Spinal manipulation causes variable spine kinematic and trunk muscle electromyographic responses

Area of Science:

• Biomechanical analysis of spinal manipulation.
• Neuromuscular control in low back pain.

Background:

• The precise mechanism of spinal manipulation remains unclear.
• Theorized effects include alterations in spinal range of motion and trunk muscle activation patterns.

Purpose of the Study:

• To investigate the impact of spinal manipulation on trunk kinematics.
• To assess associated changes in trunk myoelectric activity in patients with low back pain.

Main Methods:

• An analytic cohort study involving 14 low back pain patients.
• Measurement of trunk kinematics and bilateral electromyogram (EMG) signals from paraspinal and abdominal muscles.
• Assessment of kinematics and EMG pre- and post-manipulation during range of motion tasks and quiet stance.

Main Results:

• No consistent population-wide kinematic or EMG changes were observed post-manipulation.
• Individual variability in response was noted, with some patients showing significant changes.
• Largest range of motion increases (>6 degrees) occurred in the sagittal plane for the most pained individuals.
• Seventeen muscles showed altered activity during quiet stance, with 16 demonstrating decreased amplitude.

Conclusions:

• Preliminary data suggest short-term effects of spinal manipulation on lumbar range of motion and dynamic electromyography.
• The response to manipulation appears highly individualized, with greater changes observed in patients experiencing more pain.
• This study contributes to understanding the biomechanical influences and functional changes associated with manipulative therapy.