Dynamic stability during increased walking speeds is related to balance confidence of older adults: a pilot study

Background: Some older individuals walk slower, which may be due to decreases in mechanical stability at faster speeds or due to psychological factors like balance confidence. Research Question: What is the relationship between progressively increasing walking speeds on dynamic stability in older and younger adults and how does this relationship interact with balance confidence in older adults? Methods: 10 young adults and 14 older adults were recruited for this pilot study. Individuals completed the Activities Specific Balance Confidence Scale. Individuals walked on a treadmill in a robotic device that interfaced with individuals at the pelvis allowing all degrees of freedom of movement and provided safety for a loss of balance. Participants walked at speeds from 0.4 - 2.0m/s in 0.2m/s increments or until the participant chose not to attempt a faster speed. Margin of stability was assessed. Results: The ABC of older adults was lower than younger adults (89±13 vs 99±1 scores, p=0.006) and some older adults chose to stop walking before 2.0m/s (n=6). The margin of stability variability of the older adults was significantly greater than young adults in the sagittal (p=0.013) and frontal plane (p=0.007). Older adults became unstable (margin of stability<0) at a slower speed (p<0.001). For older adults, balance confidence was correlated to the fastest speed attempted on the treadmill (rho=0.85, p<0.001). However, the balance confidence and walking speed individuals became unstable were not significantly correlated. Finally, a significant relationship was found between the zero crossing and the fastest speed attempted (rho=0.60, p=0.022). Significance: Some older adults with lower balance confidence were less willing to experience instability at faster walking speeds on the treadmill, even though the external threat to balance was low. Lower balance confidence and a sense of loss of stability may be factors in decreased willingness to experience activities for some older adults.