Experimental validation of a novel spine model demonstrates the large contribution of passive muscle to the flexion relaxation phenomenon

Axial spondyloarthritis (axSpA) is a chronic rheumatic disease characterized by the presence of inflammatory back pain. In patients with chronic low back pain, the lumbar flexion relaxation phenomenon measured by surface electromyography (sEMG) differs from that in healthy individuals. However, sEMG activity in axSpA patients has not been studied. The purpose of this study was to analyze the flexion relaxation phenomenon in axSpA patients. A study evaluating 39 axSpA patients and 35 healthy controls was conducted. sEMG activity at the erector spinae muscles was measured during lumbar full flexion movements. sEMG activity was compared between axSpA patients and the controls, as well as between active (BASDAI ≥ 4) and non-active (BASDAI < 4) patients. The reliability (using intraclass correlation coefficients (ICC)), criterion validity and discriminant validity using the area Under the curve (AUC) for the inverse flexion/relaxation ratio (1/FRR) were evaluated. Significant differences (p < 0.05) were observed between axSpA patients and the control group in lumbar electric activity, especially during flexion, relaxation, and extension and in FRR and 1/FRR (0.66 ± 0.39 vs. 0.25 ± 0.19, respectively). In addition, significant differences were found between active and non-active but also between non-active and healthy subjects. The sEMG showed good reliability (ICC > 0.8 for 1/FRR) and criterion validity. ROC analysis showed good discriminant validity for axSpA patients (AUC = 0.835) vs. the control group using 1/FRR. An abnormal flexion/relaxation phenomenon exists in axSpA patients compared with controls. sEMG could be an additional objective tool in the evaluation of patient function and disease activity status.

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Quantification of the Lumbar Flexion-Relaxation Phenomenon: Comparing Outcomes of Lumbar Erector Spinae and Superficial Lumbar Multifidus in Standing Full Trunk Flexion and Slumped Sitting Postures

Journal of Manipulative and Physiological Therapeutics ◽

10.1016/j.jmpt.2014.07.003 ◽

2014 ◽

Vol 37 (7) ◽

pp. 494-501 ◽

Cited By ~ 12

Author(s):

Alison Schinkel-Ivy ◽

Brian C. Nairn ◽

Janessa D.M. Drake

Keyword(s):

Erector Spinae ◽

Relaxation Phenomenon ◽

Trunk Flexion ◽

Lumbar Multifidus ◽

Lumbar Flexion ◽

Flexion Relaxation Phenomenon ◽

Flexion Relaxation

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Electromyography Pattern Likelihood Analysis for Flexion-Relaxation Phenomenon Evaluation

Electronics ◽

10.3390/electronics9122046 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2046

Author(s):

Michele Paoletti ◽

Alberto Belli ◽

Lorenzo Palma ◽

Paola Pierleoni

Keyword(s):

Back Pain ◽

Gold Standard ◽

Relaxation Phenomenon ◽

Measurement Unit ◽

Myoelectric Activity ◽

Back Muscles ◽

Likelihood Analysis ◽

Validity Range ◽

Flexion Relaxation Phenomenon ◽

Flexion Relaxation

The myoelectric activity of the back muscles can be studied to evaluate the flexion-relaxation phenomenon and find differences between electromyography patterns on different subjects. In this paper, we propose an algorithm able to provide a myoelectric silence evaluation based on the data acquired from a wireless body sensor network consisting of surface electromyography sensors in association with a wearable inertial measurement unit. From the study group was chosen a gold standard subject, a healthy control with the best regular patterns, as a reference to find a first validity range. Through the subsequent iterations, the range was modified to include the other healthy subjects who showed muscle relaxation according to the previous ranges. Through this likelihood analysis, we want to compare patterns on different channels, identified by the electromyography root mean squared values, to study and find with iterations a validity range for the myoelectric activity silence identification and classification. The proposed algorithm was tested by processing the data collected in an acquisition campaign conducted to evaluate the flexion-relaxation phenomenon on the back muscles of subjects with and without lower back pain. The results show that the submitted method is significant for the clinical assessment of electromyography activity patterns to evaluate which are the subjects that have patterns near or far from the gold standard. This analysis is useful both for prevention and for assessing the progress of subjects with low back pain undergoing physiotherapy.

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Comparison of Flexion Relaxation Phenomenon Between Female Yogis and Matched Non- Athlete Group

10.21203/rs.3.rs-898331/v1 ◽

2021 ◽

Author(s):

Marzyeh Ramezani ◽

Amin Kordi Yoosefinejad ◽

Alireza Motealleh ◽

Mohsen Ghofrani-Jahromi

Keyword(s):

Erector Spinae ◽

Relaxation Phenomenon ◽

Control Group ◽

Trunk Flexion ◽

Lumbar Flexion ◽

Trunk Inclination ◽

Forward Bending ◽

Flexion Relaxation Phenomenon ◽

Flexion Relaxation ◽

Yoga Practitioners

Abstract Background: Trunk flexion is a common exercise during daily activities. Flexion relaxation phenomenon (FRP) occurs during forward bending in which there is a sudden silence of erector spinae (ES) muscles. The pattern of forward bending differs in yoga practitioners. This learned pattern probably predisposes yogis to injuries.The hypothesis of this study was that FRP differs in yogis in comparison to non-yogis individuals.Methods: This observational cross-sectional study was performed on 60 women assigned into yogis and non-athlete groups. Each participant was asked to bend forward and then return to the initial position. ES activity was recorded at L3 level, 4 cm from mid line during the trial. Trunk inclination and lumbar flexion angles were calculated at FRP onset and cessation moments. Results: The FRP phenomenon occurred in 80% of yoga practitioners in comparison to 96.7% in the control group. Trunk inclination angle was significantly greater at FRP initiation in yogis compared to control group. Lumbar flexion angle was not different between the groups. Conclusions: It is concluded that the altered pattern of forward bending observed in yogis may change patterns of ES muscles activity if it becomes part of a person's daily lifestyle which might predispose these muscles to fatigue and subsequent injuries.

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O 086 - Relation between the flexion-relaxation phenomenon and back extensor endurance in non-specific chronic low back pain patients

Gait & Posture ◽

10.1016/j.gaitpost.2018.06.105 ◽

2018 ◽

Vol 65 ◽

pp. 176-177 ◽

Cited By ~ 2

Author(s):

K. Rose-Dulcina ◽

S. Genevay ◽

D.E. Dominguez ◽

S. Armand ◽

N. Vuillerme

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Chronic Low Back Pain ◽

Relaxation Phenomenon ◽

Low Back ◽

Flexion Relaxation Phenomenon ◽

Flexion Relaxation ◽

Pain Patients ◽

Back Extensor

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A Wireless Body Sensor Network for Clinical Assessment of the Flexion-Relaxation Phenomenon

Electronics ◽

10.3390/electronics9061044 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1044 ◽

Cited By ~ 2

Author(s):

Michele Paoletti ◽

Alberto Belli ◽

Lorenzo Palma ◽

Massimo Vallasciani ◽

Paola Pierleoni

Keyword(s):

Sensor Network ◽

Clinical Assessment ◽

Activity Patterns ◽

Relaxation Test ◽

Relaxation Phenomenon ◽

Myoelectric Activity ◽

Back Muscles ◽

Body Sensor Network ◽

Flexion Relaxation Phenomenon ◽

Flexion Relaxation

An accurate clinical assessment of the flexion-relaxation phenomenon on back muscles requires objective tools for the analysis of surface electromyography signals correlated with the real movement performed by the subject during the flexion-relaxation test. This paper deepens the evaluation of the flexion-relaxation phenomenon using a wireless body sensor network consisting of sEMG sensors in association with a wearable device that integrates accelerometer, gyroscope, and magnetometer. The raw data collected from the sensors during the flexion relaxation test are processed by an algorithm able to identify the phases of which the test is composed, provide an evaluation of the myoelectric activity and automatically detect the phenomenon presence/absence. The developed algorithm was used to process the data collected in an acquisition campaign conducted to evaluate the flexion-relaxation phenomenon on back muscles of subjects with and without Low Back Pain. The results have shown that the proposed method is significant for myoelectric silence detection and for clinical assessment of electromyography activity patterns.

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