Trunk muscle forces and spinal loads in persons with unilateral transfemoral amputation during sit-to-stand and stand-to-sit activities

Iman Shojaei, Brad D. Hendershot, Julian C. Acasio, Christopher L. Dearth, Matthew Ballard, Babak Bazrgari

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Background: Alterations and asymmetries in trunk motions during activities of daily living, involving lower extremities, are suggested to cause higher spinal loads in persons with unilateral lower limb amputation. Given the repetitive nature of most activities of daily living, knowledge of the amount of increase in spinal loads is important for designing interventions aimed at prevention of secondary low back pain due to potential fatigue failure of spinal tissues. The objective of this study was to determine differences in trunk muscle forces and spinal loads between persons with and without lower limb amputation when performing sit-to-stand and stand-to-sit tasks. Methods: Kinematics of the pelvis and thorax, obtained from ten males with unilateral transfemoral lower limb amputation and 10 male uninjured controls when performing sit-to-stand and stand-to-sit activities, were used within a non-linear finite element model of the spine to estimate trunk muscle forces and resultant spinal loads. Findings: The peak compression force, medio-lateral (only during stand-to-sit), and antero-posterior shear forces were respectively 348 N, 269 N, and 217 N larger in person with vs. without amputation. Persons with amputation also experienced on average 171 N and 53 N larger mean compression force and medio-lateral shear force, respectively. Interpretation: While spinal loads were larger in persons with amputation, these loads were generally smaller than the reported threshold for spinal tissue injury. However, a rather small increase in spinal loads during common activities of daily living like walking, sit-to-stand, and stand-to-sit may nevertheless impose a significant risk of fatigue failure for spinal tissues due to the repetitive nature of these activities.

Original languageEnglish
Pages (from-to)95-103
Number of pages9
JournalClinical Biomechanics
StatePublished - Mar 2019

Bibliographical note

Funding Information:
This work was supported, in part, by an award ( 5R03HD086512-02 ) from the National Center for Medical Rehabilitation Research (NIH-NICHD) and the Office of the Assistant Secretary of Defense for Health Affairs , through the Peer Reviewed Orthopaedic Research Program (award # W81XWH-14-2-0144 ). The views expressed in this manuscript are those of the authors, and do not necessarily reflect the official policy or position of the U.S. Departments of the Army, Defense, nor the U.S. government. The identification of specific products or scientific instrumentation is considered an integral part of the scientific endeavor and does not constitute endorsement or implied endorsement on the part of the authors, Department of Defense, or any component agency.

Publisher Copyright:
© 2019 Elsevier Ltd


  • Biomechanics
  • Limb loss
  • Low back pain
  • Rising and sitting
  • Spinal loads
  • Trunk muscle forces

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine


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