QUESTION 1 [10 MARKS]
Background
In biomechanics, practitioners are interested in measuring the forces involved during ambulation
(movement). This is called kinetics – the study of movement and the forces involved in producing it.
These forces are usually measured using a force plate as illustrated in Figure 1.
Figure 1: Experimental Set-up to measure forces involved during walking
A force plate takes advantage of Newton’s third law of motion. Consider a three-dimensional
coordinate system X, Y, and Z (Figure 1). When we step on the ground, we produce vectors of forces
in all three directions. The ground reaction force with the largest magnitude on our body is the
vertical ground reach force (VGRF), which acts along the Z direction. All other ground reaction forces
(along other directions) can be estimated from the VGRF. In biomechanics, the shape and
characteristics of the VGRF graph is frequently examined because of its importance.
(I.C. Tele 646)