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The relative timing of trunk muscle activation is retained in response to unanticipated postural-perturbations during acute low back pain.

Boudreau S, Farina D, Kongstad L, Buus D, Redder J, Sverrisdóttir E, Falla D - Exp Brain Res (2011)

Bottom Line: In each condition, participants stood on a moveable platform during which 32 randomized postural perturbations (8 repetitions of 4 perturbation types: 8 cm anterior slides, 8 cm posterior slides, 10° anterior tilts, and 10° posterior tilts) with varying inter-perturbation time intervals were performed over a period of 4-5 min.During the acute LBP condition: (1) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations (P < 0.05); (2) EMG amplitude was reduced bilaterally for all perturbations (P < 0.05); (3) the order of activation and interval between the onset times of the ES and EO were unaltered and (4) ES, but not EO, activity was adjusted to account for the directional differences between the perturbations.This study revealed that re-establishment of posture and balance was a result of the individuals' ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses, although shifted in time and amplitude, retained temporal features in the presence of acute LBP.

View Article: PubMed Central - PubMed

Affiliation: Center for Sensory-Motor Interaction, Department of Health Science and Technology Faculty of Medicine, Aalborg University, Aalborg, Denmark.

ABSTRACT
The purpose of this study was to assess the activation of the erector spinae (ES) and external oblique (EO) in response to unanticipated, bi-directional postural perturbations before and after the induction of acute low back pain (LBP) in healthy individuals. An experimental session consisted of a baseline, control, and an acute LBP condition. For the control and acute LBP condition, isotonic or hypertonic saline (HS), respectively, was injected into the right ES muscle. In each condition, participants stood on a moveable platform during which 32 randomized postural perturbations (8 repetitions of 4 perturbation types: 8 cm anterior slides, 8 cm posterior slides, 10° anterior tilts, and 10° posterior tilts) with varying inter-perturbation time intervals were performed over a period of 4-5 min. Bilateral surface electromyography (EMG) was recorded from the ES and EO in addition to subjective pain records. During the acute LBP condition: (1) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations (P < 0.05); (2) EMG amplitude was reduced bilaterally for all perturbations (P < 0.05); (3) the order of activation and interval between the onset times of the ES and EO were unaltered and (4) ES, but not EO, activity was adjusted to account for the directional differences between the perturbations. This study revealed that re-establishment of posture and balance was a result of the individuals' ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses, although shifted in time and amplitude, retained temporal features in the presence of acute LBP.

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Mean of the left- and right EMG amplitude (a, b) and onset time (c, d) of the erector spinae (ES) and external oblique (EO) during the baseline, control, and low back pain conditions for the anterior and posterior sliding perturbations. *Represents significant post hoc SNK results (P < 0.05)
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Fig4: Mean of the left- and right EMG amplitude (a, b) and onset time (c, d) of the erector spinae (ES) and external oblique (EO) during the baseline, control, and low back pain conditions for the anterior and posterior sliding perturbations. *Represents significant post hoc SNK results (P < 0.05)

Mentions: For the acute experimental pain condition, there was a decrease in EMG amplitude (ANOVA, F = 6.7; P = 0.006) for the ES and EO in comparison with the control (SNK, P = 0.013) and baseline (SNK, P = 0.007) conditions (Fig. 4a). As indicated in Fig. 4b, there was also a delay in EMG onset (ANOVA, F = 4.6; P = 0.024) for the ES and EO in comparison with the control (SNK, P = 0.036) and baseline (SNK, P = 0.020) conditions. There was, however, no difference between the left and right ES or EO across conditions for EMG amplitude (ANOVA, F = 1.7; P = 0.20) or EMG onset (ANOVA, F = 0.3; P = 0.72); data not shown. The EMG onset time for the ES was consistently later than the EO (ANOVA, F = 29.519, P = 0.0004; SNK, P = 0.0005) and the difference between the ES and EO onset times was retained during acute LBP (ANOVA, F = 0.5, P = 0.594).Fig. 4


The relative timing of trunk muscle activation is retained in response to unanticipated postural-perturbations during acute low back pain.

Boudreau S, Farina D, Kongstad L, Buus D, Redder J, Sverrisdóttir E, Falla D - Exp Brain Res (2011)

Mean of the left- and right EMG amplitude (a, b) and onset time (c, d) of the erector spinae (ES) and external oblique (EO) during the baseline, control, and low back pain conditions for the anterior and posterior sliding perturbations. *Represents significant post hoc SNK results (P < 0.05)
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3066398&req=5

Fig4: Mean of the left- and right EMG amplitude (a, b) and onset time (c, d) of the erector spinae (ES) and external oblique (EO) during the baseline, control, and low back pain conditions for the anterior and posterior sliding perturbations. *Represents significant post hoc SNK results (P < 0.05)
Mentions: For the acute experimental pain condition, there was a decrease in EMG amplitude (ANOVA, F = 6.7; P = 0.006) for the ES and EO in comparison with the control (SNK, P = 0.013) and baseline (SNK, P = 0.007) conditions (Fig. 4a). As indicated in Fig. 4b, there was also a delay in EMG onset (ANOVA, F = 4.6; P = 0.024) for the ES and EO in comparison with the control (SNK, P = 0.036) and baseline (SNK, P = 0.020) conditions. There was, however, no difference between the left and right ES or EO across conditions for EMG amplitude (ANOVA, F = 1.7; P = 0.20) or EMG onset (ANOVA, F = 0.3; P = 0.72); data not shown. The EMG onset time for the ES was consistently later than the EO (ANOVA, F = 29.519, P = 0.0004; SNK, P = 0.0005) and the difference between the ES and EO onset times was retained during acute LBP (ANOVA, F = 0.5, P = 0.594).Fig. 4

Bottom Line: In each condition, participants stood on a moveable platform during which 32 randomized postural perturbations (8 repetitions of 4 perturbation types: 8 cm anterior slides, 8 cm posterior slides, 10° anterior tilts, and 10° posterior tilts) with varying inter-perturbation time intervals were performed over a period of 4-5 min.During the acute LBP condition: (1) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations (P < 0.05); (2) EMG amplitude was reduced bilaterally for all perturbations (P < 0.05); (3) the order of activation and interval between the onset times of the ES and EO were unaltered and (4) ES, but not EO, activity was adjusted to account for the directional differences between the perturbations.This study revealed that re-establishment of posture and balance was a result of the individuals' ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses, although shifted in time and amplitude, retained temporal features in the presence of acute LBP.

View Article: PubMed Central - PubMed

Affiliation: Center for Sensory-Motor Interaction, Department of Health Science and Technology Faculty of Medicine, Aalborg University, Aalborg, Denmark.

ABSTRACT
The purpose of this study was to assess the activation of the erector spinae (ES) and external oblique (EO) in response to unanticipated, bi-directional postural perturbations before and after the induction of acute low back pain (LBP) in healthy individuals. An experimental session consisted of a baseline, control, and an acute LBP condition. For the control and acute LBP condition, isotonic or hypertonic saline (HS), respectively, was injected into the right ES muscle. In each condition, participants stood on a moveable platform during which 32 randomized postural perturbations (8 repetitions of 4 perturbation types: 8 cm anterior slides, 8 cm posterior slides, 10° anterior tilts, and 10° posterior tilts) with varying inter-perturbation time intervals were performed over a period of 4-5 min. Bilateral surface electromyography (EMG) was recorded from the ES and EO in addition to subjective pain records. During the acute LBP condition: (1) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations (P < 0.05); (2) EMG amplitude was reduced bilaterally for all perturbations (P < 0.05); (3) the order of activation and interval between the onset times of the ES and EO were unaltered and (4) ES, but not EO, activity was adjusted to account for the directional differences between the perturbations. This study revealed that re-establishment of posture and balance was a result of the individuals' ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses, although shifted in time and amplitude, retained temporal features in the presence of acute LBP.

Show MeSH
Related in: MedlinePlus