Measurement of trunk flexibility in normal subjects: reproducibility of three clinical methods

Although measurements of trunk flexibility are an important part of a clinical examination, subjective methods are usually used to assess spinal mobility. We studied three easily performed objective techniques for determining trunk flexibility (the common "fingertip-to-floor" test, the modified Schober and Moll tests, and the Loebl inclinometer method) and their interexaminer and intraexaminer reproducibility. On 3 different days, each of 25 normal subjects was tested by the same investigator. In 25 other subjects, the studies were performed by a different examiner (one of three) on each of 3 days. We recorded the following mean coefficients of variation for interexaminer and intraexaminer reproducibility of results, respectively: fingertip-to-floor, 83% and 76.4%; flexion (Schober), 6.3% and 6.6%; right lateral flexion (Moll), 11.9% and 8.9%; left lateral flexion (Moll), 10.2% and 9.5%; extension (Moll), 9.5% and 7.3%; lumbar flexion (Loebl), 9.6% and 13.4%; and lumbar extension (Loebl), 65.4% and 50.7%. Although the reproducibility of the "fingertip-to-floor" test and the Loebl extension test was poor, all other tests studied had good reproducibility. The consistency of results with repeated testing should be considered in the application of various trunk flexibility tests to clinical and research data.