A study of normal locomotion requires an
understanding of both the movements and the
force actions involved. This is equally true in
appreciating the problems of pathological gait.
The gait cycle is described in terms of the
significant events which occur during both the
stance and swing phases.
The basic principles underlying the analysis
of force actions in walking are briefly described.
A simple example of force actions in the elbow
joint is considered and the analysis extrapolated
to provide a general statement regarding locomotion.
This relates to the muscle actions
required to resist turning actions at joints due
to the force effects in walking and the corresponding
forces in the joints themselves.
The conventional display of information
relating to joint actions is considered and
compared with the actual situation. “Stick
diagrams” of motion in the sagittal plane are
used to identify and discuss the actions at the
joints of the leg in walking. Comparisons are
made between this and pathological gait-in
particular that of the above-knee amputee.