P. Rantanen et F. Nykvist, Optimal sagittal motion axis for trunk extension and flexion tests in chronic low back trouble, CLIN BIOMEC, 15(9), 2000, pp. 665-671
Objective. To find the optimal height for sagittal motion axis for trunk st
rength test in chronic low back trouble.
Design. Cross-sectional study.
Background. The strength of trunk muscles of low back pain patients is decr
eased. The measured strength depends on the height of the sagittal motion a
xis but the differences between patients and controls are not known.
Methods. 114 (67 female) patients with chronic low back: trouble are classi
fied according to Quebec Task Force, 50 (31 female) patients with rheumatic
disorder, but without low back: trouble, and 33 (22 female) healthy contro
ls, no appreciable physical differences but clear differences in Oswestry s
core. Isometric trunk extension-flexion test with different heights for the
pelvic fulcrum.
Results. Force decreased in extension, increased in flexion, and torque inc
reased both in flexion and extension in every group (P < 0.001) as the fulc
rum was moved caudally. The male controls were stronger than patients with
low back trouble (P < 0.01). The female controls were stronger only if the
fulcrum was set at the hip joint level (P < 0.05). There were no difference
s between patients with rheumatic disorder and low back trouble, except in
extension if the fulcrum was at the hip joint level (P < 0.02).
Conclusions The rotation axis in trunk extension-flexion strength test shou
ld be set at the level of the hip joint. (C) 2000 Elsevier Science Ltd. All
rights reserved.