One of the most common causes of plantar fasciitis is over pronation which is a gait abnormality resulting in excessive inward rotation of the foot. The information below details the movements and pressures put on the feet when you are walking.

There are two essential aspects to walking, equilibrium and locomotion. Equilibrium is being able to walk in an upright position and keeping your balance. Locomotion is being able to maintain a rhythmic stepping motion. Muscles of the feet and legs are very important as they provide the strength to initiate and maintain movement. The most demanding task of the gait cycle is transferring your body weight onto a limb that has just finished swinging.

Phases of Gait

The gait cycle begins when one foot contacts the ground and ends when that foot contacts the ground again. Each cycle begins with the initial contact in the stance phase and moves through a swing phase until the cycle ends with the opposite foot, next to the initial contact. Stance phase accounts for approximately 60 percent and swing phase for approximately 40 percent of a single gait cycle.

Each gait cycle includes two periods when both feet are on the ground. The first period of double foot contact begins at initial contact and lasts for the first 10 to 12 percent of the cycle. The second period of double foot contact occurs in the final 10 to 12 percent of stance phase. As the stance limb prepares to leave the ground, the opposite limb contacts the ground and accepts the body's weight. The two periods of double foot contact account for 20 to 24 percent of the gait cycle's total duration.

Stance phase of gait is divided into four periods: loading response, mid stance, terminal stance, and pre swing. Swing phase is divided into three periods: initial swing, mid swing and terminal swing. The beginning and ending of each period are defined by specific events.

STANCE PHASE:

Loading response begins with initial contact, the instant the foot contacts the ground. (Normally, the heel contacts the ground first. In patients who are suffering from abnormal gait patterns, the entire foot or the toes contact the ground initially.) Loading response ends with toe off, when the opposite extremity leaves the ground.

Mid stance begins with toe off and ends when the centre of gravity is directly over the foot. (Note that this phase, and early terminal stance, the phase discussed next, are the only times in the gait cycle when the body's centre of gravity truly lies over the base of support.)
Terminal stance begins when the centre of gravity is over the supporting foot and ends when the foot contacts the ground. During terminal stance, around 35 percent of the gait cycle, the heel rises from the ground.

Pre swing begins at initial contact and ends at toe off, at around 60 percent of the gait cycle. Thus, pre swing corresponds to the gait cycle's second period of double foot contact.

SWING PHASE:

Initial swing begins at toe off and continues until maximum knee flexion (60 degrees) occurs.

Mid swing is the period from maximum knee flexion until the tibia is vertical or perpendicular to the ground.

Terminal swing begins where the tibia is vertical and ends at initial contact.

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