Lower Trapezius Muscle Strength in Individuals With Unilateral Neck Pain
Descriptive and within-subject comparative study.
To examine lower trapezius muscle strength in individuals with unilateral neck pain.
Previous research has established the presence of reduced cervical flexor, extensor, and rotator muscle strength in individuals with neck pain. Some authors have suggested that individuals with neck pain have limited strength of the lower trapezius muscle, yet no research has investigated this claim.
Twenty-five individuals with unilateral neck pain participated in this study. Participants completed the Northwick Park Neck Pain Questionnaire (NPQ) as a measure of disability. Side of neck pain, duration of neck pain, and hand dominance were recorded. Lower trapezius muscle strength was assessed bilaterally in each participant, using a handheld dynamometer.
A significant difference in lower trapezius strength was found between sides (P<.001), with participants demonstrating an average of 3.9 N less force on the side of neck pain. The tested levels of association between NPQ score and percent strength deficit (r = -0.31, P = .13), and between symptom duration and percent strength deficit (r = -0.25, P = .22), were not statistically significant. No significant association was found between hand dominance and side of stronger lower trapezius (P = .59).
The results of this study demonstrate that individuals with unilateral neck pain exhibit significantly less lower trapezius strength on the side of neck pain compared to the contralateral side. This study suggests a possible association between lower trapezius muscle weakness and neck pain.
Available from: Shannon MBravo Petersen
- "Scapulothoracic (ST) muscle impairment has been associated with neck pain. There is evidence of weakness or altered activity in the middle trapezius (MT), lower trapezius (LT) and serratus anterior (SA) muscles in patients with neck pain (Helgadottir et al., 2010; Petersen and Wyatt, 2011; Shahidi et al., 2012; Zakharova-Luneva et al., 2012; Petersen et al., 2016). Although a combination of manual therapy (thrust and non-thrust manipulation) and exercise has been advocated as an intervention (Miller et al., 2010), the influence of manual therapy on the ST muscles has not been established for this population. "
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Scapulothoracic muscle weakness has been associated with neck pain (NP). Little evidence exists regarding lower trapezius (LT), middle trapezius (MT) and serratus anterior (SA) strength in this population. LT strength changes have been observed following thoracic manipulation in healthy subjects. The purpose of the present study was to examine scapulothoracic strength changes following cervical manipulation in subjects with NP.
Twenty-two subjects with NP and 17 asymptomatic control (AC) subjects underwent strength testing of the LT, MT and SA using a hand-held dynamometer. Subjects with NP were treated with passive intervertebral neck manipulation and neck range of motion exercises. The AC group received no intervention. Strength testing was repeated after manipulation, then 48 and 96 hours later. Change scores were calculated for strength over time. Paired t-tests were done for strength change between painful and non-painful sides in the NP group. Independent t-tests were done for strength change between the NP group and AC group.
There was no significant difference between groups for age, gender, hand dominance or body mass index. Mean (standard deviation) symptom duration for subjects in the NP group was 43.27 (62.71) months. There was no significant difference in strength change over time between painful and non-painful sides in the NP group for any muscle; however, there was a significant difference in strength change over time between those in the NP group and AC group for the LT (p < 0.01), SA (p < 0.01) and MT (p < 0.01).
Scapulothoracic muscle strength improvements were observed in both extremities following passive intervertebral neck manipulation and neck range of motion exercises. Improvements lasted up to 96 hours following manipulation, even though no strengthening exercises were prescribed.
Manipulation and range of motion should be considered as a component of intervention programmes for patients with NP and scapulothoracic muscle weakness. Future studies should compare manipulation alone to exercise alone to determine impact on strength. Copyright © 2016 John Wiley & Sons, Ltd.
Available from: Per-Anders Fransson
- "A pronounced thoracic kyphosis may reduce spinal movement flexibility , and might consequently change the prerequisites when using the neck and shoulder muscles and joints (Greenfield et al. 1995; Quek et al. 2013). Pain and over-activity in the upper trapezius (UT) muscles is often found together with less strength in lower trapezius (LT) and serratus anterior (SA) muscles in subjects with neck and shoulder pain (Petersen and Wyatt, 2011; Struyf et al. 2014). Increased muscle activity in especially the upper and middle trapezius portion coincides with pain and movement disability in the neck and shoulder region (Hagg and Astrom 1997; Schulte et al. 2006; Szeto et al. 2005; Wegner et al. 2010). "
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Long-term use of unfavorable postures, congenital deformations and degenerative processes associated with aging or disease may generate an increased thoracic curvature resulting in pain and disability. We wanted to examine whether a slouched postural alignment with increased thoracic kyphosis changes the shoulder kinematics and muscle activity in upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) during arm elevation. The aim was to determine if a slouched posture influences range of motion, muscle activation patterns, maximal muscle activity and the total muscle work required when performing arm elevations.
Twelve male subjects (23.3 ± 1.5 years) performed maximum arm elevations in upright and slouched postures. A combined 3D movement and EMG system recorded arm movements and spine curvature simultaneously with EMG activity in the UT, LT and SA.
Slouched posture affected the biomechanical conditions by significantly decreasing maximum arm elevation by ~15° (p < 0.001) and decreasing arm movement velocity by ~8 % during movements upwards (p < 0.001) and downwards (p = 0.034). The peak muscle activity increased in all muscles: UT (p = 0.034, +32.3 %), LT (p = 0.001, +48.6 %) and SA (p = 0.007, +20.9 %). The total muscle work increased significantly in the slouched posture during movements upwards: UT (p = 0.003, +36.6 %), LT (p < 0.001, +89.0 %), SA (p = 0.002, +19.4 %) and downwards: UT (p = 0.012, +29.8 %) and LT (p < 0.001, +122.5 %).
An increased thoracic kyphosis was found associated with marked increased physical costs when performing arm movements. Hence, patients suffering from neck-shoulder pain and disability should be investigated and treated for defective thoracic curvature issues.
Available from: Bahar Shahidi
- "Recent studies have demonstrated the utility of hand held dynamometry (HHD) as a robust alternative to MMT which shows acceptable reliability for a variety of different tests of isometric strength across several muscle groups
[9,13]. Although scapulothoracic muscles such as the rhomboids, middle trapezius, and lower trapezius are thought to contribute to postural stability of the cervical spine and reduce biomechanical loading of cervicoscapular musculature
[14,15], we are aware of only one study that has investigated the use of HHD to measure scapulothoracic muscle strength in individuals with neck pain
. It is currently not known whether scapulothoracic muscle strength is impaired in patients with chronic neck pain compared to healthy individuals, or whether the strength of these muscles can be reliably assessed over time. "
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Clinicians frequently rely on subjective categorization of impairments in mobility, strength, and endurance for clinical decision-making; however, these assessments are often unreliable and lack sensitivity to change. The objective of this study was to determine the inter-rater reliability, minimum detectable change (MDC), and group differences in quantitative cervicothoracic measures for individuals with and without chronic neck pain (NP).
Nineteen individuals with NP and 20 healthy controls participated in this case control study. Two physical therapists performed a 30-minute examination on separate days. A handheld dynamometer, gravity inclinometer, ruler, and stopwatch were used to quantify cervical range of motion (ROM), cervical muscle strength and endurance, and scapulothoracic muscle length and strength, respectively.
Intraclass correlation coefficients for inter-rater reliability were significantly greater than zero for most impairment measures, with point estimates ranging from 0.45 to 0.93. The NP group exhibited reduced cervical ROM (P ≤ 0.012) and muscle strength (P ≤ 0.038) in most movement directions, reduced cervical extensor endurance (P = 0.029), and reduced rhomboid and middle trapezius muscle strength (P ≤ 0.049).
Results demonstrate the feasibility of obtaining objective cervicothoracic impairment measures with acceptable inter-rater agreement across time. The clinical utility of these measures is supported by evidence of impaired mobility, strength, and endurance among patients with NP, with corresponding MDC values that can help establish benchmarks for clinically significant change.
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