Running is a gait that is undertaken once walking is no longer an effective or efficient mode of locomotion and can no longer provide the required speed of motion. A running gait has similarities with the walk cycle, sharing some of the distinctive phases and, in the same manner as a walk cycle, a running action can be broken into separate phases for ease of analysis.
Although the run cycle includes the passing position, the stride is replaced by a phase that distinguishes the running gait from a walk cycle. This is the suspended phase. This phase is the point in the run cycle at which the figure has both feet off the ground and is no longer supported by either foot making contact with the ground. The walk cycle is classified as having at any given point within the action at least one of the feet making contact with the ground. Once both feet are no longer in contact with the ground and the figure is in a state of suspension, the gait is classified as a run.
In addition to the passing position and the suspension phases, I include four other phases in the run cycle, breaking down the action into six distinctive parts in total. These are:
- The push
- The suspended phase
- First contact
- The passing position
- The extending phase
The role the arms play in the run remains a secondary action to what they do in a walking gait, though the contribution they make to locomotion is perhaps considerably greater in a running action. This is most evident in sprinters, particularly during that period when they first leave the starting blocks. Movement in the arms is far less extreme during a prolonged running action or a jogging action. The arm action makes a contribution to the overall action, but it is perfectly possible to run while keeping the arms at one’s side, though it is rather unnatural. The use of the arms in a run may vary throughout the action and, as already been mentioned, sprinters that accelerate quickly at the beginning of a run demonstrate a greater degree of motion in the arms than they do once they are into their stride.
The rising and falling of a figure during a running action is much more pronounced than in a walk cycle. The rise during the suspension phase is higher, and the squash results in more compression of the leg due to a bend at the knee, locating the figure slightly lower than in a walk.
As with the walk cycle, the nature of the run determines the speed at which the figure is moving. Furthermore, as with the walk cycle, the speed of the run will change with the varying length and frequency of the strides.
To aid our analysis of a running action, I have broken the movement into the key points in the cycle. For our purposes I have limited the keyframes in the illustration to four, though in the phased sequence that follows, where I provide a detailed written description of the actions at the various points of the cycle, I have included two additional phases.
FIG 5.48 Four key positions of a run cycle.