- Specific patterns of pelvic and thorax motions are required to maintain stability during walking. This cross-sectional study explored older-adults’ gait kinematics and their kinematic adaptations to different walking speeds, with the purpose of identifying mechanisms that might be related to increased risk for falls. Fifty-eight older adults from self-care residential facilities walked on a treadmill, whose velocity was systematically increased with increments of 0.1 meters/second (m/s) from 0.5 to 0.9 m/s, and then similarly decreased. Thorax, pelvis, trunk, arms, and legs angular total range of motion (tROM), stride time, stride length, and step width were measured. Twenty-one of the subjects reported falling, and 37 didn’t fall. No significant effect of a fall history was found for any of the dependent variables. A marginally significant interaction effect of fall history and walking speed was found for arms’ tROM ( p = 0.098). Speed had an effect on many of the measures for both groups. As the treadmill’s velocity increased, the non-fallers increased their arm (15.9 ± 8.6° to 26.6 ± 12.7°) and trunk rotations (4.7 ± 1.9° to 7.2 ± 2.8°) tROM, whereas for the fallers the change of arm (14.7 ± 14.8° to 20.8 ± 13°) and trunk (5.5 ± 2.9° to 7.3 ± 2.3°) rotations tROM were moderate between the different walking speeds. We conclude that walking speed manipulation exposed different flexibility trends. Only non-fallers demonstrated the ability to adapt trunk and arm ROM to treadmill speed i.e., had a more flexible pattern of behavior for arm and trunk motions, supporting the upper-body’s importance for stability while walking.