Exercise therapy has been shown to be effective in decreasing pain and improving function for patients with recurrent low back pain (LBP). Research on the mechanisms that trigger and/or underlie the effects of exercise therapy on LBP problems is of critical importance for the prevention of recurring or persistence of this costly and common condition. One factor that seems to be crucial within this context is the dysfunction of the back muscles. Recent pioneering results have shown that individuals with recurring episodes of LBP have specific dysfunctions of these muscles (peripheral changes) and also dysfunctions at the cortical level (central changes). This work provides the foundation to take a fresh look at the interplay between peripheral and central aspects, and its potential involvement in exercise therapy. The current project will draw on this opportunity to address the following research questions: What are the immediate (after a single session) and the long-term effects (after 18 repeated sessions) of exercise training on: (1) back muscle structure; (2) back muscle function; (3) the structure of the brain; (4) and functional connectivity of the brain. This research project also aims to examine whether the effects are dependent on how the training was performed. Therefore a specific versus a general exercise program will be compared.
Although the cause of persistent non-specific LBP remains unknown, structural and functional alterations of the brain and paravertebral muscles have been proposed as underlying mechanisms. As it is hypothesized that these alterations contribute to, or maintain non-specific LBP, exercise therapy is a key element in the rehabilitation of reoccurring LBP. Specific training of sensorimotor control of the lumbopelvic region (i.e. specific skilled motor training) has shown to decrease pain and disability in patients with LBP, but has not been found superior to other forms of exercise training regarding improvements in clinical outcome measures. On the other hand, this type of training seems to differentially impact the recruitment of the back muscles compared to general exercise training. However, research using multiple treatment sessions and including follow-up outcome assessments is scarce. Furthermore, it is unknown if improvements may be attributed to measurable peripheral changes in the muscle and/or central neural adaptations in the brain. The primary aim of this study is to examine the short and long-term effects of specific skilled motor control training versus unspecific general extension training on pain, functional disability, brain structure/function and muscle structure/function in recurrent LBP patients. Method: In this double-blind, randomized controlled clinical trial 62 recurrent LBP patients will be randomly allocated (1:1) to receive either specific skilled motor training (i.e. the experimental group) or general extension training (i.e. control group). Each training group will receive 13 weeks of treatment, during which a total of 18 supervised treatment sessions will be delivered in combination with an individualized home-exercise program. Both groups will first receive low-load training (i.e. at 25-30% of the individual's repetition maximum, sessions 1-9) followed by high-load training (i.e. at 40-60% of the individual's one repetition maximum, sessions 10-18). Primary outcome measures include: LBP-related pain and disability (RMDQ, NRS and Margolis pain diagram), lumbar muscle structure and function (Dixon MRI and mf-MRI) and brain structure and function (MRI, DTI and fMRI). Secondary measures include: lumbopelvic control and proprioception (thoracolumbar dissociation test and position-reposition test), trunk muscle activity (RAM and QFRT) and psychosocial factors, including measures of physical activity (IPAQ-LF, SF-36), pain cognitions and perceptions (PCS, PCI and PVAQ), anxiety and depression (HADS), and kinesiophobia (TSK). Experimental data collection will be performed at baseline, immediately following the low-load training (i.e. after the 9th supervised treatment session), following the high-load training (i.e. after the 18th supervised treatment session), and at 3 months follow-up. Experimental data collection will comprise of magnetic resonance imaging of the brain and trunk muscles, clinical assessments assessing muscle function, and a battery of questionnaires evaluating psychosocial factors.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
62
Participants allocated to the skilled motor training group will receive sensorimotor training of the intrinsic muscles of the lumbopelvic region, namely the multifidus, transversus abdominis, and pelvic floor muscles.
Participants allocated to the general extension training group will receive general training exercises using the David Back equipment from the Back Unit at Ghent University Hospital
Ghent University, vakgroep revalidatiewetenschappen
Ghent, Oost-Vlaanderen, Belgium
RECRUITINGBrain macro-structure
Whole brain T1-weighted structural MRI will be acquired.
Time frame: Baseline
Brain macro-structure
Whole brain T1-weighted structural MRI will be acquired.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Brain macro-structure
Whole brain T1-weighted structural MRI will be acquired.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Brain macro-structure
Whole brain T1-weighted structural MRI will be acquired.
Time frame: At 3 months follow-up
Brain micro-structure
Whole-brain T2-weighted images will be obtained.
Time frame: Baseline
Brain micro-structure
Whole-brain T2-weighted images will be obtained.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Brain micro-structure
Whole-brain T2-weighted images will be obtained.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Brain micro-structure
Whole-brain T2-weighted images will be obtained.
Time frame: At 3 months follow-up
Functional brain connectivity
Resting-state functional MRI will be performed to acquire insight into subnetworks relating to sensorimotor control and pain processing.
Time frame: Baseline
Functional brain connectivity
Resting-state functional MRI will be performed to acquire insight into subnetworks relating to sensorimotor control and pain processing.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Functional brain connectivity
Resting-state functional MRI will be performed to acquire insight into subnetworks relating to sensorimotor control and pain processing.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Functional brain connectivity
Resting-state functional MRI will be performed to acquire insight into subnetworks relating to sensorimotor control and pain processing.
Time frame: At 3 months follow-up
Lumbar muscle structure
T1-weighted Dixon MRI will be performed.
Time frame: Baseline
Lumbar muscle structure
T1-weighted Dixon MRI will be performed.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Lumbar muscle structure
T1-weighted Dixon MRI will be performed.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Lumbar muscle structure
T1-weighted Dixon MRI will be performed.
Time frame: At 3 months follow-up
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Lumbar muscle function
T2-weighted mf-MRI will be conducted.
Time frame: Baseline
Lumbar muscle function
T2-weighted mf-MRI will be conducted.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Lumbar muscle function
T2-weighted mf-MRI will be conducted.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Lumbar muscle function
T2-weighted mf-MRI will be conducted.
Time frame: At 3 months follow-up.
Lumbopelvic control
Lumbopelvic control will be examined by means of a clinical thoracolumbar dissociation test which assesses the quality of performance of lumbopelvic motion with limited motion at the thoracolumbar junction.
Time frame: Baseline
Lumbopelvic control
Lumbopelvic control will be examined by means of a clinical thoracolumbar dissociation test which assesses the quality of performance of lumbopelvic motion with limited motion at the thoracolumbar junction.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Lumbopelvic control
Lumbopelvic control will be examined by means of a clinical thoracolumbar dissociation test which assesses the quality of performance of lumbopelvic motion with limited motion at the thoracolumbar junction.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Lumbopelvic control
Lumbopelvic control will be examined by means of a clinical thoracolumbar dissociation test which assesses the quality of performance of lumbopelvic motion with limited motion at the thoracolumbar junction.
Time frame: At 3 months follow-up.
Lumbopelvic proprioception
To evaluate lumbar proprioception, the position-reposition accuracy of the lumbar spine will be determined.
Time frame: Baseline
Lumbopelvic proprioception
To evaluate lumbar proprioception, the position-reposition accuracy of the lumbar spine will be determined.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Lumbopelvic proprioception
To evaluate lumbar proprioception, the position-reposition accuracy of the lumbar spine will be determined.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Lumbopelvic proprioception
To evaluate lumbar proprioception, the position-reposition accuracy of the lumbar spine will be determined.
Time frame: At 3 months follow-up.
Anticipatory postural adjustments
To examine anticipatory postural adjustments (APAs) trunk muscle onset latencies in response to internal-induced perturbations will be measured by means of surface electromyography (EMG). APAs will be measured by inducing internal perturbations in the trunk muscles during a reliable and valid unilateral rapid arm movement task (RAM).
Time frame: Baseline
Anticipatory postural adjustments
To examine anticipatory postural adjustments (APAs) trunk muscle onset latencies in response to internal-induced perturbations will be measured by means of surface electromyography (EMG). APAs will be measured by inducing internal perturbations in the trunk muscles during a reliable and valid unilateral rapid arm movement task (RAM).
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Anticipatory postural adjustments
To examine anticipatory postural adjustments (APAs) trunk muscle onset latencies in response to internal-induced perturbations will be measured by means of surface electromyography (EMG). APAs will be measured by inducing internal perturbations in the trunk muscles during a reliable and valid unilateral rapid arm movement task (RAM).
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Anticipatory postural adjustments
To examine anticipatory postural adjustments (APAs) trunk muscle onset latencies in response to internal-induced perturbations will be measured by means of surface electromyography (EMG). APAs will be measured by inducing internal perturbations in the trunk muscles during a reliable and valid unilateral rapid arm movement task (RAM).
Time frame: At 3 months follow-up
Compensatory postural adjustments
To examine compensatory postural adjustments (CPAs), trunk muscle onset latencies in response to external-induced perturbations will be measured by means of surface electromyography (EMG). CPAs will be measured by using external perturbations of trunk muscles during a quick-force-release test (QFRT).
Time frame: Baseline
Compensatory postural adjustments
To examine compensatory postural adjustments (CPAs), trunk muscle onset latencies in response to external-induced perturbations will be measured by means of surface electromyography (EMG). CPAs will be measured by using external perturbations of trunk muscles during a quick-force-release test (QFRT).
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Compensatory postural adjustments
To examine compensatory postural adjustments (CPAs), trunk muscle onset latencies in response to external-induced perturbations will be measured by means of surface electromyography (EMG). CPAs will be measured by using external perturbations of trunk muscles during a quick-force-release test (QFRT).
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Compensatory postural adjustments
To examine compensatory postural adjustments (CPAs), trunk muscle onset latencies in response to external-induced perturbations will be measured by means of surface electromyography (EMG). CPAs will be measured by using external perturbations of trunk muscles during a quick-force-release test (QFRT).
Time frame: At 3 months follow-up
Nociceptive flexion reflex - threshold
The NFR will be elicited in the dominant leg by transcutaneous electrical stimulation of the sural nerve in its retromalleolar path using a stimulation bar electrode connected to a constant current stimulator. Surface EMG electrodes will be placed on the skin of the muscle belly of the ipsilateral biceps femoris.
Time frame: Baseline
Nociceptive flexion reflex - threshold
The NFR will be elicited in the dominant leg by transcutaneous electrical stimulation of the sural nerve in its retromalleolar path using a stimulation bar electrode connected to a constant current stimulator. Surface EMG electrodes will be placed on the skin of the muscle belly of the ipsilateral biceps femoris.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Nociceptive flexion reflex - threshold
The NFR will be elicited in the dominant leg by transcutaneous electrical stimulation of the sural nerve in its retromalleolar path using a stimulation bar electrode connected to a constant current stimulator. Surface EMG electrodes will be placed on the skin of the muscle belly of the ipsilateral biceps femoris.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Nociceptive flexion reflex - threshold
The NFR will be elicited in the dominant leg by transcutaneous electrical stimulation of the sural nerve in its retromalleolar path using a stimulation bar electrode connected to a constant current stimulator. Surface EMG electrodes will be placed on the skin of the muscle belly of the ipsilateral biceps femoris.
Time frame: At 3 months follow-up
Nociceptive flexion reflex - temporal summation
Five 1ms rectangular wave pulse train will be administered 3 times at a frequency of 2 Hz at a constant stimulation intensity. This procedure will be repeated 5 times.
Time frame: Baseline
Nociceptive flexion reflex - temporal summation
Five 1ms rectangular wave pulse train will be administered 3 times at a frequency of 2 Hz at a constant stimulation intensity. This procedure will be repeated 5 times.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Nociceptive flexion reflex - temporal summation
Five 1ms rectangular wave pulse train will be administered 3 times at a frequency of 2 Hz at a constant stimulation intensity. This procedure will be repeated 5 times.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Nociceptive flexion reflex - temporal summation
Five 1ms rectangular wave pulse train will be administered 3 times at a frequency of 2 Hz at a constant stimulation intensity. This procedure will be repeated 5 times.
Time frame: At 3 months follow-up
Conditioned pain modulation
The conditioning stimulus will comprise of immersion of the non-dominant hand until the proximal wrist crease in a hot circulating water bath of 45.5°C during 6 minutes. The test stimulus will comprise of pressure pain threshold (PPT) assessments (as described above) during and after completion of the conditioning stimulus. Before, after 2 min of immersion and 2 minutes after completion of immersion, the test stimulus will be repeated twice at each test location at the dominant body side.
Time frame: Baseline
Conditioned pain modulation
The conditioning stimulus will comprise of immersion of the non-dominant hand until the proximal wrist crease in a hot circulating water bath of 45.5°C during 6 minutes. The test stimulus will comprise of pressure pain threshold (PPT) assessments (as described above) during and after completion of the conditioning stimulus. Before, after 2 min of immersion and 2 minutes after completion of immersion, the test stimulus will be repeated twice at each test location at the dominant body side.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Conditioned pain modulation
The conditioning stimulus will comprise of immersion of the non-dominant hand until the proximal wrist crease in a hot circulating water bath of 45.5°C during 6 minutes. The test stimulus will comprise of pressure pain threshold (PPT) assessments (as described above) during and after completion of the conditioning stimulus. Before, after 2 min of immersion and 2 minutes after completion of immersion, the test stimulus will be repeated twice at each test location at the dominant body side.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Conditioned pain modulation
The conditioning stimulus will comprise of immersion of the non-dominant hand until the proximal wrist crease in a hot circulating water bath of 45.5°C during 6 minutes. The test stimulus will comprise of pressure pain threshold (PPT) assessments (as described above) during and after completion of the conditioning stimulus. Before, after 2 min of immersion and 2 minutes after completion of immersion, the test stimulus will be repeated twice at each test location at the dominant body side.
Time frame: At 3 months follow-up
Anxiety and depression
Hospital Anxiety and depression scale (HADS)
Time frame: Baseline
Anxiety and depression
Hospital Anxiety and depression scale (HADS)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Anxiety and depression
Hospital Anxiety and depression scale (HADS)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Anxiety and depression
Hospital Anxiety and depression scale (HADS)
Time frame: At 3 months follow-up
Physical activity
International physical activity questionnaire - long form (IPAQ-LF)
Time frame: Baseline
Physical activity
International physical activity questionnaire - long form (IPAQ-LF)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Physical activity
International physical activity questionnaire - long form (IPAQ-LF)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Physical activity
International physical activity questionnaire - long form (IPAQ-LF)
Time frame: At 3 months follow-up.
Pain coping
Pain coping inventory (PCI), Pain Catastrophizing Scale (PCS)
Time frame: Baseline
Pain coping
Pain coping inventory (PCI), Pain Catastrophizing Scale (PCS)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Pain coping
Pain coping inventory (PCI), Pain Catastrophizing Scale (PCS)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Pain coping
Pain coping inventory (PCI), Pain Catastrophizing Scale (PCS)
Time frame: At 3 months follow-up
Pain catastrophizing
Pain Catastrophizing Scale (PCS)
Time frame: Baseline
Pain catastrophizing
Pain Catastrophizing Scale (PCS)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Pain catastrophizing
Pain Catastrophizing Scale (PCS)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Pain catastrophizing
Pain Catastrophizing Scale (PCS)
Time frame: At 3 months follow-up
Pain vigilance and awareness
Pain vigilance and awareness questionnaire (PVAQ)
Time frame: Baseline
Pain vigilance and awareness
Pain vigilance and awareness questionnaire (PVAQ)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Pain vigilance and awareness
Pain vigilance and awareness questionnaire (PVAQ)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Pain vigilance and awareness
Pain vigilance and awareness questionnaire (PVAQ)
Time frame: At 3 months follow-up
Kinesiophobia
Tampa Scale for Kinesiophobia (TSK)
Time frame: Baseline
Kinesiophobia
Tampa Scale for Kinesiophobia (TSK)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Kinesiophobia
Tampa Scale for Kinesiophobia (TSK)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Kinesiophobia
Tampa Scale for Kinesiophobia (TSK)
Time frame: At 3 months follow-up
Health status
Short Form Health Survey-36 items (SF-36)
Time frame: Baseline
Health status
Short Form Health Survey-36 items (SF-36)
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Health status
Short Form Health Survey-36 items (SF-36)
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Health status
Short Form Health Survey-36 items (SF-36)
Time frame: At 3 months follow-up
Low back pain related pain
LBP related pain intensity will be evaluated by using an 11 point NRS
Time frame: Baseline
Low back pain related pain
LBP related pain intensity will be evaluated by using an 11 point NRS
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Low back pain related pain
LBP related pain intensity will be evaluated by using an 11 point NRS
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Low back pain related pain
LBP related pain intensity will be evaluated by using an 11 point NRS
Time frame: At 3 months follow-up
Low back pain related disability
The Roland Morris Disability Questionnaire will be used to evaluate disability.
Time frame: Baseline
Low back pain related disability
The Roland Morris Disability Questionnaire will be used to evaluate disability.
Time frame: After low-load training phase (i.e. after 9th supervised treatment session) assessed at approximately 8 weeks
Low back pain related disability
The Roland Morris Disability Questionnaire will be used to evaluate disability.
Time frame: After high-load training phase (i.e. after 18th supervised treatment session) assessed at approximately 13 weeks
Low back pain related disability
The Roland Morris Disability Questionnaire will be used to evaluate disability.
Time frame: At 3 months follow-up
Low back pain recurrence
Self-report via telephone interview: (1) the number of episode(s), (2) the duration of the LBP episode(s), (3) pain intensity, measured with three NRS for average-, worst- and current pain during the LBP episode(s), (4) location and quality of pain (i.e. sharp, burning, etc. sensation), (5) subjects opinion about what caused the new episode of LBP, (6) degree of impairments in daily life activities due to the LBP, (7) whether participants sought treatment (i.e. physiotherapist, general practitioner, etc.) and (8) strategies to cope with the new LBP episode.
Time frame: At 6 months follow-up
Low back pain recurrence
Self-report via telephone interview: (1) the number of episode(s), (2) the duration of the LBP episode(s), (3) pain intensity, measured with three NRS for average-, worst- and current pain during the LBP episode(s), (4) location and quality of pain (i.e. sharp, burning, etc. sensation), (5) subjects opinion about what caused the new episode of LBP, (6) degree of impairments in daily life activities due to the LBP, (7) whether participants sought treatment (i.e. physiotherapist, general practitioner, etc.) and (8) strategies to cope with the new LBP episode.
Time frame: At 12 months follow-up