Measurement of Low Back Mobility, Isometric Strength and Isoinertial Performance with Isostation B-200 Triaxial Dynamometer: Reproducibility of Measurement and Development of Functional Indices

The reproducibility of measurements with the triaxial lumbar dynamometer Isostation B-200 was measured in 61 volunteers with or without low back problems. Both for the intra- and interrater measurements the reproducibility was good (r = 0.76-0.89) for lateral flexions and almost as good (r = 0.76-0.87) for the sum of all ranges of motion (SROM). The corresponding reproducibilities were excellent (r = 0.82-0.99) for the isometric strength and good (r = 0.60-0.90) for isoinertial flexion-extension repetition test parameters in the main (primary axis) direction. A number of parameters were combined into three functional indices: the reproducibility for "power" and "work" index was good (r = 0.76-0.94) in both intra- and interrater conditions, whereas for "movement" index it was somewhat weaker (r = 0.53-0.87). It is concluded that parameters: lateral flexions, SROM, isometric strength, and functional indices (power and work) are reproducible enough to use in further studies.