Background: Current guidelines for pulmonary rehabilitation (PR) recommend resistance training of the lower limb muscles. The 1RM is a maximal volitional strength test that can assess quadricep muscle strength. However, previous estimates of the MID of 1RM have been completed in small cohorts.
Aim: To provide estimates of the MID of 1RM of knee extension in patients with COPD in response to PR.
Methods: 1RM and core PR outcomes were measured before and after an eight-week outpatient PR programme. Distribution-based methods were used to estimate the MID: standard error of measurement (SEM), minimum detectable change at 95% confidence (MDC95), 0.5 standard deviation.
Results: The baseline characteristics and response to PR of 727 patients are in Table 1. Following completion of PR there were significant improvements in 1RM of 13.0 (7.0, 20.5) kg and core PR outcomes. Mean (range) MID estimates of 1RM was 5.0 (2.1 to 7.3) kg.
Conclusion: In COPD, the mean MID estimate in response to PR for 1RM is 5.0kg.
Table 1: Baseline characteristics and response to PR
| Variable | Baseline characteristics | Response to PR | p-value |
| Age (years) | 70 (9) | - | - |
| Sex (Male: n (%) | 414 (57%) | - | - |
| FEV1 (% predicted) | 53 (20) | - | - |
| BMI (kg/m2) | 27.3 (6.2) | - | - |
| Number of PR sessions attended | 13 (3) | - | - |
| MRC | 3 (1) | -1 (-1,to -1) | <0.001 |
| 1RM (kg) | 32.0 (20.0, 52.0) | 13.0 (7.0, 20.5) | <0.01 |
| 5STS (sec) | 11.44 (9.33, 14.07) | -1.6 (-3.3, -0.5) | <0.01 |
| ISW (m) | 280 (169) | 57 (52 to 63) | <0.001 |
| CRQ-Total | 78.1 (79.0) | 31.2 (4.1 to 58.4) | 0.024 |