Why do older adults decide they are having difficulty with a task?

Objective: Previous studies have identified risk factors for decline in physical function, but they have not examined specific reasons older adults report difficulty with mobility tasks.
Design: Community-dwelling people ( n = 160) aged 59 yr and older in an observational cohort study were questioned to determine the most common cited reasons for self-reported difficulty in task performance.
Results: Mobility tasks were most often reported to be difficult (66%). The reasons cited for difficulty in low exercise tolerance tasks were task modification by method (33%) and rate (33%). For high exercise tolerance tasks, reasons cited included having to modify the rate of performing the task (20%) or the method (13%). Among those who reported difficulty with low exercise tolerance mobility tasks, >80% reported modification (odds ratio, 46.4 [95% confidence limits: 9.75, 220.51]) and 32% also report frequency change (odds ratio, 5.9 [95% confidence limits: 2.72, 12.85]) as the reason for perceiving difficulty. For those who reported difficulty performing high exercise tolerance-demanding tasks, >90% reported modification (odds ratio, 5.5 [95% confidence limits: 2.05, 14.88]) and 61% also report frequency changes (odds ratio, 3.9 [95% confidence limits: 1.93, 8.04]).
Conclusion: The findings suggest that people are able to cite specific reasons for difficulty with mobility task performance, most commonly related to task modification.