Biomechanical analysis of INFINITY rehabilitation method for treatment of low back pain

Abstract

[Purpose] Low back pain is a pervasive problem in modern societies. Physical rehabilitation in treatment of low back pain should reduce pain, muscle tension and restore spine stability and balance. The INFINITY® rehabilitation method that is based on a figure of eight movement pattern was proved to be effective in low back pain treatment. The aim of the paper is to estimate the effect of a figure of eight motion on the L5/S1 load and lumbar spine muscle activation in comparison to other motion patterns. [Subjects and Methods] Three-dimensional model of lumbar spine musculoskeletal system is used to simulate effect of various load motion pattern induced by displacement of the center of gravity of the upper body. Four motion patterns were examined: lateral and oblique pendulum-like motion, elliptical motion and figure of eight motion. [Results] The simple pendulum-like and elliptical-like patterns induce harmonic muscle activation and harmonic spinal load. The figure of eight motion pattern creates high-frequency spinal loading that activates remodeling of bones and tendons. The figure of eight pattern also requires muscle activity that differs from harmonic frequency and is more demanding on muscle control and could also improve muscle coordination. [Conclusion] The results of the study indicate that complex motion pattern during INFINITY^® rehabilitation might enhance the spine stability by influencing its passive, active and neural components.

Keywords: Low back pain; Musculoskeletal model; Rehabilitation.

Fig. 1.

Coordinate system and musculoskeletal model. Abdominal muscles are not shown. Origin of coordinate system corresponds to projection of center of gravity of upper body to L5/S1 transversal plane.

Fig. 2.

Trajectories of upper body center of gravity and its projection into the transversal plane. (A) L-R pendulum motion, (B) AL-PR pendulum motion, (C) ellipse motion, (D) ∞ shape motion. Displacements not in scale.

Fig. 3.

Dependence between the L5/S1 spinal load and displacement of the upper body center of gravity in the transversal plane. Shaded area depicts zone of 10% deviation of spinal load from neutral position.

Fig. 4.

L5/S1 spinal load for various types of upper body center of gravity motion pattern. Inset shows trajectories of center of gravity of upper body in the transversal plane for (A) L-R pendulum motion, (B) AL-PR pendulum motion, (C) ellipse motion, (D) ∞ shape motion.

Fig. 5.

Force in the left and right segments of musculus iliocostalis (ILC) for various types of upper body center of gravity motion pattern. (A) L-R pendulum motion, (B) AL-PR pendulum motion, (C) ellipse motion, (D) ∞ shape motion.