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Orthopedic Research Online Journal

Movement Variability in Gait: Low Back Pain Kinematics and Chaos

Submission: July 17, 2020;Published: July 27, 2020

DOI: 10.31031/OPROJ.2020.07.000664

ISSN : 2576-8875
Volume7 Issue3


Introduction: Kinematic analysis has been a dominant tool for addressing the neuromuscular and proprioceptive alterations that occur in Low Back Pain (LBP) patients. Movement variability is a crucial component of this analysis. During the past years, a promising approach is the application of non-linear indices.

Objective: The aim of the study was to compare movement variability, as expressed mainly by non-linear indices, at the pelvis and lumbar between LBP patients and healthy participants during gait.

A. Participants and setting: Sixteen (16) LBP patients and thirteen (13) healthy control subjects (non-athletes) participated in the study.
Participants walked on a treadmill at different walking conditions while recorded by a 6-infrared camera optoelectronic system. Kinematic variability of pelvic and lumbar movement was analyzed using linear (standard deviation) and non-linear indices (Maximal Lyapunov Exponent- LyE and Approximate Entropy- ApEn).
B. Main outcome measures: It is expected that the LBP group will present with lower ApEn and/ or LyE values, underlying the less chaotic nature of their gait pattern. Gender differences in movement variability will also be investigated.

Results: Healthy subjects were found to have significantly greater mean values than LBP patients at seven pelvic and lumbar components in LyE, ApEn and SD. Specifically the calculated LyE at the pelvis during normal gait was proven to have a sensitivity of 92.3% and a specificity of 90% in the discrimination of healthy subjects from LBP patients. Female subjects presented with higher variability than males.

Conclusion: Healthy participants presented with higher movement variability indicating a more chaotic kinematic behavior in comparison to LBP patients. Lower variability values may be partly explained by the attempt of LBP patients to avoid painful end of range of motion positions. In this perspective non- linear indices seem to relate to qualitive characteristics of movement that need to be taken into consideration during rehabilitation.

Keywords: Low back pain; Movement variability; Gait kinematics; Maximal lyapunov exponent; Approximate entropy

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