Influence of treadmill design on rearfoot pronation during gait at different spe

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J Am Podiatr Med Assoc. 2005 Sep-Oct;95(5):475-80.

Influence of treadmill design on rearfoot pronation during gait at

different speeds.

Sajko SS, Pierrynowski MR.

Canadian Memorial Chiropractic College, Toronto, Ontario, Canada.

Understanding the dynamic function of the rearfoot is necessary for

recognizing and treating several types of mechanical foot

dysfunction. Although the motion of the rearfoot is often measured

during treadmill locomotion, the effect of different types of

treadmills on the motion of the foot is unclear.

In this study, the kinematics of the right subtalar joint in 24

volunteers walking at three speeds on two motorized treadmills were

examined. The two treadmills (a wide width and a soft surface versus

a narrow width and a hard surface) were selected to maximize motion

differences. Maximal change in angular position (positive:

supination; negative: pronation) about each volunteer's subtalar

joint axis was estimated during three gait phases: weight acceptance,

midstance, and push-off.

A factorial, repeated-measures analysis of variance determined that

the treadmill design had a significant effect on subtalar joint

position (F = 5.423; P = .029), albeit with moderate power (0.61).

Descriptively, collapsed over all speeds, the subject's feet on the

narrow/hard compared with the wide/soft treadmill showed more

pronation (0.44 degrees ), less pronation (0.46 degrees ), and more

supination (1.44 degrees ) during weight acceptance, midstance, and

push-off, respectively.

We conclude that treadmill design can affect an individual's rearfoot

kinematics.