really a preparation for the swing phase and begins with the last part of the both leg support phase, finishing when the foot is raised to begin swing. Foot clearance above the ground and the forward motion of the leg to engage another step are the function of the swing phases of initial, mid and terminal swing phases.
Energy conservation and shock absorption are important parts of efficient gait. The joint contact forces can be increased if there are joint restrictions or loss of muscle power, leading to structural pathologies in the abnormally loaded areas. Sixty percent of the bodyweight loads extremely quickly onto the leg in the early stance phase, taking only twenty milliseconds.
The leg joints absorb and control these forces as they act as shock absorbers and dampers. When the leg is placed initially on the ground the forward forces involved tend to make the knee bend so we resist this by making the knee straighter even though this increases the forces through the joints. Loading forces are minimised by eccentric muscle action by the hip adductors and quadriceps.
The energy demands of walking are significant but not large in normal adults who walk at their own speed on the level and we choose our typical walking speed to minimise the energy expenditure. Walking speeds are always slowed down when a patient suffers from neurological and musculoskeletal conditions but because the gait cycle is slowed down in these cases the energy expenditure per unit time may not be increased. However, in stroke for example, the energy demand for accomplishing a specific distance can rise markedly, to more than three times the normal level.
Using a wheelchair cuts energy requirements per distance by 50% and allows speed to be maintained. The choice of using a wheelchair may be made by a patient when the amount of energy to get across a certain distance exceeds a certain level, often when the load exceeds 300% of what would be normally required.
About the Author:
Jonathan Blood Smyth is a Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He specialises in orthopaedic conditions and looking after joint replacements as well as managing chronic pain. Visit the website he edits if you are looking for physiotherapists in Sheffield.
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