Gait characteristics of younger-old and older-old adults walking overground and on a compliant surface

Background: Walking across unstable surfaces disturbs normal stability and efficient strategies must be used to avoid falls. This study identified age-related changes in gait during unstable surface walking. Method: Eight healthy younger-old adults (YOG, mean age, 68.6 years) and eight healthy older-old adults (OOG, mean age, 82.1 years) were assessed. Both groups performed the Timed Up and Go Test (TUG) and walked on a rigid and on a compliant surface while kinematic data were obtained. Results: The OOG needed more time to complete the TUG test compared to YOG (F-1,F-14=5.18; p=0.04). The gait speed, stride length and vertical displacement of the foot were similar for both groups, but they were slower (F-1,F-14=5.64; p=0.03) when walking on the compliant surface. The knee and hip range of motion on the sagittal plane (F-1,F-14=191.9; p<0.001 and F-1,F-14=36.4, p<0,001, respectively) increased on the complaint surface but no group effect was found. The displacement of upper trunk on the frontal plane was similar between groups (F-1,F-14=2.43; p=0.14) and conditions (F-1,F-14=1.15; p=0.3). The OOG had greater displacement of the pelvic segment on the frontal plane than the YOG (F-1,F-14=4.9; p=0.04) mainly for the complaint surface. Conclusion: Older-old individuals have slower TUG test and greater displacement of the pelvic segment on a compliant surface. More challenging tasks and/or environment should be used for gait assessment and intervention of older adults with risk of falls.