Trapezius Muscle In Subjects Research Articles

Effects of lumbar lordosis assistive support on craniovertebral angle and mechanical properties of the upper trapezius muscle in subjects with forward head posture

[Purpose] The aim of this study was to investigate the effect of lumbar lordosis assistive support (LLAS) on craniovertebral angle (CVA) and mechanical properties of the upper trapezius (UT) muscle in subjects with forward head posture (FHP). [Subjects and Methods] This study recruited 20 subjects with FHP. CVA and muscle tone, viscoelasticity, and stiffness of the UT were measured using Myoton in all subjects in a sitting position with LLAS and in a neutral sitting position. The order of measurements was randomized and the mean values were calculated twice. [Results] The sitting position with LLAS showed a significantly greater improvement than the neutral sitting position with regard to CVA and muscle tone, viscoelasticity, and stiffness of the UT. [Conclusion] We suggest that the sitting position using LLAS induces the maintenance of normal neck posture and a reduction in the muscle tone of the UT in the subjects with FHP.

둥근 어깨 자세를 가진 자의 등세모근 위 섬유의 압통점에 975-nm GaAlAs 저출력레이저 적용에 대한 즉각적인 효과

PURPOSE: The purpose of our study was to compare a 975-nm, 500-mW GaAlAs low-level laser therapy versus placebo low-level laser therapy with regard to the immediate changes on the myofascial trigger point of the dominant upper trapezius muscle in subjects with rounded shoulder posture. METHODS: Thirty-two male college students with rounded shoulder posture and shoulder pain consented to participate in the experiment. The subjects were randomly assigned to a 2-minute procedure with either an active GaAlAs low-level laser or a placebo GaAlAs low-level laser. The pressure-pain threshold and visual analog scale on tenderness at 3 kg were measured with an algometer before and after the laser treatments. RESULTS: The active GaAlAs low-level laser group showed significant changes in pressure-pain threshold and visual analog scale on tenderness at 3 kg (p0.05). CONCLUSION: An immediate effect was observed in pressure-pain threshold and visual analog scale on tenderness at 3 kg following a 2-minute application () of a 975-nm, 500-mW GaAlAs low-level laser to the myofascial trigger point of the dominant upper trapezius muscle in patients with rounded shoulder posture.

Selective activation of intra-muscular compartments within the trapezius muscle in subjects with Subacromial Impingement Syndrome. A case-control study

Neuromuscular control of the scapular muscles is important in the etiology of shoulder pain. Electromyographical (EMG) biofeedback in healthy people has been shown to support a selective activation of the lower compartment of the trapezius muscle, specifically. The aim of the present paper was to investigate whether patients with Subacromial Impingement Syndrome (SIS) were able to selectively activate the individual compartments within the trapezius muscle, with and without EMG biofeedback to the same extent as healthy controls (No-SIS).Fifteen SIS and 15 No-SIS participated in the study. Sessions with and without visual biofeedback were conducted. Surface EMG was recorded from four compartments of the trapezius muscle. Selective activation was defined as activation above 12% with other muscle parts below 1.5% or activation ratio at or above 95% of the total activation. Without biofeedback significantly fewer SIS subjects than No-SIS achieved selective activation (p=0.02–0.03).The findings of the study show that without biofeedback No-SIS had a superior scapular muscle control. However, when provided with visual EMG feedback the SIS group performed equally well as the No-SIS group. This indicated that individuals with SIS may benefit from biofeedback training to gain control of the neuromuscular function of the scapular muscle.

Biochemicals Associated With Pain and Inflammation are Elevated in Sites Near to and Remote From Active Myofascial Trigger Points

Shah JP, Danoff JV, Desai MJ, Parikh S, Nakamura LY, Phillips TM, Gerber LH. Biochemicals associated with pain and inflammation are elevated in sites near to and remote from active myofascial trigger points. ObjectivesTo investigate the biochemical milieu of the upper trapezius muscle in subjects with active, latent, or absent myofascial trigger points (MTPs) and to contrast this with that of the noninvolved gastrocnemius muscle. DesignWe used a microanalytic technique, including needle insertions at standardized locations in subjects identified as active (having neck pain and MTP), latent (no neck pain but with MTP), or normal (no neck pain, no MTP). We followed a predetermined sampling schedule; first in the trapezius muscle and then in normal gastrocnemius muscle, to measure pH, bradykinin, substance P, calcitonin gene-related peptide, tumor necrosis factor alpha, interleukin 1β (IL-1β), IL-6, IL-8, serotonin, and norepinephrine, using immunocapillary electrophoresis and capillary electrochromatography. Pressure algometry was obtained. We compared analyte concentrations among groups with 2-way repeated-measures analysis of variance. SettingA biomedical research facility. ParticipantsNine healthy volunteer subjects. InterventionsNot applicable. Main Outcome MeasuresPreselected analyte concentrations. ResultsWithin the trapezius muscle, concentrations for all analytes were higher in active subjects than in latent or normal subjects (P<.002); pH was lower (P<.03). At needle insertion, analyte concentrations in the trapezius for the active group were always higher (pH not different) than concentrations in the gastrocnemius muscle. At all times within the gastrocnemius, the active group had higher concentrations of all analytes than did subjects in the latent and normal groups (P<.05); pH was lower (P<.01). ConclusionsWe have shown the feasibility of continuous, in vivo recovery of small molecules from soft tissue without harmful effects. Subjects with active MTPs in the trapezius muscle have a biochemical milieu of selected inflammatory mediators, neuropeptides, cytokines, and catecholamines different from subjects with latent or absent MTPs in their trapezius. These concentrations also differ quantitatively from a remote, uninvolved site in the gastrocnemius muscle. The milieu of the gastrocnemius in subjects with active MTPs in the trapezius differs from subjects without active MTPs.

Altered control of the trapezius muscle in subjects with non-traumatic shoulder instability

Objective: Reflexes of shoulder girdle muscles such as trapezius are evoked from muscle afferents supplying the forearm and hand in healthy subjects. These reflexes are thought to aid the stability of the shoulder during use of the arm and hand [Alexander CM, Harrison PJ. Reflex connections from forearm and hand afferents to shoulder girdle muscles in humans. Exp Brain Res 2003;148: 277–282.]. With this in mind, the objective of this investigation was to examine this trapezius reflex in subjects with non-traumatic shoulder instability (NTSI). Methods: The occurrence and alteration to this supraspinal reflex pathway were investigated using electrical stimulation of the ulnar and the spinal accessory nerves as well as magnetic stimulation of the trapezius motor cortex. These results were compared to a healthy group. Results: The reflexes to lower trapezius were not usually observed in subjects with NTSI. When evoked, the frequency of occurrence was 27% compared to 87% in a healthy population ( p < 0.002). When present, the latency of this lower trapezius reflex was later than that evoked in the healthy group (62.8 ms ± 28.1 ms and 38.4 ms ± 3.6 ms, respectively; p < 0.009). Although both the conduction velocity of the effective afferents and the latency of the M response to lower trapezius did not differ to the healthy group ( p < 0.24 and 0.54, respectively), the latency and threshold of the corticospinal evoked potential of lower trapezius did differ (16.7 ms ± 4.7 ms vs 11.2 ms ± 1.8 ms; p = 0.006; 57% ± 15.8% vs 36% ± 7.6%, p = 0.003). Overall, these results contrast to these measures of control of upper trapezius, which did not differ to a healthy group. Conclusions: The delay or absence of these reflexes and the delay and change in threshold of the corticospinal response in lower trapezius in subjects with NTSI indicate that the feedback mechanisms that aid shoulder girdle stability, and the voluntary control of lower trapezius are not as proficient in these subjects. Significance: The control of lower trapezius should be considered when treating people with NTSI.

Continuous, intermitted and sporadic motor unit activity in the trapezius muscle during prolonged computer work

The Cinderella hypothesis postulates the continuous activity of specific motor units (MUs) during low-level muscle contraction. The MUs may become metabolically overloaded, with the subject developing muscle pain and strain. The hypothesis requires MUs that are active for a time long enough to actually damage muscle fibers. The aim of this study was to determine if there are continuously active MUs in the right trapezius muscle during normal computer work using a computer mouse. Fourteen healthy subjects executed an interactive computer-learning program (ErgoLight) for 30 min. Six-channel intramuscular EMG and two-channel surface EMG signals were recorded from two positions of the trapezius muscle. Decomposition was achieved with automated, multi-channel, long-term decomposition software (EMG-LODEC). In two out of the 14 subjects, three MUs were continuously active throughout the 30 min. Although the majority of the MUs were active during only part of the experimental session, an ordered on–off behavior (e.g. substitution) pattern was not observed. As long-lasting activity was verified in some subjects, the results support the Cinderella hypothesis. However, it cannot be concluded here how long the MUs could stay active. If continuous activity overloads low threshold MUs, the potential exists for selective fibre injuries in low threshold MUs of the trapezius muscle in subjects exposed to long-term computer work.

Manual Palpation and Pain Threshold in Female Office Employees With and Without Neck-Shoulder Symptoms

The aim of this study was to quantify myofascial tenderness by using manual palpation and the dolorimeter on female office employees with disturbing neck-shoulder symptoms (DS) and no or occasional neck-shoulder symptoms (NOS). The association among neck-shoulder symptoms, pain threshold, and age was also analyzed. The cross-sectional study of female office employees selected on a voluntary basis from two offices. The manual palpation of neck-shoulder muscles was analyzed at 16 palpation points defined before the examination. The pain threshold (PT) was measured at four trigger areas of trapezius and levator muscles. 160 female office employees with mean age 41 (21-60) years; height was 163 (149-178) cm; and weight was 62 (45-115) kg. Manual palpation findings of neck-shoulder muscles at 16 defined palpation points and PT measurement of trigger areas in trapezius and levator muscles by a dolorimeter. The mean number of tender points was 7.25 (SD, 4.5) in subjects with DS and 3.44 (SD, 3.8) in subjects with NOS; the difference was significant (p < 0.0001). Suboccipital and trapezius muscles were tender in most cases in both symptom groups. The PTs of trapezius and levator muscles were significantly lower in subjects with DS than in subjects with NOS (p < 0.0001-0.0005). The PT of the trapezius muscles in subjects > or = 39 years old with DS was significantly lower than in those with NOS (p < 0.0007-0.0402). The PT of subjects with DS was lower in subjects 39 years old and older than in younger subjects, while the PT in subjects with NOS was higher in older subjects than in younger ones; the differences were statistically nonsignificant. Suboccipital and trapezius muscles are often tender in subjects with DS and in those with NOS. The finding that the PT of the trapezius muscle in older subjects with DS decreases while the PT in subjects with NOS increases is interesting and needs further investigation.

Effect of intermittent, supine cervical traction on the myoelectric activity of the upper trapezius muscle in subjects with neck pain.

This study was undertaken to compare the myoelectric activity of the upper trapezius muscle before, during, and after intermittent, supine cervical traction. Twelve people with diagnosed disease or injury of the cervical spine served as subjects. Electromyographic recordings were taken from the upper trapezius muscle with bipolar surface electrodes. The subjects were treated with 20 minutes of intermittent, cervical traction at a force of 8% of their body weight. Recordings were taken with the subjects in the supine position before the traction, during one pull and release phase of the 10th and 20th minutes of traction, and after completion of the traction treatment. An analysis of variance with repeated measures showed no significant differences in the myoelectrical activity during the six time periods measured. The results of this study do not support the clinical use of intermittent, supine traction to produce cervical muscle relaxation.