Critical Physical And Sensory Factors Related To Gait Stability And Spatiotemporal Parameters In Older Adults

Abstract

A large proportion of falls in older adults occurs while they walk. Walking stability depends on the integration of sensory inputs, proper force production and neuromuscular timing. In normal aging, degeneration of one or more of these systems occurs and may compromise walking stability, which on the other hand, has been associated with step length and gait speed. PURPOSE: To investigate physical and sensory factors that distinguish more stable walkers from poor ones in an attempt to understand critical factors in gait stability and spatiotemporal parameters. METHODS: One hundred healthy older adults walked at a self-selected speed on a flat terrain while wearing accelerometers at the head and pelvis area. Harmonic ratios of accelerations at the head and pelvis and attenuation of accelerations between head and pelvis were calculated and used to describe gait stability. Step length and gait speed were also obtained. Participants also performed physical tests including: 30 sec. chair-raise test, quadriceps and ankle dorsiflexors strength (Hand-held dynamometer), Timed Up-and-Go test (TUG); and sensory tests: sensory integration for balance (mCTSIB), and a simple reaction time test. Multiple regression analysis (stepwise) was used to determine the associations between measured factors and each of the gait stability parameters and spatiotemporal parameters. RESULTS: Head stability (R=0.351, R2=0.123, p<0.01) and attenuation (R=0.25, R2=0.06, p=0.014) were associated with one component of the mCTSIB, whereas pelvis stability was associated with the chair and TUG tests (R=0.32, R2=0.10, p=0.06). Step length and gait speed were associated with TUG test (R=0.33, R2=0.11, p=0.001 for Step length, R=0.42, R2=0.17, p<0.001 for speed). CONCLUSIONS: Pelvis stability and spatiotemporal parameters seem to be more dependent on physical capabilities such as strength and agility whereas head stability and attenuation depend more on the sensory capabilities, suggesting that proper sensory input is critical to fine tune aspects of stability such as head smoothness (harmonic ratios) and attenuation of accelerations between head and pelvis.