A systematic review including 27 studies was abstracted in DARE. Spinal compression as indicated by intra-discal pressure and spinal shrinkage does not appear significantly different between the squat lifting technique (with the back as erect as possible) and the stoop lifting technique. Net moments and compression forces based on model estimates were found to be equal or somewhat higher in the squat lifting. Only when the load could be lifted from a position in between the feet did squat lifting cause lower net moments. Shear forces and bending moments acting on the spine appeared lower in squat lifting.
Comment: The quality of evidence is downgraded by indirectness (no clinical outcomes) and limitations in review methodology.