Repeated spinal flexion modulates the flexion–relaxation phenomenon

Dickey, James P.; McNorton, Sara; Potvin, Jim R.

doi:10.1016/s0268-0033(03)00166-9

Cited by 80 publications

(78 citation statements)

References 37 publications

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“…Therefore, changes in reflex response following prolonged strain of the spinal ligaments may be related in part to ligament laxity . Although studies have documented changes in the myoelectric onset angle of flexion-relaxation following prolonged static flexion and cyclic flexion (Dickey et al, 2003;Solomonow et al, 2003a), we could find no published evidence related to the human reflex response of the trunk extensor muscles following prolonged passive stretch.…”

Section: Introductioncontrasting

confidence: 62%

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: Introductioncontrasting

confidence: 62%

Effects of static flexion–relaxation on paraspinal reflex behavior

Granata

Rogers

Moorhouse

2005

Clinical Biomechanics

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“…These are called absolute because the threshold was 8 defined once and then used throughout the experiment (Table 1). While it is recognized that these 3% and 5% MVC IEMGs, captured in a 20 degree trunk flexion posture, are not an exact match with those that would have been collected in the near full flexion posture, this technique is consistent with those studies employing this % MVC approach (Dickey et al, 2003;McGill and Kippers, 1994;Shin et al, 2009). By contrast, the self-reference threshold values are calculated on a trial-by-trial basis.…”

Section: Computer-based Frp Determinationsupporting

confidence: 72%

“…Previous studies have employed a visual inspection method that is subjective and timeconsuming (Dickey et al, 2003;Descarreaux et al, 2008;Gupta, 2001). A few studies attempted computer-based methods using various smoothing techniques and thresholds (Olson et al, 2004;Shin et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

An algorithm for defining the onset and cessation of the flexion-relaxation phenomenon in the low back musculature

Jin

Ning

Mirka

2012

Journal of Electromyography and Kinesiology

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The flexion-relaxation phenomenon (FRP) in the low back provides insights into the interplay between the active and passive tissues. Establishing a reliable algorithm for defining the lumbar angle at which the muscles deactivate and reactivate was the focus of the current paper. First, the EMG data were processed using six different smoothing techniques (no smoothing, moving average, moving standard deviation, Butterworth low pass filter at 0.5Hz, 5Hz, and 50Hz) herein called the processed EMG (pEMG). The FRP points were then defined using four thresholds (pEMG less than 3% MVC, pEMG less than 5% MVC, pEMG less than 2 times FRP pEMG, and pEMG less than 3 times FRP pEMG). Finally, a duration requirement was tested (no duration requirement, pEMG data must maintain threshold requirement for 50 data points). Each combination of smoothing, threshold, and duration were applied through a computer program to each muscle for all trials and established an EMG-off and EMG-on angle for each muscle.These estimates were compared to the gold standard of expert-identified EMG-off and EMG-on angles and the root mean square error (RMSE) between this gold standard and the predictions of the algorithms served as the dependent variable. The results showed that the most important factor to produce low values of RMSE is to utilize a Butterwort low pass filter of 5Hz or less and, if this is employed, there is no value to a duration requirement. The results also suggest that using the "3 times FRP pEMG" threshold technique may provide further improvements in these predictions.3

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“…This could be due to the minimal neuromuscular activation during passive sessions thereby showing that the muscles were not actively involved in resisting or assisting the passive movement as proposed by Olson. As the load on posterior lumbar tissues is increased the angle of trunk flexion also increases, whether statically or in repetitive cyclic movements (Dickey et al 2003;McGill & Brown1992). The increase in trunk flexion causes the lumbar tissues to become the dominant load bearers (Ning & Mirka, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…Prolonged static (Granta, Slota &Bennett., Shin, Shu,Li, Jiang & Mirka., Solomonow et al 2003) and cyclic (Dickey et al 2003, Olson et al 2004Olson, Li & Solomonow, 2009;Olson 2011) trunk flexion protocols have been used in humans, to observe the response of the neuromuscular system overtime (Olson et al, 2009) Previously, viscoelastic properties of lumbar posterior tissues, in-vivo, have been described (Olson et al, 2009;Toosizadeh, Nussbaum, Bazrgari, and Madigan, 2012) affect stress levels on those tissues (Ning & Nussbaum, 2015). McGill and Brown (1992) imply that prolonged static flexion of the trunk drastically alters the viscoelastic properties of the tissues which may lead to a potential compromise in the stability of the spine.…”

Section: Introductionmentioning

confidence: 99%

Recovery Of Force Output And Electromyography From Trunk Muscles After Cyclic Passive Loading.

Vij¹,

Olson²

2014

Medicine & Science in Sports & Exercise

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Continuous loading of the low back tissues results in modified neuromuscular and kinetic output during trunk extension efforts. It is believed that the viscoelastic behavior of these low back tissues is modified, but the ramifications of these loading schemes needs further study for longer durations. The purpose of this research project was to observe force output and muscle activation pattern changes during trunk extension efforts before and up to 60 minutes after

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Repeated spinal flexion modulates the flexion–relaxation phenomenon

Cited by 80 publications

References 37 publications

Effects of static flexion–relaxation on paraspinal reflex behavior

Effects of static flexion–relaxation on paraspinal reflex behavior

An algorithm for defining the onset and cessation of the flexion-relaxation phenomenon in the low back musculature

Recovery Of Force Output And Electromyography From Trunk Muscles After Cyclic Passive Loading.

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