Increased Attentional Focus on Walking by Older Adults Limits Maximum Speed and Is Related to Dynamic Stability

Abstract

<b><i>Background and Purpose:</i></b> Older adults with lower balance confidence demonstrate a reduced willingness to experience instability as the task of walking becomes more challenging (i.e., walking with a faster speed). However, the specific reason why is not known. The purpose of this study was to investigate the extent to which capacity of increasing walking speeds relates to the attentional requirements (i.e., automaticity) of walking. <b><i>Methods:</i></b> Sixteen young (31 ± 5.85 years) and 15 older participants (69 ± 3.04 years) began walking on a treadmill at 0.4 m/s, and speed was increased by 0.2 m/s until the participant either chose to stop or reached a speed of 2.0 m/s. Sixty steps were collected at steady-state speed for each walking trial. Kinematic data were collected, and the margin of stability in the anterior direction (MOS<sub>AP</sub>) at heelstrike was quantified for each step. The timed up and go (TUG) and TUG dual (TUG<sub>dual</sub>) task were performed, from which an automaticity index (TUG/TUG<sub>dual</sub> × 100) was calculated. Older individuals were grouped based on whether they did or did not complete all walking speeds (i.e., completers [<i>n</i> = 9] or noncompleters [<i>n</i> = 6]). The fastest walking speed attempted (FSA), automaticity index, and MOS<sub>AP</sub> were compared, and correlations were assessed between the FSA/MOS<sub>AP</sub> and the automaticity index. <b><i>Results:</i></b> A significant difference was identified in an average MOS<sub>AP</sub> at heelstrike between older completer and noncompleter groups (<i>p</i> < 0.001). Further, older adults with lower automaticity index choose to stop walking at lower speeds (<i>p</i> = 0.001). The FSA was positively correlated with the automaticity index (ρ = 0.81, <i>p</i> < 0.001). Finally, the average MOS<sub>AP</sub> at FSA and the automaticity index were also negatively correlated (<i>r</i> = −0.85, <i>p</i> < 0.001). <b><i>Conclusion:</i></b> Older adults with lower automaticity of walking choose to stop walking at speeds before they completed all walking speeds, which may relate with increased attentional demands required to maintain dynamic stability at higher walking speeds. Given that these were otherwise healthy adults, the combination of FSA and an automaticity of walking may help to identify individuals who should be considered for an assessment to identify walking problems.

The validity and reliability of the OneStep smartphone application under various gait conditions in healthy adults with feasibility in clinical practice

“…The gait speed of 0.8 m/s was selected as this is a speed that is predictive of poor clinical outcomes [ 21 ]. The speed of 2.0 m/s was selected as this is a speed used to determine limits of dynamic stability in older adults [ 22 ]. The self-selected gait speed with dual task was defined as ambulating at the designated self-selected speed while performing the serial seven test, requiring the participants to count down from 100 backward by sevens.…”