HPW Biomechanics

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1 HPW Biomechanics ~ via ~ January 31, 213 To: Attn: From: Subject: I-Roc Debbie Chapman Janet S. Dufek, Ph.D. Research Scientist Additional Footwear Evaluation Information Following submission of our August 23, 212 report and subsequent conversations, we agreed to performing one additional footwear comparison test. We agreed to test one individual walking at preferred speed +1% (3.3 mph) wearing: 1) I-Roc (I), 2) traditional outsole shoe (Trad), and 3) barefoot (BF). This female individual (53 years, 1.65m, 47.6 kg) then wore the shoes daily for 8 weeks. A second measurement session was conducted, following the accommodating period. Methods The experimental protocol was followed as reported in our August 23, 212 report. Evaluation of the data included comparing walking performance at baseline versus following accommodation (8 wks) for the I-Roc condition. Correlated t-tests were used for this comparison, and level of significance was set at α=.5. Results The results, summarized in Figures 1-7, indicate that thigh range of motion (Figure 1), knee joint range of motion (Figure 2), and lumbar back flexion-extension range of motion (Figure 4) were significantly reduced during the support phase following accommodation, while leg impact significantly increased (Figure 5). There were no ankle angle range of motion, toe, or heel clearance differences observed. Exploratory statistical techniques were used to examine shoe x time relationships. The techniques used are not traditional, since trials were assumed to be randomly distributed. Embracing this assumption, 2 (time) x 3 (shoe) analysis of variance (ANOVA) techniques were HPW Biomechanics; Page 1

2 Thigh Range of Motion Hip_baseline Hip_8wks Figure 1. Thigh range of motion during the support phase of walking Knee Range of Motion Knee_baseline Knee_8wks Figure 2. Knee joint range of motion during the support phase of walking. HPW Biomechanics; Page 2

3 Ankle Range of Motion Ankle_baseline Ankle_8wks Figure 3. Ankle joint range of motion during the support phase of walking Lumbar Back Range of Motion Back_baseline Back_8wks Figure 4. Lumbar back joint range of motion during the support phase of walking. HPW Biomechanics; Page 3

4 Leg Impact Impact (g's) Leg Impact_baseline Leg Impact_8wks Figure 5. Maximum leg acceleration during the support phase of walking. Swing Phase Minimum Toe Clearance Height (m) Toe_baseline Toe_8wks Figure 6. Minimum toe clearance with respect to the ground during the support phase of walking. HPW Biomechanics; Page 4

5 Height (m) Swing Phase Minimum Heel Clearance Heel_baseline Heel_8wks Figure 7. Minimum heel clearance with respect to the ground during the support phase of walking. used to examine what effects, if any, the accommodation period (time) had on the selected performance measures. Thigh range of motion was significantly different at 8 weeks for all shoe conditions with Trad > I > BF. No differences were identified for knee joint function. Ankle joint range of motion decreased over time for Trad, with no other ankle joint differences observed. Back range of motion was significantly reduced over time for I and Trad. In addition, back range of motion was significantly less for BF versus I and Trad at baseline. After accommodation time, range of motion of the back was significantly greater than I and BF. Leg impact was different across all footwear conditions after accommodation, with Trad > I > BF. Heel clearance at baseline was significantly lesser for BF versus I and Trad. Following accommodation, heel clearance was significantly greater for Trad vs I and BF. No differences were observed for toe clearance. Summary The results for this exploratory footwear accommodation study suggest that the individual did modify walking kinematics wearing I following an 8-week accommodation period. The most dramatic observed result was that of back motion. The participant exhibited lesser low back motion after the accommodation period, producing a pattern of motion similar to walking BF. Knee and thigh range of motion decreased. Also, heel clearance became similar to BF, with Trad heel clearance being greater than that observed for I or BF. HPW Biomechanics; Page 5