Measurement of indoor physical activity at home in older adults who have difficulty performing outdoor activities is a key to documenting baseline physical activity levels to guide physical activity interventions aimed at reducing the rate of decline in mobility.
The purpose of this study was to describe indoor life-space mobility at home (LSH) and examine the association between LSH and mobility-related physical functions in older adults who have difficulty performing outdoor activities.
The participants were 20 community-dwelling older adults (mean age [SD], 76.6 [5.1] years) receiving home-care rehabilitation. Participants were assessed for LSH and physical function related to mobility. Assessments included isometric knee extensor strength, the Timed Up and Go (TUG) Test, functional status (a 13-item Motor subscale of Functional Independence Measure, the Tokyo Metropolitan Institute of Gerontology Index of Competence, and outdoor life-space mobility (life-space assessment [LSA]). Life-space mobility at home documented how far and how often participants moved from a bedroom to 4 destinations (entrance, dining room, bathroom, and toilet) at home with or without assistance during the week prior to the assessment.
Reliability of LSH was high (intraclass correlation coefficient [ICC] (1,1) = 0.80, ICC (1,2) = 0.89). Simple bivariate correlations showed a significant relationship between LSH and isometric knee extensor strength (rs = 0.59, P = .01) and TUG Test (rs = −0.74 P = .01). Life-space mobility at home showed moderate correlations with the Functional Independence Measure (rs = 0.58, P = .01) and Tokyo Metropolitan Institute of Gerontology Index of Competence (rs = 0.49, P = .03), but no significant correlation with the LSA (rs = 0.33, P = .17).
Regarding intrarater reliability, the ICCs for measuring the LSH indicated high reproducibility. The results suggest that the LSA mainly reflects outdoor life-space mobility and activity rather than indoor life-space whereas the LSH reflects indoor life-space mobility and is considered an indicator of a major decline in indoor activities and physical abilities.
The LSH concept can measure with high reliability and concurrent or discriminant validity, and it is a different concept from outdoor life-space mobility. Life-space mobility at home may be an important factor associated with physical functions related to mobility and functional status, and measuring LSH may be useful to assess current indoor life-space activity in older adults who have difficulty performing outdoor activities.