Muscle Relaxation and Shear Force Reduction May Be Conflicting: A Computational Model of Seating

This paper reports new knowledge on the biomechanics of the seated posture with special emphasis on muscle fatigue and shear forces in soft tissues. The work relies on a detailed musculoskeletal model of the human body developed in the AnyBody Modeling System. The model is placed in an adjustable seat, and the influence of the seat's parameters on the necessary muscle activations and soft tissue shear forces in the buttocks are investigated. It is concluded that muscle relaxation and shear force reduction are conflicting desires that are difficult to obtain simultaneously.