Kinetic Integrations Blog

Indeperpedent Subsystems With Low Back Pain

Panjabi et al. proposed a concept for understanding spinal stability, injury, dysfunction and recovery, asserting that there are three interdependent subsystems that function to stabilize the spine: the passive, active and neural subsystems:

  • The passive musculoskeletal subsystem includes the spine and its vertebrae, disks and ligaments. The spinal column is the load-bearing unit and the source of passive stiffness for stabilizing the spine.
  • The active musculoskeletal subsystem comprises the muscles attached to, or influencing the spinal column. These muscles are the source of active stiffness via their stored elastic energy and their level of activation or force.
  • The neural control subsystem is the controller. This system uses feedforward control to generate active stiffness and uses feedback control to to augment the stiffness.


The Subsystems

These three subsystems are interdependent and work together to maintain spinal stability and intervertebral motion in a healthy and unhealthy state. Damage or dysfunction in one subsystem requires the other two to compensate. For example, an injury such as disc degeneration affecting the passive musculoskeletal subsystem may decrease the inherent stability of the spine and alter segmental motion patterns. Enhancement of the neural and active musculoskeletal subsystems could then help compensate for this loss and partially restore stability of the area of the spine.


  1. Panjabi MM: Clinical spinal instability and low back pain. J Electromyogr Kinesiol 13:371-379, 2003
  2. Panjabi MM: A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction. Eur Spine J 15:668-676, 2006
  3. Panjabi MM: The stabilizing system of the spine. Part I. Function, dysfunction, adaptation, and enhancement. J Spinal Disord 5:383-389, 397, 1992
  4. Panjabi MM: The stabilizing system of the spine. Part II. Neu tral zone and instability hypothesis. J Spinal Disord 5:390-397, 1992
  5. Panjabi M, Abumi K, Duranceau J, Oxland T: Spinal stability and intersegmental muscle forces. A biomechanical model. Spine 14:194-200, 1989
  6. Panjabi MM, Krag MH, Chung TQ: Effects of disc injury on mechanical behavior of the human spine. Spine 9:707-713, 1984