Floor Reaction Force Heel Strike

The ground reaction force is distributed across the whole of the area of contact between the feet and the floor.

Floor reaction force heel strike. Control of one or more of these floor reaction forces is a viable means of controlling the alignment and or phasic motions of the foot ankle complex throughout the stance phase thereby preventing injury. The definition offered by perry 11defines heel strike initial contact as the moment when the foot just touches the floor. This is the ground reaction force generated when heel strike running in shoes. It is synonymous with the stride length.

The gait cycle is the time interval or sequence of motions occurring between two consecutive initial contacts of the same foot figure 14 1. All the elements of the muscle mesh intersected by the cross section plane contributed to the longitudinal force. For example if heel strike is the initial contact the gait cycle for the right leg is from one heel strike to the next heel strike on the same foot. The contact area is much smaller than the area of the base of support.

In forefoot striking the collision of the forefoot with the ground generates a very minimal impact force with no impact transient. At the instant of heel contact there is zero force between the foot and the floor due to the fact that the heel strike is defined the moment when contact is generated but there is no force production at that time instant. At the end of the heel strike and the loading response steps the longitudinal force inside each thigh s muscle was computed. By eliminating the heel strike the runner has eliminated the impact peak and the initial slope of the rising force is now lower.

While this definition is appropriate for normal gait it does not describe the typical heel strike in many impaired populations. Loading rate has decreased. Figure 1 21a shows the contact area when standing barefoot on both feet. This force sends a shock wave up through the body via the skeletal system.

Notice that this force trace has the impact transient characteristic of heel s. Ankle dorsiflexion weakness results in a lack of heel strike and decreased floor clearance. This leads to an increased step height and prolonged swing phase.