Effects of pregnancy on lumbar motion patterns and muscle responses.
Electromyography
Erector spinae
Flexion relaxation phenomenon
Low back pain
Lumbar region
Pregnancy
Journal
The spine journal : official journal of the North American Spine Society
ISSN: 1878-1632
Titre abrégé: Spine J
Pays: United States
ID NLM: 101130732
Informations de publication
Date de publication:
02 2019
02 2019
Historique:
received:
03
05
2018
revised:
10
08
2018
accepted:
15
08
2018
pubmed:
26
8
2018
medline:
18
12
2019
entrez:
26
8
2018
Statut:
ppublish
Résumé
The kinematics of the lumbar region and the activation patterns of the erector spinae muscle have been associated with the genesis of low back pain, which is one of the most common complications associated with pregnancy. Despite the high prevalence of pregnancy-related low back pain, the biomechanical adaptations of the lumbar region during pregnancy remain unknown. This study analyzes lumbar spine motion and the activation pattern of the lumbar erector spinae muscle in healthy pregnant women. A case-control study. The study involved 34 nulliparous women (control group) and 34 pregnant women in the third trimester (week 36 ± 1). We recorded the parameters of angular displacement of the lumbar spine in the sagittal plane during trunk flexion-extension, and the EMG activity of the erector spinae muscles during flexion, extension, eccentric and concentric contractions, and the myolectrical silence. The participants performed several series of trunk flexion-extension movements, which were repeated 2 months postpartum. The position of the lumbar spine was recorded using an electromagnetic motion capture system. EMG activity was recorded by a surface EMG system and expressed as a percentage of a submaximal reference contraction. Antepartum measurements showed a decrease (relative to control and postpartum measurements) in lumbar maximum flexion (52.5 ± 10.5° vs 57.3 ± 7.7° and 58.7 ± 8.6°; p < .01), the percentage of lumbar flexion during forward bending (56.4 ± 5.6% vs 59.4 ± 6.8% and 59.7 ± 5.6%; p < .01), and the time keeping maximum levels of lumbar flexion (35.7 ± 6.7% vs 43.8 ± 5.3% and 50.1 ± 3.7%; p < .01). Higher levels of erector spinae activation were observed in pregnant women during forward bending (10.1 ± 4.8% vs 6.3 ± 2.4% and 6.6 ± 2.7%; p < .01) and eccentric contraction (12.1 ± 5.2% vs 9.4 ± 3.1% and 9.1 ± 2.9%; p < .01), as well as a shortened erector spinae myoelectric silence during flexion. Pregnant women show adaptations in their patterns of lumbar motion and erector spinae activity during trunk flexion-extension. These changes could be associated with the genesis of pregnancy-related low back pain, by means of biomechanical protection mechanisms against the increase on abdominal mass and ligamentous laxity.
Sections du résumé
BACKGROUND CONTEXT
The kinematics of the lumbar region and the activation patterns of the erector spinae muscle have been associated with the genesis of low back pain, which is one of the most common complications associated with pregnancy. Despite the high prevalence of pregnancy-related low back pain, the biomechanical adaptations of the lumbar region during pregnancy remain unknown.
PURPOSE
This study analyzes lumbar spine motion and the activation pattern of the lumbar erector spinae muscle in healthy pregnant women.
STUDY DESIGN
A case-control study.
PATIENT SAMPLE
The study involved 34 nulliparous women (control group) and 34 pregnant women in the third trimester (week 36 ± 1).
OUTCOME MEASURES
We recorded the parameters of angular displacement of the lumbar spine in the sagittal plane during trunk flexion-extension, and the EMG activity of the erector spinae muscles during flexion, extension, eccentric and concentric contractions, and the myolectrical silence.
METHODS
The participants performed several series of trunk flexion-extension movements, which were repeated 2 months postpartum. The position of the lumbar spine was recorded using an electromagnetic motion capture system. EMG activity was recorded by a surface EMG system and expressed as a percentage of a submaximal reference contraction.
RESULTS
Antepartum measurements showed a decrease (relative to control and postpartum measurements) in lumbar maximum flexion (52.5 ± 10.5° vs 57.3 ± 7.7° and 58.7 ± 8.6°; p < .01), the percentage of lumbar flexion during forward bending (56.4 ± 5.6% vs 59.4 ± 6.8% and 59.7 ± 5.6%; p < .01), and the time keeping maximum levels of lumbar flexion (35.7 ± 6.7% vs 43.8 ± 5.3% and 50.1 ± 3.7%; p < .01). Higher levels of erector spinae activation were observed in pregnant women during forward bending (10.1 ± 4.8% vs 6.3 ± 2.4% and 6.6 ± 2.7%; p < .01) and eccentric contraction (12.1 ± 5.2% vs 9.4 ± 3.1% and 9.1 ± 2.9%; p < .01), as well as a shortened erector spinae myoelectric silence during flexion.
CONCLUSIONS
Pregnant women show adaptations in their patterns of lumbar motion and erector spinae activity during trunk flexion-extension. These changes could be associated with the genesis of pregnancy-related low back pain, by means of biomechanical protection mechanisms against the increase on abdominal mass and ligamentous laxity.
Identifiants
pubmed: 30144534
pii: S1529-9430(18)31097-0
doi: 10.1016/j.spinee.2018.08.009
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
364-371Informations de copyright
Copyright © 2018. Published by Elsevier Inc.