Frontal Plane Moments Do Not Accurately Reflect Ankle Dynamics during Running

in Journal of Applied Biomechanics
Restricted access

Purchase article

USD  $24.95

Student 1 year subscription

USD  $87.00

1 year subscription

USD  $116.00

Student 2 year subscription

USD  $165.00

2 year subscription

USD  $215.00

The ankle joint has typically been treated as a universal joint with moments calculated about orthogonal axes and the frontal plane moment generally used to represent the net muscle action about the subtalar joint. However, this joint acts about an oblique axis. The purpose of this study was to examine the differences between joint moments calculated about the orthogonal frontal plane axis and an estimated subtalar joint axis. Three-dimensional data were colected on 10 participants running at 3.6 m/s. Joint moments, power, and work were calculated about the orthogonal frontal plane axis of the foot and about an oblique axis representing the subtalar joint. Selected parameters were compared with a paired t-test (α = 0.05). The results indicated that the joint moments calculated about the two axes were characteristically different. A moment calculated about an orthogonal frontal plane axis of the foot resulted in a joint moment that was invertor in nature during the first half of stance, but evertor during the second half of stance. The subtalar joint axis moment, however, was invertor during most of the stance. These two patterns may result in qualitatively different interpretations of the muscular contributions at the ankle during the stance phase of running.

Biomechanics Laboratory, University of Massachusetts, Amherst, MA 01003

Dept. of Human Movement Sciences, University of Wisconsin–Milwaukee, PO Box 413, Milwaukee, WI 53201.