Related Experiment Video
Updated: Aug 26, 2026

Mouse Lumbar Vertebra Uniaxial Compression Testing with Embedding of the Loading Surface
Published on: December 1, 2023
Multi-planar bending properties of lumbar intervertebral joints following cyclic bending
Daniel H K Chow1, Keith D K Luk, Andrew D Holmes
1Jockey Club Rehabilitation Engineering Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, PR China. rcdaniel@polyu.edu.hk
Objective:
To assess the changes in the multi-planar bending properties of intervertebral joints following cyclic bending along different directions.
Design:
An in vitro biomechanical study using porcine lumbar motion segments.
Background:
Repeated bending has been suggested as part of the etiology of gradual prolapse of the intervertebral disc, but the multi-planar changes in bending properties following cyclic loading have not been examined in detail.
Methods:
Porcine lumbar motion segments were subject to 1500 cycles of bending along directions of 0 degrees (flexion), 30 degrees, 60 degrees, or 90 degrees (right lateral bending). The multi-planar bending moments and hysteresis energies were recorded before loading and after various cycle numbers.
Results:
Repeated bending at 30 degrees and 60 degrees resulted in greater decreases in mean bending moment and hysteresis energy than bending at 0 degrees or 90 degrees. No significant differences were seen between loading groups for the change in bending moment along the anterior testing directions, but significant differences were observed in the posterior and lateral testing directions, with bending at 30 degrees causing a significantly greater decrease in bending moment in the postero-lateral directions.
Conclusions:
The change in mechanical properties of porcine intervertebral joints due to cyclic bending depend on the direction of loading and the direction in which the properties are measured. Loading at 30 degrees provokes the most marked changes in bending moment and hysteresis energy.
Related Concept Videos
Bending
In pure bending, the bending stress in a beam is calculated based on the bending moment and...
Residual Stresses in Bending
Members Made of Elastoplastic Material
As the bending moment...
Unsymmetric Bending
Plastic Deformations
General Case of Eccentric Axial Loading
Consider a member subjected to equal and opposite forces that are applied along a line that does not coincide with the member's neutral axis. In unsymmetrical bending,...
