Effects of chronic low back pain on local dynamic stability and intersegment coordination during repetitive lifting

Abstract

Background: Despite advancing developments in modern medicine and growing knowledge pertaining to spinal disorders, chronic low back pain (CLBP) remains the leading cause of disability worldwide. This is partly due to varying movement dysfunctions observed in people with CLBP. Although previous research has shown that people with CLBP exhibit altered motor control strategies, the literature is characterized by inconsistent findings. Thus, improved empirical assessment methods, such as intersegment coordination and local dynamic stability, have the potential to improve measurement of and detection of neuromuscular deficiencies exhibited in people with CLBP. While intersegment coordination and local dynamic stability measures have been used extensively in healthy people, there is a scarcity of research that has applied these measures to assess people with CLBP. Therefore, this thesis primarily aimed to compare movement and stability between CLBP and healthy people using intersegment coordination and local dynamic stability assessment. Methods: Twelve participants with CLBP and 12 healthy participants performed one set of repetitive deadlifts for 35 repetitions with a dowel rod and one set with a barbell loaded with 15% of their bodyweight for 35 repetitions. Inertial Measurement Units (IMU) were used to measure trunk and lower limb kinematic parameters. Local dynamic stability and intersegment coordination were then calculated from the kinematic data and compared between the groups using a 2-factor repeated measures ANOVA. Results: Significantly greater local dynamic stability of the hip and knee was observed in the CLBP group compared to the healthy control group. The CLBP group also reported increased low back pain immediately after completion of the loaded and un-loaded lifting trials. No differences in intersegment coordination or coordination variability were observed between two groups. There were no differences observed in local dynamic stability and intersegment coordination when lifting with a load compared to lifting with no-load for both groups. Conclusion: Our findings suggest that the significantly greater local dynamic stability of the hip and knee exhibited by the CLBP group may be mediated by pain avoidance. Local dynamic stability assesses both spatial and temporal characteristics of a lifting cycle, thus potentially providing greater insight into the differences in motor control of people with CLBP than intersegment coordination analysis. This thesis has shown that local dynamic stability is a measure which has potential clinical utility for monitoring changes in stability over time.

Date of Award	2023
Original language	English