Evaluation of the Flexion Relaxation Phenomenon of the Trunk Muscles in Sitting

O’Sullivan, Peter; Dankaerts, Wim; Burnett, Angus; Chen, Dvir; Booth, Randy; Carlsen, Charlotte Green; Schultz, A

doi:10.1097/01.brs.0000228845.27561.e0

Cited by 90 publications

(79 citation statements)

References 34 publications

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“…Previous literature showed that healthy subjects tend to slump into lumbar flexion during prolonged sitting and also demonstrate repositioning errors in sitting and standing postures [41,45,68,69]. Maffey-Ward et al [68] found a between-day error of 2.6°during sitting while Swinkels and Dolan [41] showed between-day errors of 5.27 ± 3.47°d uring lumbar spine sagittal movement.…”

Section: Discussionmentioning

confidence: 99%

Preliminary study: reliability of the spinal wheel. A novel device to measure spinal postures applied to sitting and standing

et al. 2009

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Postural re-education is an integral part of physiotherapy management in patients with back pain. Although the link between posture and back pain is largely unknown, postural re-education is performed on the premise of optimizing spinal alignment to minimize stresses on the passive structures of the spine, to facilitate optimal muscular support and thus to prevent possible damage and further pain. A reliable and clinically meaningful measurement of spinal postures to monitor such interventions remains challenging. This study evaluated within-day (intra-tester, inter-tester) and between-day (test-retest) reliability of a novel spinal wheel device measuring thoracic and lumbar postures during sitting and standing. 17 healthy volunteers (age 39.5 ± 5.4, BMI 25 ± 9.2; 9 males) were measured three times, by three testers, on two separate occasions (1 week apart). The angular change between C7 and T12 and between T12 and S1 provided thoracic and lumbar curvatures, respectively. Intra-class correlation coefficient (ICC) with 95% confidence intervals and typical error were calculated. Excellent reliability was demonstrated with intra-tester ICCs between 0.947 and 0.980 and typical error between 1.7°and 3.7°and intertester ICCs between 0.949 and 0.986 and typical error between 2.0°and 4.7°. Test-retest reliability was high with ICCs 0.719-0.908 and typical error between 4.0°and 7.4°. In conclusion, the spinal wheel demonstrated excellent within-day and high between-day reliability. The device may be used in conjunction with 2D camcorder to provide clinically useful visual evaluation of postures for assessment, intervention monitoring, and feedback during postural re-education.

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Section: Discussionmentioning

confidence: 99%

Preliminary study: reliability of the spinal wheel. A novel device to measure spinal postures applied to sitting and standing

et al. 2009

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“…Within the sagittal plane, habitual poor postures include forward head and flexed-relaxed postures 4,6) . Both of these positions are easily adopted by computer users due to their low muscular effort, and they result in increased load on passive paraspinal structures 6,7) . Increased forward head, specifically, which combines lower cervical flexion and upper cervical extension with rounded shoulders, might result in weakness of the cervical extensors as well as increased compressive forces in the articulations of the cervical spine 8,9) .…”

mentioning

confidence: 99%

“…Previous research has presented data on the positive relationship between activation of the upper trapezius muscle and flexion of the cervical spine muscles during computer operation 8,10,11) . It has been documented that the disadvantages of flexedrelaxed sitting are that it leads to increased disc pressure, tension in passive structures and flexion relaxation within the pain-free population 7,12) . Therefore, the definition of an ideal sitting posture to avoid poor posture has been discussed in biomechanical and ergonomic arenas.…”

mentioning

confidence: 99%

Effect of EMG‐based Feedback on Posture Correction during Computer Operation

Park

Yoo

2012

Journal of Occupational Health

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Effect of EMG-based Feedback on PostureCorrection during Computer Operation: Se-yeon PARK, et al. Department of Physical Therapy, The Graduate School, Inje University, Republic of Korea-Objective: The aim of this study was to investigate the effects of an EMG-based feedback device on the human musculoskeletal system by assessing the kinematics of the lumbar and cervical regions during computer operation. Methods: Using an EMG device, measurements were collected under four conditions: with feedback from the upper trapezius muscle, from the L4-erector spinae muscles and from both and without feedback (control). During periods of 15 min of computer operation, kinematic data were collected using the Zebris motion analysis system to investigate 14 university employees. Results: Feedback assessment effectively reduced the kinematic changes in the sagittal plane compared with the control (p<0.05). Feedback from the L4 erector spinae reduced the trunk flexion and forward head angles, which were significantly different compared with those under the feedback from the upper trapezius and the control conditions (p<0.05). Conclusion: We observed that the use of an EMG-based feedback device was effective in reducing habitual forward head and flexed-relaxed postures during computer operation. Additionally, posture correction from the lumbar region could be a way to reduce forward head posture as well as flexed-relaxed posture. (J Occup Health 2012; 54: 271-277)

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“…This may ultimately contribute to disc degeneration [29] and may consequently cause LBP. Furthermore, the flexion-relaxation phenomenon is present during slumped sitting [44], so there is very low active muscular support for the lumbar spine. Because of this very low activation, the load is transmitted by passive structures such as the ligaments and IVD.…”

Section: Introductionmentioning

confidence: 99%

“…There has also been much interest in the stability of the lumbar spine and its relation to LBP [23]. On the other hand, a review on posture reported that there are still controversies and little evidence to support the claims of benefits of ideal posture or the suggestion that poor posture will lead to LBP [44].…”

Section: Introductionmentioning

confidence: 99%

Influence of trunk muscle co-contraction on spinal curvature during sitting

Watanabe

Kobara

Yoshimura

et al. 2014

BMR

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Background and purpose: Slumped sitting is known to increase disc pressure and aggravate chronic low back pain. In addition, it has been recognized that co-contraction of the deep spine-stabilizing muscles enhances lumbar segmental stability and the sacro-iliac joint. The purpose of this study was to compare the electromyographic (EMG) activity of the trunk muscles and the muscle thickness of the transverse abdominis (TrA) during slumped sitting with the same parameters during co-contraction and investigate how co-contraction influences spinal curvature.Subjects and methods: Nine healthy male volunteers participated in the study. EMG signals were recorded during both sitting postures. In order to measure the muscle thickness of the TrA, ultrasound images were captured. While the subjects performed both sitting postures, spinal curvature was measured using a hand-held device.Results: Significantly more activity of the trunk muscles, with the exception of the rectus abdominis muscle, and significantly greater muscle thickness of the TrA were observed during co-contraction of the trunk muscles than during slumped sitting.Co-contraction also resulted in significantly increased lumbar lordosis and a greater sacral angle when compared to slumped sitting.Conclusion: In this study, it was demonstrated that the instructions given to the subjects on co-contraction of the trunk muscles during sitting increased muscle activity with the exception of the rectus abdominis muscle, muscle thickness of the TrA, and lumbar lordosis.

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Evaluation of the Flexion Relaxation Phenomenon of the Trunk Muscles in Sitting

Cited by 90 publications

References 34 publications

Preliminary study: reliability of the spinal wheel. A novel device to measure spinal postures applied to sitting and standing

Preliminary study: reliability of the spinal wheel. A novel device to measure spinal postures applied to sitting and standing

Effect of EMG‐based Feedback on Posture Correction during Computer Operation

Influence of trunk muscle co-contraction on spinal curvature during sitting

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