Tests of spinal mobility and muscle strength in the young: Reliability and normative values

Abstract

The inter-rater reliability of 11 tests of spinal mobility and trunk muscle strength commonly used by physiotherapists was determined in 15-year-old schoolchildren with or without low back pain (LBP) identified via questionnaire. The inter-rater correlation in eight tests was strong. In the test measuring lumbar flexion with flexicurve and in the side-bending test based on skin distraction, the correlation was weaker. The inter-rater agreement in testing the dynamic strength of the abdominal muscles was also very strong; the inter-rater reliability was similar for the pupils with and without LBP. A difference was found between the examiners in testing flexibility of the hamstrings. Immediate repetition of the testing procedure improved performance in testing lumbar extension with flexicurve, in the forward- and side-bending tests, and in testing flexibility of the hip flexors and endurance strength of the abdominals. In addition, spinal mobility and strength were examined in a random sample of 14- and 17-year-old healthy schoolchildren. Sagittal mobility increased and trunk muscle strength diminished with age. In girls, endurance strength of the abdominals was diminished and in most of the tests mobility was increased compared with the boys. There was wide variation of mobility and strength by both age and gender among the schoolchildren, which complicates the interpretation of test results in clinical practice.