Age-Related Effects of Immediate and Delayed Task Switching in a Targeted Stepping Task

The ability to quickly adapt steps while walking is pivotal for safe mobility. In a previous study of immediate switching between the two stepping tasks, older adults (OAs) performed worse than young adults (YAs). However, it remained unclear whether this difference was due to an inability to learn the tasks or an inability to quickly switch. Therefore, this study investigated treadmill walking while performing two targeted stepping tasks in conditions with immediate task switching (ITS) versus delayed task switching (DTS). Thirty YAs (aged 26.9 +/- 3.1 years) and 32 OAs (aged 70.7 +/- 7.3 years) were randomly assigned to either the ITS (ITS_YAs and ITS_OAs) or the DTS (DTS_YAs and DTS_OAs) group. Each group repeatedly switched between Task A (easy) and Task B (difficult) and completed three blocks (ABAB). Delayed switching involved 1-min breaks between both tasks. Results showed that ITS_OAs exhibited significantly more step errors and worse step accuracy, but that DTS_OAs were able to achieve a similar performance as YAs. Our findings underline an inability for quick gait adaptation during targeted stepping tasks in OAs, but the possibility to learn when delayed switching reduces task interference. Public Significance Statement This study reveals that older adult's (OA's) ability for quick gait adaptability between two targeted stepping tasks is reduced but that they still can learn to perform both tasks equally well as young adults when delayed task switching is required. However, the OAs are slower in reaching these levels and immediate task switching interferes with the learning effects. Our findings indicate age-related changes in quick gait adaptability and motor learning performance during targeted stepping, as well as considerations for further interventional approaches in OAs.