Floor Reaction Force Heel Strike

Several studies report that the vertical force passing through the foot reaches its highest peak just before lift off.

Floor reaction force heel strike.

This is the ground reaction force generated when heel strike running in shoes. Loading rate has decreased. The definition offered by perry 11defines heel strike initial contact as the moment when the foot just touches the floor. In heel striking the collision of the heel with the ground generates a significant impact transient a nearly instantaneous large force.

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 gait cycle is the time interval or sequence of motions occurring between two consecutive initial contacts of the same foot figure 14 1. By eliminating the heel strike the runner has eliminated the impact peak and the initial slope of the rising force is now lower. It is synonymous with the stride length.

At the end of the heel strike and the loading response steps the longitudinal force inside each thigh s muscle was computed. This force sends a shock wave up through the body via the skeletal system. The contact area is much smaller than the area of the base of support. All the elements of the muscle mesh intersected by the cross section plane contributed to the longitudinal force.

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. The ground reaction force is distributed across the whole of the area of contact between the feet and the floor. This leads to an increased step height and prolonged swing phase.

Notice that this force trace has the impact transient characteristic of heel s. 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. Figure 1 21a shows the contact area when standing barefoot on both feet.