THREE-DIMENSIONAL MULTI-SEGMENTED SPINE JOINT REACTION FORCES DURING COMMON WORKPLACE PHYSICAL DEMANDS/ACTIVITIES OF DAILY LIVING.

OBJECTIVE

The quantification of inter-segmental spine joint reaction forces during common workplace physical demands.

BACKGROUND

Many spine reaction force models have focused on the L5/S1 or L4/L5 joints to quantify the vertebral joint reaction forces. However, the L5/S1 or L4/L5 approach neglects most of the intervertebral joints.

METHODS

The current study presents a clinically applicable and noninvasive model which calculates the spinal joint reaction forces at six different regions of the spine. Subjects completed four ambulatory activities of daily living: level walking, obstacle crossing, stair ascent, and stair descent.

RESULTS

Peak joint spinal reaction forces were compared between tasks and spine regions. Differences existed in the bodyweight normalized vertical joint reaction forces where the walking (8.05±3.19N/kg) task had significantly smaller peak reaction forces than the stair descent (12.12±1.32N/kg) agreeing with lower extremity data comparing walking and stair descent tasks.

CONCLUSION

This method appears to be effective in estimating the joint reaction forces using a segmental spine model. The results suggesting the main effect of peak reactions forces in the segmental spine can be influenced by task.