What is life-space mobility and how does it relate to physical capacity and outdoor walking in older adults?

To describe life-space mobility and determine how it relates to physical capacity measures (PCMs; walking endurance, walking speed, leg strength, balance) and outdoor walking in older adults with difficulty walking outdoors. 

A secondary analysis of data from a randomized controlled trial of 173 older adults with difficulty walking outdoors was conducted. LSM was measured using the Life-space Assessment (LSA). PCMs included the 6-minute and 10-metre walk test (comfortable and pace), 30-second sit-to-stand, and the mini-BESTest. The relationship between PCM scores and LSA total score was examined using Spearman correlations and backward stepwise regression modelling adjusted for age and sex. The relationship between outdoor walking and LSA total score was examined using Spearman correlation. 

Mean participant age was 74.6±7.1 years and 73.4% were females. Mean LSA total score was 64.6±20.2 (range=19.5-110.0). Less than 50% reported going out of town (LSA level 5) in the past 4 weeks. PCM scores and weekly outdoor walking hours each had a fair and positive correlation with LSA total score (PCM scores: ρ=0.42-0.45, p0.001; outdoor walking hours: ρ=0.28, p0.01). The final regression model including walking speed, leg strength, and balance explained 31% of LSA total score variance.

PCM scores and outdoor walking time both relate to LSM in community-dwelling older adults with difficulty walking outdoors, though outdoor walking time has a weaker correlation with LSM.

LSM is a novel concept that describes one’s frequency and independence in moving through different spaces, with strong predictability on adverse outcomes in older adults. Older adults with difficulty walking outdoors have lower LSM than the average older adults, characterized by lower scores on the LSA. Understanding how physical factors affect LSM may help physical therapists direct rehabilitation efforts. For older adults with difficulty walking outdoors, physical therapists could consider using a combination of 10-metre walk test (comfortable speed), 30-second sit-to-stand, and the mini-BESTest together to infer life-space mobility from a physical capacity perspective.