Muscle weakness in old age, is associated with physical disability and an increased risk of falls. Progressive resistance strength (PRT) training exercises (i.e. movements performed against a specific external force that is regularly increased during training) are designed to increase strength in older people.
To assess the effect of PRT on measures of physical disability, functional limitation and impairment in older people, and identify adverse events.
We searched the Cochrane Bone, Joint and Muscle Trauma Group specialized register (to August 2002), CENTRAL/CCTR (The Cochrane Library Issue 2, 2002), MEDLINE (1966 to February 1, 2002), EMBASE (1980 to February 1, 2002), CINAHL (1982 to February 1, 2002), Sports Discus (1948 to February 1, 2002), PEDro - The Physiotherapy Evidence Database (accessed February 1, 2002) and Digital Dissertations (accessed February 1, 2002) . We also searched reference lists of articles, reviewed conference abstracts and contacted authors.
Randomised trials of PRT alone for older people (i.e. mean age of 60 or over) were included.
Data collection and analysis
Two reviewers independently assessed trial quality and extracted data. Weighted mean differences (WMD) were obtained using fixed or random effect models as appropriate. When measures with different units were pooled, standardised mean differences (SMD) were calculated. Relative risks were calculated for dichotomous outcomes.
Sixty-six trials with 3783 participants were included. Most studies were small and of poor quality. PRT had a large positive effect on strength (41 trials, 1955 participants), but there was statistical heterogeneity that was not explained by differences in study quality, participant characteristics or the exercise program. Some functional limitation measures showed modest improvements (i.e. gait speed, 14 trials, 798 participants, WMD 0.07 m/s, 95% CI 0.04 to 0.09). However, there was no evidence that PRT had an effect on physical disability when activity measures or health related quality of life measures (HRQOL) were assessed (10 trials, 798 participants, SMD 0.01, 95% CI -0.14 to 0.16 ). Adverse events were poorly recorded, but musculoskeletal injuries were detected in most of the studies that prospectively defined and monitored these events.
PRT appears to be an effective intervention to increase strength in older people and has a positive effect on some functional limitations. However, the effect of this intervention on more substantive outcomes such as measures of disability or HRQOL remains unclear. It is difficult to determine the balance of risks and benefits of PRT because adverse events have generally been poorly collected and recorded.