Reliability of a test measuring transversus abdominis muscle recruitment with a pressure biofeedback unit

摘要

Background There are indications that segmental stabilising exercises (SSEs) are effective in the treatment of low back pain. The evaluationof successful training in SSE performance in patients requires a reliable outcome measure. The PRONE test gives an indication of the activityof the transversus abdominis muscle. Performed in prone lying using a pressure biofeedback unit, it has been used as an aid to training andto assess the subject's ability to perform SSEs correctly.Objectives To evaluate inter-observer and test-retest reliability of the PRONE test.Design Repeated measures by three observers on 2 days.Setting Department of Physical Medicine and Rehabilitation, Ludwig-Maximilian University, Munich, Germany.Participants Forty nurses (39 females and one male), aged between 24 and 62 years, with at least one episode of low back pain.Main outcome measures During the test, movement of the abdominal wall was monitored by measuring a change in pressure duringmuscle contraction termed 'abdominal hollowing'. Defined observation and palpation criteria were verified by the observers to ensure correctexecution of the test.Methods Participants were tested on two separate days. On the first day, Observer A performed two similar test sets, each with four exercises.On the second test day, Observers B and C conducted one test set each.Results This study found an intra-class correlation coefficient (ICC) of 0.47 [95% confidence interval (CI) 0.20 to 0.67] for inter-observerreliability, and an ICC of 0.81 (95% CI 0.67 to 0.90) for test-retest reliability. Kappa values and the limits of agreement were also calculatedwith similar results.Conclusions For this subject group, the PRONE test had relatively low inter-observer reliability but, as may be expected, higher test-retestreliability. It is suggested that by providing visual feedback, the PRONE test may enhance patients' insight into their deep abdominal musclerecruitment and thereby increase their motivation to exercise.