Document Type : Full Research Paper

Authors

• Ehsan Rashedi ¹
• Mohammad Reza Nassajian ²
• Bahman Nasseroleslami ³
• Mohammad Parnianpour ⁴

¹ PhD Candidate, Mechanical Engineering School, Sharif University of Technology

² MSc student, School of Mechanical Engineering, Sharif University of Technology

³ PhD Candidate, Bioengineering Unit, University of Strathclyde

⁴ Associate Professor, Mechanical Engineering School, Sharif University of Technology Professor, Department of Information and Industrial Engineering, Hanyang University - Ansan, Gyeonggi-do

Abstract

Human motor system is organized for execution of various motor tasks in different and flexible ways. This is mainly achieved by the way that CNS uses the redundancy in musculoskeletal system. The kinetic redundancy in human musculoskeletal systems is a significant property by which CNS achieves many complementary goals. Following the definition and role of uncontrolled manifold for movement kinematics, the kinetic redundancy concept is explored in mathematical terms. The null space of the kinetically redundant system when certain joint Moment and/or Stiffness are needed is derived and discussed. The mathematical methods have already been developed and applied to a simpler planar model. However in this paper, the aforementioned concepts were illustrated, using a 3-dimensional 3- degree of the freedom biomechanical model of spine with 18 anatomically oriented Hill-type-model muscle fascicles. The results can shed light to the interaction mechanisms in activation patterns of muscles, seen in various tasks and exertions and can provide a significant understanding for future studies and clinical practices related to low back disorders. 

Keywords

• Redundancy
• Central nervous system
• Null space
• Lumbar region
• Musculoskeletal system

Main Subjects

• Biomechanical Motor Control / Motor Control of Human Movement
• Musculoskeletal Systems Modeling