Question

Describe the different phases of the gait cycle and describe each of the muscles used in each cycle.

Answer 1

The gait cycle is the sequence of movements or locomotion and hence one cycle of gait consists of one foot being on the ground and it continues in the motion until the heel moves and prepares for next step or movement. Hence there is propulsion or movement in direction of motion and hence involves propelling the centre of gravity. Hence in short, one gait cycle is when there is movement from one point to another through contact with ground and in preparation for next step by same foot.

Different phases of Gait cycle are:-

The two primary phases of gait cycle are as follows:-

1. Stance phase – In this phase, the foot first touch the ground and the movement ends as the same foot lifts in a motion to leave the ground. This consists of around completion of 60% of the gait cycle. In this phase, the leg weight is carried and accepted by the body weight and supported by single limb.

The stance phase again is divided into sub-phases which are:-

• Heel strike – This is the first phase of the stance phase and is the beginning of the initial contact. It is defined by short period which starts as foot touches the ground and within this there is 3- degree flexion along with full extension of knee. In this the knee flexion increases and is followed by increase in the plantar flexion of heel which is supported by contraction of tibialis anterior as the quadriceps contracts. This also causes rectus femoris contraction.

• Foot flat – In this as the body prepares for its motion, the impact is absorbed by the foot and is supported by hip moving into extension. This leads to contraction of the adductor magnus as well as the muscles of the gluteus maximus.

• Midstance – In this type of motion, there is contraction of the gluteus medius muscle and hence leads to flexion to extension of knee. The tricep surae muscles also contracts and as the body starts to move, there is forward propulsion.

• Heel off – In this position, the heel of the foot starts to leave the floor and there is hyperextension of the hip. In this, there is supination of the ankle and flexing of the plantar. .

2. Swing Phase – This phase is the one which starts after the stance phase ends and is present between toe off and heel strike phase. It can be categorized as acceleration and deceleration phase. As the acceleration phase starts, the toe pushes up into midswing and in the deceleration; it goes from mid-swing to heel strike.

• Toe Off - This is also known as the pre-swing phase where the extension of the hip is restricted and there is flexing of knee by 35 to 40 degrees

• Early swing - In the early swing phase, the hip extends by 10 degree and this takes place due to contraction of the iliopsoas muscles.

• Midswing – This the type there is flexion of hip by 30 degrees through adductors contraction and it also leads to the contraction of tibialis anterior muscles. This is followed by even contraction of the quadriceps muscles.

• Late swing – This is the last phase which consists of hip flexion of around 25 – 30 degrees and leads to formation of locked extension.