Background: Self-selected (SSWS) and maximum walking speeds (MWS) are frequently studied and related to multiple body systems, function, falls, and mortality. Walking at a slow speed voluntarily or measuring a range of walking speeds (WS), however, has rarely been investigated. Purpose: The aims ofthis project were to explore a proposed measure of WS adaptability called total walking speed range(TWSR), to assess the reliability and validity of slow walking speed (slowWS) as a component of TWSR, to assess if TWSR could predict function, disability or community mobility, and finally, to compare thepredictive ability of TWSR to single walking speeds. Methods: This was a cross-sectional, observational study using a convenience sample of independent community-dwelling older adults. Subjects were assessed in a single session with a battery of tests measuring common correlates of walking speed, several walking speeds, and outcome measures for function, disability (Late Life Function and DisabilityInstrument), and community mobility (Life-Space Assessment). Results: SlowWS demonstrated excellent test-retest and interrater reliability. SlowWS was only significantly correlated with TWSR, but TWSR was correlated with all study variables including the outcomes. TWSR significantly predicted function (adj. R2 = .364, p R2 = .185, p = .019), disability limitation (adj. R2 = .107, p R2 = .041, p R2 = .173, p p = .001). Conclusion: Walking at a slow speed can be reliably measured, consistent with findings for other WS. TWSR, but not slowWS, correlated with measures of body structure/function, activities, and participation and also predicted function, disability, and community mobility. However, the predictive ability of TWSR was not superior to SSWS or MWS. TWSR requires further research as a measure of walking speedadaptability, especially in relation to life-space.