1 Department of Health Kinesiology and Applied Physiology, Concordia University, 7141 Sherbrooke Street W, SP-165.29, Montreal, QC, H4B 1R6, Canada.
2 Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
3 Department of Health Kinesiology and Applied Physiology, Concordia University, 7141 Sherbrooke Street W, SP-165.29, Montreal, QC, H4B 1R6, Canada. maryse.fortin@concordia.ca.
4 PERFORM Centre, Concordia University, Montreal, QC, Canada. maryse.fortin@concordia.ca.
5 Centre de Recherche Interdisciplinaire en Réadaptation (CRIR), Montreal, QC, Canada. maryse.fortin@concordia.ca.

CONCLUSION: Our findings suggest that utilizing fat-water and T2-weighted MR images are comparable for quantifying multifidus and erector spinae muscle composition but not of the psoas major. While this suggests that both methods could be used interchangeably for the multifidus and erector spinae, further evaluation is required to expand and confirm our findings to other spinal levels.