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A novel stability-based EMG-assisted optimization method for the spine

Samadi, S ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.medengphy.2018.04.019
  3. Publisher: Elsevier Ltd , 2018
  4. Abstract:
  5. Traditional electromyography-assisted optimization (TEMG) models are commonly employed to compute trunk muscle forces and spinal loads for the design of clinical/treatment and ergonomics/prevention programs. These models calculate muscle forces solely based on moment equilibrium requirements at spinal joints. Due to simplifications/assumptions in the measurement/processing of surface EMG activities and in the presumed muscle EMG-force relationship, these models fail to satisfy stability requirements. Hence, the present study aimed to develop a novel stability-based EMG-assisted optimization (SEMG) method applied to a musculoskeletal spine model in which trunk muscle forces were estimated by enforcing equilibrium conditions constrained to stability requirements. That is, second-order partial derivatives of the potential energy of the musculoskeletal model with respect to its generalized coordinates were enforced to be positive semi-definite. Fifteen static tasks in upright and flexed postures with and without a hand load at different heights were simulated. The SEMG model predicted different muscle recruitments/forces (generally larger global and local muscle forces) and spinal loads (slightly larger) compared to the TEMG model. Such task-specific differences were dependant on the assumed magnitude of the muscle stiffness coefficient in the SEMG model. The SEMG model-predicted and measured L4-L5 intradiscal pressures were in satisfactory agreement during simulated activities. © 2018 IPEM
  6. Keywords:
  7. Biomechanical model ; Electromyography (EMG) ; Forces ; Muscle stiffness ; Spine ; Constrained optimization ; Convergence of numerical methods ; Electromyography ; Ergonomics ; Potential energy ; Stability ; Stiffness ; Bio-mechanical models ; Equilibrium conditions ; Generalized coordinates ; Musculoskeletal model ; Stability requirements ; Muscle
  8. Source: Medical Engineering and Physics ; Volume 58 , 2018 , Pages 13-22 ; 13504533 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S1350453318300912