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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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Related in: MedlinePlus

Shadings of perceived area of pain associated with the injection of isotonic (a) or hypertonic (b) saline into the right lower back
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Fig3: Shadings of perceived area of pain associated with the injection of isotonic (a) or hypertonic (b) saline into the right lower back

Mentions: The mean pain intensity following injection of hypertonic saline was 3.9 ± 0.5. Peak pain intensity occurred at 80 s following injection of hypertonic saline and the pain intensity was greater than zero, for all participants, throughout the duration of the 32 perturbations, see Fig. 2. Participants described the quality of pain following the isotonic injection (0.50 ± 0.46) as boring, scalding, tender, annoying and tight. In contrast, participants described the quality of pain following the hypertonic injection as drilling, sharp, pressing, scalding, taut, miserable and tight, with scalding being the most common reported pain quality descriptor. The subjective shadings of pain area on the body chart, see Fig. 3, revealed that all participants perceived the pain following the hypertonic saline injection as being restricted to the side of injection (right side).Fig. 2


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)

Shadings of perceived area of pain associated with the injection of isotonic (a) or hypertonic (b) saline into the right lower back
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3066398&req=5

Fig3: Shadings of perceived area of pain associated with the injection of isotonic (a) or hypertonic (b) saline into the right lower back
Mentions: The mean pain intensity following injection of hypertonic saline was 3.9 ± 0.5. Peak pain intensity occurred at 80 s following injection of hypertonic saline and the pain intensity was greater than zero, for all participants, throughout the duration of the 32 perturbations, see Fig. 2. Participants described the quality of pain following the isotonic injection (0.50 ± 0.46) as boring, scalding, tender, annoying and tight. In contrast, participants described the quality of pain following the hypertonic injection as drilling, sharp, pressing, scalding, taut, miserable and tight, with scalding being the most common reported pain quality descriptor. The subjective shadings of pain area on the body chart, see Fig. 3, revealed that all participants perceived the pain following the hypertonic saline injection as being restricted to the side of injection (right side).Fig. 2

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