Three-dimensional kinematics of the XXXX spine during canter.

@entity717 @entity1641
Most research on @entity1641 kinematics has previously been performed in the walking and/or trotting animal. This is also true for the few studies on the kinematics of the @entity1641 back. These studies have, for the major part, focused on the flexion-extension movement in the sagittal plane. However, vertebrae can rotate in 3 dimensions. This study was designed to determine all 3 rotations in various segments of the vertebral column of a cantering @entity1641 . Five Dutch Warmblood @entity1641 were measured during treadmill canter (7.3 m/s). Steinmann pins were inserted into the dorsal spinous processes of 8 thoracic (T), lumbar (L) and sacral (S) vertebrae and into both tubera coxae. A set of 4 markers was rigidly attached to each pin. The marker data were used to calculate a rotation matrix that was subsequently decomposed into 3 orthogonal rotations (flexion/extension [FE]; lateral bending [LB] and @entity717 [ @entity717 ]). For the 3 rotations the variability between the @entity1641 was low for FE, slightly larger for @entity717 and largest for LB. The maximal range of motion (mean +/- s.d.) for FE, LB and @entity717 was 15.8 +/- 1.3 degrees, 5.2 +/- 0.7 degrees and 7.8 +/- 1.2 degrees, respectively. With respect to relative angles, the largest FE motion was found between L5 and S3 with values for the range of motion up to 8.6 degrees. Simultaneous rotation of successive vertebrae was observed particularly during the single support and suspension phases in the stride cycle, which increases spinal stability. For all rotations, a close correlation was observed between the timing of the @entity717 and the pro- and retraction of the limbs.
