Multi-segment spine and hip kinematics in asymptomatic individuals during standardized return from forward bending versus functional box lifting.

Clinically, sagittal spinal mobility is objectively assessed by forward bending range of motion (ROM) tests such as the modified-Schober test (m-Schober test). However, evidence comparing ROM during forward bending and daily activities is limited. In this study, a kinematic model including six spinal regions, pelvic/sacral and femur segment was used to characterize associations between m-Schober test and return from forward bending (RFB), and between RFB and lifting. No significant correlations were found between m-Schober test and lumbar ROM during RFB. Furthermore, we found significantly smaller ROM in all spinal regions during lifting compared to RFB, except in the upper thoracic spine, lumbosacral (L5/S1) and hip joints. However, we observed moderate to very strong correlations between the two movements tasks for all lumbar regions. Furthermore, cross-correlation between L5/S1 and lower lumbar spine regions showed no segmental redundancy of L5. These results suggest that an m-Schober test provides insufficient insight into lumbar mobility and that multi-segmental spine measurements should be introduced clinically. Furthermore, this study has demonstrated that RFB can be used as a reference for lumbar regions during lifting, with use of the current multi-segmental spine model and that the inclusion of L5/S1 provides more detailed information on lumbar kinematics.