Running

We will begin the following section with a description of the normal gait pattern during running as it is necessary to understand the normal running gait before discussing the influence of pathology or orthotic intervention. Recall that during normal walking there are two single support stance phases divided by a double support stance phase in a single gait cycle. Ipsilateral toe off normally occurs at approximately 62% of the gait cycle and heel strike follows at approximately 0% of the following gait cycle. Figure 4 (Novachek, 1998) compares the differences in incidences and phases of gait in walking, running and sprinting. In running there is no double support stance phase. There are two single support stance phases separated by a section of the gait cycle where there is no contact with the ground whatsoever called double float. In running the single support phases change with respect to the speed at which the individual is running. In a study that looked at both running and sprinting toe off occurred at approximately 39% of the gait cycle while running and 36% while sprinting. World class sprinters have been observed to toe off as early as 22% of the gait cycle (Novachek, 1998).

For further information on the biomechanics of running, please refer to our Learning Guides Section

Figure 4 - Comparison of phases and incidences of gait in walking, running and sprinting, (Novachek, 1998)

In walking and running there is one similar area of major power generation. This is the plantarflexor power generation at the ankle used to propel the body forward. As the speed of the walking or running increases so does the magnitude of the power. An area of difference between running and walking is power absorption/generation at the knee. In walking the power absorption/generation at the knee is somewhat negligible with the most notable areas being eccentric contraction (absorption) at loading response for shock absorption and again at terminal swing to slow the leg to prepare for initial contact. In running there is a period of power absorption and a period of power generation. Power is absorbed as the leg reaches full extension in terminal swing and into the period which could be considered loading response (similar to walking). Power then starts being generated at the knee once the COM reaches its lowest point within the stance phase, this generation continues throughout the rest of stance and into the second double float phase (Novachek, 1998). It is interesting to note that the power generation at the knee decreases in sprinting when compared to running. It is said that this is due to the decreased ROM at the knee in sprinting as the body maintains a position with a greater anterior trunk and pelvic lean. In sprinting power generation is mainly reverted back to being the responsibility of the plantarflexors at the ankle (Novachek, 1998). What does this say about brace design for a sprinter versus a long distance runner? What would you think would be the expected feedback from the patient in either case?

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