Lumbar spinal moments in chronic back pain patients during supported lifting: a dynamic analysis.

OBJECTIVES

The main objective of this study was to test the hypothesis that peak L4/L5 moments (torque) placed on the lumbar spine by chronic back pain subjects are reduced using pain-reducing postural adaptations. A secondary objective was to determine the relation between lumbar moments while lifting and self-reported ratings of lower back pain.

STUDY

DESIGN

Cohort using seven men with a history of chronic lower back pain. An inverse dynamic model was used to calculate L4/L5 forces and moments while performing five trials each of two lifting styles. Subjective ratings of lumbar back pain were taken before and after the lifts.

RESULTS

Significant (p < .001) differences were found between lifting postures on peak L4/L5 net reaction moments. Two distinct lifting profiles emerged characterized by the amount of lumbar spinal extensor musculature involved. Significant (p < .05) increases in pain were found after a bowed-back lifting style.

CONCLUSIONS

Peak L4/L5 net reaction moments were less (spine extensor loading) for a lifting posture that produced lower levels of self-reported lower back pain. The dynamic model proved reliable and useful for future study of the pathomechanics of lower back pain.