Zucker-Levin A, Ling W*, McDonough A*, Oladehin A; The University of Tennessee Health Science Center, Memphis, TN. *New York University, Steinhardt School of Education, NY, USA. Azuckerlevin@utmem.edu.

PURPOSE: The purpose of this study was to determine the influence of walking speed on gait symmetry in individuals with unilateral traumatic trans-tibial amputation (TTA) while walking with their prostheses. SUBJECTS: Fifteen subjects (11 males, 4 females; average age 41.0 ± 10 years; time since amputation 10.9 ± 6.7 years) with TTA participated. Each subject had a functioning, well aligned prosthesis that was worn a minimum of 10 hours per day and walked without an assistive device. METHODS AND MATERIALS: Each participant walked at 80%, 90%, 100%, 110%, 120% and 130% of self-selected walking speed (SSWS). Walking speeds were randomized and controlled by a custom made light (tracking) system programmed by the researcher to allow the subject to alter walking speed. Subjects walked on a level surface with the GAITRite™ electronic walkway incorporated into the walking pathway. ANALYSES: Mean step length and mean step time of the intact leg and the amputated leg were determined at each walking speed for each subject. Step length symmetry (SLS) and step time symmetry (STS) were calculated by dividing the mean value obtained for the amputated leg by the mean value obtained for the intact leg. A ratio of 1.00 was considered symmetrical. Repeated measures ANOVA was performed to determine differences in STS and SLS in relation to walking speed, followed by Post-hoc Tukey to identify pair wise differences (α ≤ 0.05). The speed at which both STS and SLS occurred for each subject was determined. A paired t-test was used to compare the difference in the speeds at which STS and SLS occurred. RESULTS: The mean SSWS for the subjects was 106.5 ± 18 cm/sec (81.8 - 136.4 cm/sec). SLS and STS became most symmetric at 120% of SSWS (128.1 ± 20.9 cm/sec) with progressively more asymmetry as walking speed increased or decreased from 120% SSWS. CONCLUSIONS: Our participants with TTA walked slower than reported normal healthy subjects. The speed at which SLS and STS occurred is similar to reported SSWS of healthy, age-matched population. Our findings indicate that subjects with traumatic TTA should be encouraged to walk at a speed similar to that of normal population in order to achieve symmetrical gait pattern that is essential for efficient walking. FUNDING SOURCE: The University of Tennessee Health Science Center, Department of Physical Therapy.

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