The influence of fatigue and chronic low back pain on muscle recruitment patterns following an unexpected external perturbation
Authors: Júlia Jubany Güell
Keywords: Trigger Points. Myofascial Pain Syndromes. Acupressure. Ultrasonic Therapy
Abstract : Chronic low back pain (CLBP) has been associated with altered trunk muscle responses as well as increased muscle fatigability. CLBP patients and fatigued healthy subjects could experience similar neuromuscular strategies to attempt to protect the spine. The current study examined muscle activation differences between healthy and CLBP subjects following a perturbation. In addition, the possible role of muscle fatigue was evaluated by investigating the healthy control subjects in a non-fatigued and a fatigued condition. Both experiments were combined to evaluate possible similar strategies between CLBP and fatigued samples.
07-05-2018
Júlia Jubany Güell
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| Citation: Júlia Jubany Güell. The influence of fatigue and chronic low back pain on muscle recruitment patterns following an unexpected external perturbation. https://doi.org/10.24175/sbd.2018.000073 |
| Received: May 07, 2018 Accepted: May 07, 2018 Published: May 07, 2018 |
| Copyright: © 2018 Júlia Jubany Güell. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY-NC), which allows, distribution, reproduction in any medium, provided the original author and source are credited and non-commercial use. |
| Funding: I certify that no funding has been received for the conduct of this study and/or preparation of this manuscript. |
| Conflicts of Interest: I have no conflicts of interest to declare |
La influència de la fatiga i el dolor crònic lumbar en els patrons de reclutament posteriors a una pertorbació externa inesperada
Júlia Jubany 1,3 Lieven Danneels2 and Rosa Angulo-Barroso1.
Facultat de Ciències de la Salut de Manresa. Universitat de Vic. Universitat Central de Catalunya. 2Ghent University. 3INEFC- Institut Nacional d'Educació Física de Catalunya
Key words: Trigger Points. Myofascial Pain Syndromes. Acupressure. Ultrasonic Therapy.
Palabras clave: Puntos gatillo. Síndromes de dolor miofascial. Acupresión. Terapia de ultrasonidos.
| Background Chronic low back pain (CLBP) has been associated with altered trunk muscle responses as well as increased muscle fatigability. CLBP patients and fatigued healthy subjects could experience similar neuromuscular strategies to attempt to protect the spine. The current study examined muscle activation differences between healthy and CLBP subjects following a perturbation. In addition, the possible role of muscle fatigue was evaluated by investigating the healthy control subjects in a non-fatigued and a fatigued condition. Both experiments were combined to evaluate possible similar strategies between CLBP and fatigued samples. Methods Cross-sectional study where 24 CLBP subjects and 26 healthy subjects were evaluated. Both groups (CLBP vs. healthy) and both conditions (non-fatigued and a fatigued condition) were evaluated while a weight was suddenly dropped on a held tray. Erector spinae, multifidus, obliques and biceps brachii were recorded using surface electromyography. Variables describing the bursts timing and variables describing the amount of muscle activity (number of bursts and amplitude increase) post impact were studied (Figure 1). The analysis between groups and conditions was carried out using ANOVAs with repeated measurements for the muscle factor. Results CLBP subjects reacted similarly to healthy subjects regarding muscle activity post impact. However, the CLBP group showed temporal characteristics of muscle activity that were in between the fatigued and non-fatigued healthy group (Figure 2). Clear differences in muscle activity were displayed for healthy subjects (Table 1 and Figure 3) Fatigued healthy subjects presented more reduced activity after impact (upper limb and trunk muscles) than non-fatigued healthy subjects and different temporal characteristic in the same way than CLBP patients. This same temporal characteristic with CLBP and healthy fatigued people was a delay of the first burst of muscle activity after impact. Conclusion Though similar muscle pattern existed between CLBP and healthy people, CLBP temporal characteristics of muscle activity showed a pattern in between healthy people and fatigued healthy people. While the temporal muscle pattern dysfunction used by CLBP subjects could be related to maladaptive patterns, temporal and muscle activity characteristics used by healthy fatigued people may lead to back injuries. Authors suggest that these muscle patterns present in CLBP and healthy fatigued subjects and especially in sudden perturbations could imply a vulnerability and may play a role in CLBP dysfunction or may lead to back injuries in fatigued people. Annex: |
Table 1. Comparison between non-fatigued healthy subjects and fatigued healthy subjects.
| Principal effect | gl | F | Sig (p) | pŋ2 | Power | Post hoc/Simple factor | |||||||||
| Start 1st Burst | Condition | 24(1) | 4.739 | 0.040 | 0.165 | 0.552 | With-F > Non-F | ||||||||
| Muscle | 9.279 | <0.001 | 0.279 | 0.996 | BB IO | ||||||||||
| Interaction | 2.234 | 0.093 | 0.085 | 0.540 | |||||||||||
| Group mean difference (95% CI)= 14 % (-27, 1) for start 1st Burst | |||||||||||||||
| Start 2nd Burst | Condition | 9 (1) | 0.693 | 0.427 | 0.071 | 0.116 | |||||||||
| Muscle | 3.228 | 0.057 | 0.264 | 0.571 | |||||||||||
| Interaction | 0.623 | 0.568 | 0.065 | 0.146 | |||||||||||
| Group mean difference (95% CI)= 10% (-38, 18) for start 2nd Burst | |||||||||||||||
| Duration 1st Burst | Condition | 24(1) | 15.726 | 0.001 | 0.396 | 0.967 | With-F < Non-F | ||||||||
| Muscle | 42.055 | <0.001 | 0.637 | 1.000 | BB>EO>SE>RM,LM; IO>SE>RM,LM | ||||||||||
| Interaction | 8.794 | 0.001 | 0.268 | 0.963 | BB= With-F < Non-F | ||||||||||
| Group mean difference (95% CI)= 26% (-12, 39) for duration 1st Burst | |||||||||||||||
| Duration 2nd Burst | Condition | 9(1) | 1.214 | 0.299 | 0.119 | 0.167 | |||||||||
| Muscle | 3.023 | 0.098 | 0.251 | 0.413 | |||||||||||
| Interaction | 1.570 | 0.242 | 0.149 | 0.240 | |||||||||||
| Group mean difference (95% CI)= 8% (-8, 24) for duration 2nd Burst | |||||||||||||||
| Num Bursts post impact | Condition | 24(1) | 7.679 | 0.011 | 0.242 | 0.758 | With-F < Non-F | ||||||||
| Muscle | 1.574 | 0.198 | 0.062 | 0.422 | |||||||||||
| Interaction | 2.509 | 0.053 | 0.095 | 0.661 | |||||||||||
| Group mean difference (95% CI)= 0.26% (-0.06, 0.45) for num Bursts post impact | |||||||||||||||
| Post/Pre Ratio | Condition | 24(1) | 28.323 | 0.000 | 0.541 | 0.999 | With-F < Non-F | ||||||||
| Muscle | 20.182 | 0.000 | 0.457 | 1.000 | BB,IO>EO>LM; BB,IO>SE>RM,LM | ||||||||||
| Interaction | 13.798 | 0.000 | 0.365 | 0.992 | SE= With-F < Non-F | ||||||||||
| BB= With-F < Non-F | |||||||||||||||
| Group mean difference (95% CI)= 0.61% (-0.37, 0.85) for start post/Pre Ratio | |||||||||||||||
| Co-co post impact | Condition | 24(1) | 4.625 | 0.042 | 0.162 | 0.542 | With-F < Non-F | ||||||||
| Muscle | 33.856 | <0.001 | 0.585 | 1.000 | SE&EO,SE&IO | ||||||||||
| Interaction | 0.399 | 0.577 | 0.016 | 0.098 | |||||||||||
| Group mean difference (95% CI)= 19.20% (-0.77, 37.62) for co-co post impact | |||||||||||||||
Significant ANOVA results corresponding to the comparisons between healthy subjects without fatigue and healthy subjects with fatigue (group factor) and between muscles (muscle factor) for variables describing the timing and variables describing the amount of muscle activity post impact. Num bursts post impact: number of bursts following the impact; Post/Pre Ratio: ratio of root mean square of the post impact EMG signal amplitude and pre impact EMG signal amplitude; Co-co post impact: co-contraction levels after the impact; BB: biceps brachii; SE: thoracic spinal erector; RM: right multifidus; LM: left multifidus; EO: external oblique; IO: internal oblique.
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Figure 1. Temporal representation of the average value of the bursts of each muscle (biceps brachii (BB), thoracic spinal erector (SE), right multifidus (RM), left multifidus (LM), external oblique (EO), internal oblique (IO)) for both groups and for the condition of fatigue. A. Group without lumbar pathology (H); B. Group with nonspecific chronic low back pain (CLBP); C. Condition of fatigue (With-F). The coloured bars represent, for different muscles, the moment when the first and second bursts after impact starts and their duration. The striped areas represent the parts of the bursts belonging to two different bursts (overlapping).
Figure 2. Mean and standard deviation (error bars) of each muscle (biceps brachii (BB), thoracic spinal erector (SE), right multifidus (RM), left multifidus (LM), external oblique (EO), internal oblique (IO)) of the variable of first burst post impact between healthy subjects, those with chronic low back pain and between healthy subjects with fatigue.
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Figure 3. Mean and standard deviation (error bars) of each muscle (biceps brachii (BB), thoracic spinal erector (SE), right multifidus (RM), left multifidus (LM), external oblique (EO), internal oblique (IO)) of variables describing the timing and variables describing the amount of muscle activity post impact between healthy subjects and those with chronic low back pain and between healthy subjects without fatigue and healthy subjects with fatigue.
