B.C. Krevitz, J.J. Hannigan, S.A. Dean, C.D. Pollard

Oregon State University-Cascades, Bend, OR

Maximal shoes, defined by increased cushioning in the midsole, have become increasingly popular among the older adult population. Knee osteoarthritis and associated knee pain are prevalent in the aging population. A considerable amount of research has examined the influence of footwear on biomechanical risk factors associated with knee osteoarthritis (OA). However, very little is known about the influence of maximal footwear on these biomechanical factors. PURPOSE: To compare joint kinematics, kinetics and ground reaction forces between maximal and traditional footwear during walking in older adults. METHODS: Participants consisted of 15 active female older adults (50-70 years old). Three-dimensional lower extremity biomechanics were captured during walking using an eight-camera motion capture system and two force platforms in two shoe conditions: maximal footwear (rearfoot: 37 mm, forefoot: 33 mm) and traditional footwear (rearfoot: 33 mm, forefoot: 23 mm). Variables of interest included frontal plane ankle and knee kinematics and kinetics, peak vertical ground reaction forces, and the instantaneous loading rate of the vertical ground reaction force. These variables were compared between shoes using a repeated measures ANOVA and an alpha-level of .05. RESULTS: To date, data for 5 of 15 participants has been analyzed. Participants exhibited greater eversion at initial contact in the maximal shoe (-5.2 ± 4.6°)compared to the traditional shoe (4.7 ± 3.6°, p= .046). In addition, the peak external knee varus moment was higher in the maximal shoe (0.60 ± 0.25 Nm)compared to the traditional shoe (0.49 ± 0.23 Nm, p= .022).There were no differences between the peak vertical ground reaction forces and the instantaneous loading rate between the two shoe conditions (p < .05). CONCLUSION: There is a strong consensus in the literature that increased knee varus moments are associated with an increased risk of knee OA. Therefore, our finding of increased knee varus moments in the maximal shoe condition suggests that the maximal shoe may place older females at increased risk of knee OA. Further data analysis is needed to confirm this result.

Research supported by the Layman Research Fellowship Grant at Oregon State University - Cascades.

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