Gait mechanics during acceleration (AC), at steady state (SS), and during deceleration (DE) are used to assess functional ability, mobility, and falls risk in older adults. Walking mechanics, which are often assessed in a room of limited length, differ during these phases. The purpose of this study was to determine minimal distances needed for AC and DE during normal and fast self-selected walking speeds, and to determine a minimal walkway length that would include six SS steps in a group of older adults. Method: 34 independent, older adults (9 men and 25 women) mean age 82.1(±6.6) yr walked across a 10 meter indoor walkway. They walked two lengths as practice, then two lengths each at normal and fast speeds while being videotaped from the side. Step lengths were biomechanically determined for the second trial at each speed by projecting the image onto a wall-mounted scale to measure the foot placements, which were converted to life units using a linear scale that had been videotaped in the plane of walking. Step lengths were chosen as the indicator of SS variability as they are more variable than foot timing sequences. Coefficients of variation (CV) were calculated for each subject for every consecutive three steps (CV1:steps 1,2,3; CV2:steps 2,3,4; etc) at both speeds for the full walkway distance. CVs of <.07 represented SS walking. Percentile ranks were computed for AC, DE, and average SS step length distances. The minimum recommended walkway length to accommodate individuals at or below the 90th %ile for an analysis of six SS steps was calculated as follows: Min walkway length (6 steps) = {P90 AC distance + 6 (P90 average SS step length) + P90 DE distance} Results: One subject's data was excluded from analysis, as she did not establish a SS pattern at normal or fast speeds. The following was determined based on the 33 remaining subjects: Min walkway length normal speed = {2.17m + 6 (0.72m) + 1.80 m} = 8.29m Subjects needed 4.6 and 4 AC and DE steps, respectively. Min walkway length fast speed = {3.23m + 6 (0.76m) + 1.85 m} = 9.64m Subjects needed 5 and 2.6 AC and DE steps, respectively. It appears that for normal and fast speed walking 4 and 5 meters respectively are used in non SS walking suggesting these additional distances be allowed if SS walking is to be studied. Keyword(s): measurement/evaluation, older adult/aging issues, research