Inter-rater reliability for ten maximal repetiton test with elastic resistance

Background: Patients with Chronic Obstructive Pulmonary Disease (COPD) present peripheral muscle dysfunction and quadriceps muscle strength is associated with functional capacity, quality of life and prognosis of mortality. So intervention programs aim to improve quadriceps muscle strength through resistance exercises. Elastic resistances are accessible and efficient for improving muscle strength and muscle mass for COPD patients. However, for elastic resistance, choosing the target training load is difficult because the load varies during the range of movement. Ten maximal repetitions (10 MR) test may be a good assessment to determinate the target load for resistance exercise with the elastic resistances for COPD patients. Considering that the variables are qualitative and that evaluators should be trained to perform the test, it is important to know if different evaluators are able to determinate the ideal training load using the 10 RM test. Objectives: To verify if there is inter-rater reliability for the 10 RM test. Methods: Two blind trained evaluators performed the 10 MR test with Theraband® elastic bands for 19 COPD patients. Test was performed with patients sitting in an adjustable ergonomic chair, for both lower limbs in 2 non-consecutives days. Weighted kappa was used for statistical analysis, with 95% of confidence interval (CI). Results: The inter-rater reliability was 0.82 (CI:0.68-0.96) for right lower limb and 0.72 (CI:0.52-0.93) for left lower limb. Conclusion: The knee extension 10 RM test with Theraband® elastic bands for patients with COPD proved to be reliable for different trained evaluators.