Longitudinal changes in selected physical capabilities: muscle strength, flexibility and body size

Objectives: first, to record, in a representative sample of older men and w omen, longitudinal changes in (i) maximal voluntary strength of the handgri p muscles, (ii) maximal range of movement in the shoulder joint and (iii) b ody weight and skeletal size; second, to explore associations between the c hanges in muscle strength and both customary physical activity and health o utcomes. Design: longitudinal analyses of survivors measured at baseline, and 4-year and 8-year follow-ups. Participants: 350 survivors of a random sample originally aged 65 and over. Results: over 8 years average loss of body weight was slight but significan t at about 2 kg (less than 5%). Loss of shoulder range was negligible, whil e loss of muscle strength was significant at about 40 N (less than 2% per p ar). Demispan remained stable across all three points of measurement. These mean values concealed substantial variation in the rate of loss of strengt h, which was twice as fast in the older groups, especially in the women. Th ese losses could not be attributed to worsening health, although this was o bserved. All the respondents had at least two chronic health problems at th e 8-year stage. For the changes in handgrip strength, reduced reported habi tual use of the handgrip muscles and increased symptoms of anxiety and depr ession were significant independent covariates in addition to age and time (all P< 0.0001). Conclusion: there are significant independent associations between the loss of muscle strength in old age and both decline in physical activity and in crease in depression scores. This is strongly suggestive of causal limits a nd confirms the need to encourage physical activity and control depression in order to maintain strength and function in old age.