Chronic low back pain (LBP) is a prevalent condition in older adults, being identified as a cause of disability in this population. Despite ir validity and reliability, the functional capacity tests are not often administered in patients with LBP but provide useful information related to mobility. A measurement property of the functional capacity tests that has not been investigated extensively in the LBP field is the resiveness, such as the capacity to detect changes during the intervention.

To determine the responsiveness of three functional capacity tests, the Timed Up and Go test, the 4-meter Walk test, the 5 times Sit to Stand test, and to compare with the responsiveness of the Roland Morris Disability Questionnaire (RMDQ) in older adults with chronic LBP undergoing an 8-week intervention.

This is a responsiveness study with measurement before and after an 8-week intervention. It was prospectively registered at the Brazilian Registry of Clinical Trials (RBR-9prhzng). Patients with nonspecific LBP (age ≥60) were recruited. The functional capacity tests and the RMDQ were administered at baseline and after 8 weeks. The intervention followed the recommendations from clinical practice guidelines for the management of nonspecific LBP: The responsiveness was determined by calculating the effect size (ES), correlation analysis, and the analysis of the Receiver Operating Characteristic (ROC) Curve to calculate the area under the curve (AUC).

118 older adults with chronic LBP were recruited. The RMDQ was the most responsiveness measure, followed by the Sit to Stand test. The ES for the RMDQ was large (ES= -0,74; 95%IC: -0,56; -0,92), whereas the 5 Times Sit to Stand test presented a small effect (EF= -0,45, 95%CI: - 0,26; -0,64). The Timed UP and Go test and the 4-meter Walk test small ESs (ES< 0,25). The 5 Times Sit to Stand test was the only one to show a fair correlation (0,25 < r <0,50) with RMDQ. The ROC analysis, only the RMDQ showed AUC values above the cut-off point of 0,70.

The RMDQ was responsive to an 8-week lumbar stabilization program in older adults with chronic LBP. The 5 Times Sit to Stand test was the most responsive but presented limitations with regard to the capacity to discriminate patients who recovered from those who did not recover. A possible explanation for the lack of responsiveness foto the tests may be due to the nature of the intervention, which was not focused on increasing ability and balance, components that are necessarily assessed by functional capacity tests.

Functional capacity tests are widely used to assess mobility and balance in older adults. Only the 5 Times Sit to Stand test was considered to able to detect changes in older adults who underwent an 8-week intervention program. The RMDQ was more responsive than any of the functional capacity tests.