A Decreased Ability to Relax Between Repetitive Muscle Contractions in Patients with Chronic Symptoms After Whiplash Trauma of the Neck

Fredin, Ylva; Elert, Jessica; Britschgi, Nina; Nyberg, Vanja; Vaher, Anne; Gerdle, B

doi:10.1300/j094v05n02_05

Cited by 42 publications

(44 citation statements)

References 12 publications

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“…41 However, increased activity in the levator scapulae and the rhomboid muscles 28 may explain the increased scapular posterior tilt observed in the IONP group (FiGurE 5). 41 A difference in the activity of the upper trapezius has been found between patients with WAD and IONP, where patients with WAD had a tendency for higher and longer muscle activation patterns of the trapezius during upper limb tasks, 37 reduced ability to relax after tasks, 13 and significantly higher EMG amplitude in the muscle compared to patients with IONP. 10 However, reduced activity has been observed in the upper trapezius in patients with acute WAD (within 6 months from injury) during upper limb tasks.…”

Section: Discussionmentioning

confidence: 99%

Altered Scapular Orientation During Arm Elevation in Patients With Insidious Onset Neck Pain and Whiplash-Associated Disorder

Helgadottir¹,

Kristjansson²,

Mottram³

et al. 2010

J Orthop Sports Phys Ther

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Section: Discussionmentioning

confidence: 99%

Altered Scapular Orientation During Arm Elevation in Patients With Insidious Onset Neck Pain and Whiplash-Associated Disorder

Helgadottir¹,

Kristjansson²,

Mottram³

et al. 2010

J Orthop Sports Phys Ther

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“…A signi®cantly higher SAR at the endurance level was found for the shoulder muscles of patients with dierent kinds of chronic pain conditions (Elert et al 1992a, b;Fredin et al 1997). SAR is negatively correlated with biomechanical output, and increases with angular velocity (Elert et al 1992a, b).…”

Section: Sarmentioning

confidence: 99%

“…®bromyalgia, work-related myalgia and chronic whiplash-associated disorders) have a signi®cantly reduced ability to relax their muscles in the pauses between maximum repetitive concentric isokinetic contractions compared to clinically healthy subjects (Elert et al 1992b;Fredin et al 1997). The relative inability to relax was indicated by the signal amplitude ratio (SAR); the ratio between the RMS level during the passive part of the movement cycle and the RMS level during the active part of the contraction cycle.…”

Section: Introductionmentioning

confidence: 99%

The influences of muscle fibre proportions and areas upon EMG during maximal dynamic knee extensions

Gerdle¹,

Karlsson²,

Crenshaw

et al. 2000

Eur J Appl Physiol

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This study is an investigation of the relationship between muscle morphology and surface electromyographic (EMG) parameters [mean frequency of the power spectrum (MNF), signal amplitude (root mean square, RMS) and the signal amplitude ratio (SAR; i.e. the ratio between the RMS level during the passive part of the contraction cycle and the RMS level during the active part of the contraction cycle)] during 100 maximal dynamic knee extensions at 90 degrees. s(-1). Each contraction cycle comprised of 1 s of active knee extension and 1 s of passive knee flexion. The surface EMG was recorded from the vastus lateralis muscle. Twenty clinically healthy subjects participated in the study, and muscle biopsy samples of the vastus lateralis were obtained from 19 of those subjects. The relationships between muscle morphology and EMG were investigated at three stages of the test: initially, during the fatigue phase (initial 40 contractions), and at the endurance level (the final 50 contractions). Major findings on correlations are that SAR and MNF tended to correlate positively with the proportion of type 1 fibres, and RMS correlated positively with the proportion of type 2 muscle fibres. The muscle fibre areas showed little correlation with the EMG variables under investigation. The results of the present study showed that the three EMG variables of a dynamic endurance test that were investigated (RMS, MNF and SAR) were clearly correlated with the proportions of the different fibre types, but only to a small extent with fibre areas. These findings contradict some of the theoretical models of the EMG, especially for parameters in the frequency domain.

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“…7 It is plausible that the morphometrical changes in the oropharynx are a consequence of both changes in structure and function of the neck muscles secondary to pain and disability. 6,15,20,23,26 Patients with chronic whiplash demonstrate higher levels of electromyographic (EMG) activity in their neck flexor (anterior scalenes, sternocleidomastoid) and shoulder girdle (upper trapezius) muscles with functional tasks. 14,21,24 Such trauma-related muscular responses develop in virtually all subjects with whiplash injury soon after the injury event (within 1 month).…”

Section: T T Resultsmentioning

confidence: 99%

Magnetic Resonance Imaging Changes in the Size and Shape of the Oropharynx Following Acute Whiplash Injury

Elliott

Pedler

Theodoros

et al. 2012

J Orthop Sports Phys Ther

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Up to 50% of those who sustain a whiplash injury from a motor vehicle collision (MVC) transition from acute to chronic pain, 5 which results in a substantial personal and economic burden. 2 The variability of reported symptoms, including neck pain, complaints of dizziness, otological and ocular disturbances, headache, loss of concentration and short-term memory, anxiety, insomnia, and depression, 1,7,26,[30][31][32][33][34][35] can challenge even the most astute clinician. Further complicating the clinical picture is the presence of less-recognized symptoms, such as hoarseness, difficulty swallowing, 1,22 or voice changes, in chronic whiplash. 3 In general, such symptoms are not commonly associated with a whiplash injury, and the specific underlying causes for such changes are unknown. The advent and use of higherfield magnetic resonance imaging (MRI) systems in the research laboratory, however, have provided a foundation for quantifying physiologic processes (eg, muscle degeneration, [8][9][10][11][12] function, 4,13,25 and altered oropharyngeal morphometry 7 ) that could be associated with the T T STUDY DESIGN: Prospective longitudinal. T T OBJECTIVE:To quantify the temporal development of magnetic resonance imaging changes in oropharyngeal morphometry in subjects with varying levels of disability following a whiplash injury. T T BACKGROUND:A recent cross-sectional investigation has identified reductions in the size and shape of the oropharynx in subjects with chronic whiplash-related disability when compared to healthy controls. The temporal development of such changes and their relationship to persistent disability have yet to be investigated. T T METHODS:Forty-one subjects (30 women) with acute whiplash injury were included. Repeatedmeasures T1-weighted magnetic resonance imaging was used to measure and compare cross-sectional area (CSA) in square millimeters and shape ratio (SR) of the oropharynx at 4 weeks, 3 months, and 6 months postinjury. Subjects were classified at 6 months by their Neck Disability Index scores into the following categories: recovered (less than 8%), mild disability (10%-28%), and moderate/ severe disability (greater than 30%). The effects of time and group and the interaction effect of group by time on oropharynx morphometry (CSA, SR) were investigated using repeated-measures, linear, mixed-model analysis. Based on previous research findings, age, gender, and body mass index were entered into the analyses as covariates. Where significant main or interaction effects were detected, pairwise comparisons were performed to investigate specific differences in the dependent variable between groups and within groups over time. T T RESULTS:There was a significant interaction effect for group by time for both the CSA and SR values. Age significantly influenced SR (P = .024) and body mass index significantly influenced CSA (P = .001). There was no difference in CSA or SR across all groups at 4 weeks postinjury. However, at 6 months, CSA was significantly different between the recovered group an...

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A Decreased Ability to Relax Between Repetitive Muscle Contractions in Patients with Chronic Symptoms After Whiplash Trauma of the Neck

Cited by 42 publications

References 12 publications

Altered Scapular Orientation During Arm Elevation in Patients With Insidious Onset Neck Pain and Whiplash-Associated Disorder

Altered Scapular Orientation During Arm Elevation in Patients With Insidious Onset Neck Pain and Whiplash-Associated Disorder

The influences of muscle fibre proportions and areas upon EMG during maximal dynamic knee extensions

Magnetic Resonance Imaging Changes in the Size and Shape of the Oropharynx Following Acute Whiplash Injury

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