Multifidus EMG and Tension–Relaxation Recovery After Prolonged Static Lumbar Flexion

Jackson, Mclean; Solomonow, Moshe; Zhou, Bing; Baratta, R.; Harris, Mitchel B.

doi:10.1097/00007632-200104010-00003

Cited by 61 publications

(56 citation statements)

References 37 publications

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“…This suggests that paraspinal reflexes may play a significant role in the control of trunk muscle stiffness and associated spinal stability. In animal models brief periods of hyperexcitable reflexes after flexion-relaxation was followed by prolonged periods of reflex depression that may limit spinal stability (Claude et al, 2003;Jackson et al, 2001;Solomonow et al, 1999). Further research is necessary in human subjects to determine whether reflex inhibition is observed following the period of hyper-excitability associated with prolonged flexion relaxation.…”

Section: Discussionmentioning

confidence: 99%

“…Active muscular recruitment and reflexes play a major role in both spinal and ligamentous load as well as spinal stability (GardnerMorse and Stokes, 1998;Granata and Marras, 1995). However, neuromuscular activity may be disturbed by periods of static or cyclic strain in the spinal ligaments and discs (Jackson et al, 2001;Solomonow et al, 1999). A change in reflex response associated with flexed working postures may contribute to limitations in stabilizing control and risk of injury (Solomonow et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, a perturbation force applied to the trunk causes transient tissue strain and excitation of large mechanoreceptors (Golgi, Pacinin, Ruffini fibers) in the spinal ligaments as well as type Ia and type II afferent muscle spindle sensors to initiate reflexive action of the paraspinal muscles (Simon, 1994). Biomechanical laxity of the spine from prolonged trunk flexion may influence neurosensor strain and reflex in response to force perturbations (Jackson et al, 2001). Therefore, changes in reflex response following prolonged strain of the spinal ligaments may be related in part to ligament laxity .…”

Section: Introductionmentioning

confidence: 99%

“…In surgical preparations a mechanical strain was applied to feline supraspinal ligaments and the electromyographic response was observed in adjacent paraspinal muscles (Solomonow et al, 1998). Following repeated ligament strain a brief period of reflex hyper-excitability was observed (Jackson et al, 2001). However, this period of hyperexcitability was short lived.…”

Section: Introductionmentioning

confidence: 99%

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Effects of static flexion–relaxation on paraspinal reflex behavior

Granata

Rogers

Moorhouse

2005

Clinical Biomechanics

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Background.-Static trunk flexion working postures and disturbed trunk muscle reflexes are related to increased risk of low-back pain. Animal studies conclude that these factors may be related; passive tissue strain in spinal ligaments causes subsequent short-term changes in reflex. Although studies have documented changes in the myoelectric onset angle of flexion-relaxation following prolonged static flexion and cyclic flexion we could find no published evidence related to the human reflex response of the trunk extensor muscles following a period of static flexion-relaxation loading.Methods.-Eighteen subjects maintained static lumbar flexion for 15 min. Paraspinal muscle reflexes were elicited both before and after the flexion-relaxation protocol using pseudorandom stochastic force disturbances while recording EMG. Reflex gain was computed from the peak value of the impulse response function relating input force perturbation to EMG response using timedomain deconvolution analyses.Findings.-Reflexes showed a trend toward increased gain after the period of flexion-relaxation (P < 0.055) and were increased with trunk extension exertion (P < 0.021). Significant gender differences in reflex gain were observed (P < 0.01).Interpretations.-Occupational activities requiring extended periods of trunk flexion contribute to changes in reflex behavior of the paraspinal muscles. Results suggest potential mechanisms by which flexed posture work may contribute to low-back pain. Significant gender differences indicate risk analyses should consider personal factors when considering neuromuscular behavior.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of static flexion–relaxation on paraspinal reflex behavior

Granata

Rogers

Moorhouse

2005

Clinical Biomechanics

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“…Inhibition of the multifidus muscle has been shown to occur during static postures, especially into trunk flexion [2]. Prolonged flexion for up to 20 minutes was enough to shut down the EMG activity of the lumbar multifidus for up to 7 hours [3].…”

Section: Introductionmentioning

confidence: 99%

Muscle Inhibition During Cycling in a Patient with Chronic Low Back Pain: Effect of Brief Electrical Stimulation

Bechtel¹,

Benjamin²,

Liu³

2017

J Spine

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Background and purpose: This case study reports patterns of muscle inhibition and techniques for therapeutic intervention in a well-trained cyclist with chronic low back pain (CLBP) following a discectomy at L5-S1. It has been shown that repeated or prolonged flexion can lead to inhibition of the spine stabilizing muscles. Competitive cyclists exert high effort in a flexed posture for prolonged periods. Segmental muscle inhibition could lead to LBP and segmental instability in this population. The purpose of our case study was 1) to determine if a competitive cyclist with CLBP would demonstrate muscle inhibition at the symptomatic level and 2) to determine if a therapeutic intervention (electrical muscle stimulation) applied to the symptomatic level for a short period, could affect function.

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Neuromuscular dysfunction elicited by cyclic lumbar flexion

et al. 2003

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An attempt was made to develop an in vivo model that could explain the neurophysiological and biomechanical processes active in the development of the idiopathic low back disorder common in workers who perform repetitive lifting tasks in industry. Passive cyclic flexion of the feline lumbar spine at 0.1 HZ for 20 min resulted in creep of the supraspinous ligament and other lumbar viscoelastic tissues as well as spasms superimposed on a decreasing electromyogram (EMG) elicited reflexly from the multifidus muscles. Rest for 7 h did not allow full recovery of the viscoelastic creep; the multifidus EMG gradually increased with initial and delayed hyperexcitability. Increasing the peak load of the cyclic flexion resulted in larger creep in the passive tissues and required a longer time for recovery of reflex EMG activity and longer delayed hyperexcitability, but development of spasms and hyperexcitability was unaffected. It is conceivable that damage to the viscoelastic tissues elicits an inflammatory process that in turn triggers a transient neuromuscular disorder. The present findings provide a biomechanical and neurophysiological explanation for a common idiopathic low back disorder as well as for the development of a cumulative trauma disorder often seen in workers engaged in repetitive lumbar flexion.

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Multifidus EMG and Tension–Relaxation Recovery After Prolonged Static Lumbar Flexion

Abstract: Static flexion of the lumbar spine is an extremely imposing function on its viscoelastic tissues, resulting in spasms and requiring long periods of rest before normal functions are re-established.

Cited by 61 publications

References 37 publications

Effects of static flexion–relaxation on paraspinal reflex behavior

Effects of static flexion–relaxation on paraspinal reflex behavior

Muscle Inhibition During Cycling in a Patient with Chronic Low Back Pain: Effect of Brief Electrical Stimulation

Neuromuscular dysfunction elicited by cyclic lumbar flexion

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