Aim: To identify physical fitness factors associated with occurrence of disability requiring long-term care and reviewing physical fitness factors to identify threshold values at which future care risk is expected to rise rapidly.
Methods: This prospective cohort study included 74-88-year-old women who were living at home and who reported no disability in activities of daily living. The subjects completed 16 physical fitness tests, assessing walking ability, muscular strength, flexibility, agility and balance, and participated in a follow-up interview 6 years later.
Results: Among the 60 subjects who were not disabled at baseline and who participated in the 6-year follow up, 28 subjects were certified to have a disability necessitating long-term care after 6 years. Among the 16 physical fitness tests, 13 measures showed a significant association with the necessity of care. Maximum walking time and ankle dorsiflexion range of motion (ROM) were identified as main physical fitness factors associated with later necessity of care using a multiple logistic regression model. After adjustment for age, each subject's probability of occurrence of disability necessitating care was calculated using a logistic equation. The probability rose rapidly to more than 80% when 10 m maximum walking of 74-78-year-old subjects was 10 s. For 80-88-year-old subjects, the probability rose rapidly to more than 80% when the time was at 9 s. As ankle dorsiflexion ROM narrowed, the probability rose gradually.
Conclusion: Ability to walk rapidly is an indicative main physical fitness marker for predicting the independence of elderly women.