Tactile Feedback Effect on Trunk-Pelvis Coordination: 1020 May 27, 3

The relationship between trunk-pelvic (TP) motions during increasing velocities while walking has received attention in the literature, with past results suggesting that increases in velocity is associated with a more out-of- phase TP relationship. Likewise, more recent research has indicated that increases in stride length (SL), rather than cadence (SF), is the cause of the increased discontinuity between the TP motions during walking. PURPOSE: Given the immediate footwear effects on gait mechanics, an aim of the present study was to understand if footwear or augmented tactile feedback altered the TP relationship during walking. METHODS: Fifty participants (25 male, 25 female) walked at a self-selected pace during four footwear conditions: barefoot (BF), insole-only (IN), a minimalist running shoe (SH), and a minimalist running shoe with the textured insole (INSH). Separate two-way repeated measures ANOVA’s with LSD post hoc analyses were performed with dependence on TP continuous relative phase mean (TP mean), TP variability (TP SD), SL, and SF, and velocity. RESULTS: Non-significant differences were found for TP mean (SH: 198°, BF: 192°, IN: 185°, INSH: 183°), TP SD (SH:36°, BF:36°, IN:37°, INSH: 41°), and velocity (SH:1.28ms-1, BF: 1.24 ms-1, IN: 1.25 ms-1, INSH: 1.26 ms-1); however, significant footwear effects were found for SL (Λ Wilks’ = 0.455, F(3,46) = 18.361, p < 0.001, η2= 0.545) and SF (Λ Wilks’ = 0.734, F(3,46) = 5.552, p = 0.002, η2= 0.266). Pairwise analyses revealed that SL was significantly longer for SH and INSH as compared to and BF and INSH. Conversely, pairwise analyses for SF revealed that only INSH was significantly lower as compared to BF and INSH. Significant gender effects were also noted for SL and SF, with females exhibiting a significantly greater height normalized SL (1, 48) = 24.991, p < 0.001, η2= 0.997) and SF (F(1,48) = 24.734, p < 0.001, η2= 0.996). CONCLUSION: Previous literature on TP coordination has largely focused on broad range velocity differences during treadmill walking, whereas the present study adjusted spatiotemporal parameters during overground walking, with little difference in walking velocity. Despite significant increases in stride length during both shod walking conditions, no significant effect on transverse plane TP coordination was found.