Background and objective: Aging as a complex and multifactorial process involves multisystemic changes associated with physical performance with loss of functionality such as walking speed and reserve. The study established the method that best evidences the functional reserve (FR) of walking speed (FRWS) according to the incorporation of stimuli in older adults (OAs). Material and method: Analytical observational study with a sample made up of 30 OAs between 65 and 69 years, self-administered without risk, normal weight and without suspicion of depression, controlled in Centro Comunitario de Salud Familiar and Centro de Salud Familiar of Talca. The walking speed (WS) was measured by three methods: M1 (usual gait), M2 (maximum gait) and M3 (maximum gait with stimuli); to later calculate the FRWS in the AO, executed on a 10 m track that included 2 m acceleration, 2 m deceleration and 6 m centrals to measure the time in seconds it took to travel them. Results: The mean velocities of the sample in the usual, maximum and maximum stimulated methods were 1.17, 1.38 and 1.57 m/s respectively; the resulting FRs between the method differences: FR-A (M2 − M1) 0.26 m/s; FR-B (M3 − M1) 0.45 m/s and FR-C (M2 − M3) 0.19 m/s, for most of the cases and according to the corresponding order, the statistical differences were significant. Conclusion: The method that best evidenced the FRWS was through the differences in means between M3 and M1, being an objective way to verify this dimension of human movement as an expression of OA functionality.