Are Abnormalities in Sarcoplasmic Reticulum Calcium Cycling Properties Involved in Trapezius Myalgia?: Case Studies on Three Females

Effects of transcutaneous electrical nervous stimulation (TENS) associated with vocal therapy on musculoskeletal pain of women with behavioral dysphonia: A randomized, placebo-controlled double-blind clinical trial

Recently, electrical stimulation in vocal rehabilitation has been the subject of studies. This treatment has shown promising results regarding the decrease of vocal/laryngeal symptoms, pain and the improvement of vocal tension. In addition to decreasing pain symptoms, TENS treatments may lead to muscle relaxation. There is no data on the effects of this resource as a vocal therapy in women with behavioral dysphonia. Research in this area may provide evidence to assist the clinical decision related to the treatment of women with complaints of behavioral dysphonia and musculoskeletal pain.

OBJECTIVE

To verify the effects of low-frequency TENS in association with vocal therapy on musculoskeletal pain in women with behavioral dysphonia.

METHODS

Participants included 27 women with vocal nodules randomized into two groups. The experimental group (EG) - 13 women received 12 sessions of TENS (pulse of 200 μs, frequency at 10 Hz, in motor threshold) with electrodes placed bilaterally on the trapezius muscle and submandibular area for 20 min followed by 30 min of vocal therapy, and the control group (CG) - 14 women received 12 sessions of 20 min of a placebo TENS followed by 30 min of vocal therapy. We investigated the frequency and intensity of the musculoskeletal pain in several body regions, as well as the intensity of pain at rest and in the application of pressure with an algometer applied to the descending fibers of the trapezius muscle. The pressure-pain threshold (PPT) was also investigated. All evaluations occurred before, immediately after, and at one and three months after treatment in both groups.

RESULTS

We observed a reduction in the frequency of pain in the larynx after treatment of both groups, but only the EG showed a decrease in pain intensity in this region. It was verified with an algometer to the trapezius muscle that the electrical stimulation associated with the vocal therapy decreased the intensity of pain during the application of pressure and increased the PPT. There were no significant differences with regard to variables investigated in the comparison between the interventions. On the other hand, there was decreased pain in the trapezius muscle for the EG in comparison to the pre- and post-intervention.

CONCLUSION

The vocal therapyprogram reduced the frequency and intensity of the musculoskeletal pain in the regions proximal to the larynx of women with behavioral dysphonia. In addition, TENS followed by vocal therapy increased the threshold of sensitivity to muscular pain in the trapezius, demonstrating that it is a good resource to use in conjunction with traditional vocal therapy in cases of behavioral dysphonia associated with pain and muscle tension.

Neuronal nitric oxide synthase is dislocated in type I fibers of myalgic muscle but can recover with physical exercise training

Trapezius myalgia is the most common type of chronic neck pain. While physical exercise reduces pain and improves muscle function, the underlying mechanisms remain unclear. Nitric oxide (NO) signaling is important in modulating cellular function, and a dysfunctional neuronal NO synthase (nNOS) may contribute to an ineffective muscle function. This study investigated nNOS expression and localization in chronically painful muscle. Forty-one women clinically diagnosed with trapezius myalgia (MYA) and 18 healthy controls (CON) were included in the case-control study. Subsequently, MYA were randomly assigned to either 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 15), or health information (REF, n = 8). Distribution of fiber type, cross-sectional area, and sarcolemmal nNOS expression did not differ between MYA and CON. However, MYA showed increased sarcoplasmic nNOS localization (18.8 ± 12 versus 12.8 ± 8%, P = 0.049) compared with CON. SST resulted in a decrease of sarcoplasm-localized nNOS following training (before 18.1 ± 12 versus after 12.0 ± 12%; P = 0,027). We demonstrate that myalgic muscle displays altered nNOS localization and that 10 weeks of strength training normalize these disruptions, which supports previous findings of impaired muscle oxygenation during work tasks and reduced pain following exercise.

Excitation–contraction coupling properties in women with work-related myalgia: a preliminary study

We investigated the potential role of selected excitation–contraction coupling processes in females with work-related myalgia (WRM) by comparing WRM with healthy controls (CON) using tissue from extensor carpi radialis brevis (ECRB) and trapezius (TRAP) muscles. For the ECRB, age (mean ± SE) was 29.6 ± 3.5 years for CON (n = 9) and 39.2 ± 2.8 years for WRM (n = 13), while for the TRAP, the values were 26.0 ± 2.1 years for CON (n = 7) and 44.6 ± 2.9 years for WRM (n = 11). For the sarcoplasmic reticulum (SR) of the ECRB, WRM displayed concentrations (nmol·(mg protein)−1·min−1) that were lower (P < 0.05) for Total (202 ± 4.4 vs 178 ± 7.1), Basal (34 ± 1.6 vs 30.1 ± 1.3), and maximal Ca2+-ATPase activity (Vmax, 168 ± 4.9 vs 149 ± 6.3), and Ca2+-uptake (5.06 ± 0.31 vs 4.13 ± 0.29), but not SERCA1a and SERCA2a isoforms, by comparison with CON. When age was incorporated as a co-variant, Total, Basal, and Ca2+-uptake remained different from CON (P < 0.05), but not Vmax (P = 0.13). For TRAP, none of the ATPase properties differed between groups (P > 0.05) either before or following adjustment for age. No differences (P > 0.05) were observed between the groups for Ca2+-release in the SR for either TRAP or ECRB. Similarly, no deficiencies, regardless of muscle, were noted for either the Na+–K+-ATPase content or the α and β subunit isoform distribution in WRM. This preliminary study provides a basis for further research, with expanded numbers, investigating the hypothesis that abnormalities in SR Ca2+-regulation are involved in the cellular etiology of WRM.

A pilot study to determine whether differences exist in histochemical properties between the trapezius and extensor carpi radialis brevis muscles in women with work-related myalgia

To investigate fibre-type abnormalities in women with work-related myalgia (WRM), tissue samples were extracted from their trapezius (TRAP) and the extensor carpi radialis brevis (ECRB) muscles and compared with healthy controls (CON). For the ECRB samples (CON, n = 6; WRM, n = 11), no differences (P > 0.05) were found between groups for any of the properties examined, namely fibre-type (I, IIA, IIX, IIAX) distribution, cross-sectional fibre area, capillary counts (CC), capillary to fibre area ratio, and succinic dehydrogenase activity. For the TRAP samples (CON, n = 6; WRM, n = 8), the only difference (P < 0.05) observed between groups was for CC (CON > WRM), which was not statistically significant (P > 0.05) when age was used a covariant. A comparison of the properties of these 2 muscles in the CON group indicated a higher (P < 0.05) and lower (P < 0.05) percentage of type I and type IIA fibres, respectively, in the TRAP as well as higher (P < 0.05) CC, which was not specific to fibre type. These preliminary results suggest that the properties employed to characterize fibre types do not differentiate CON from WRM for either the TRAP or ECRB. As a consequence, the role of inherent fibre-type differences between these muscles in the pathogenesis of WRM remains uncertain.

High-intensity strength training improves function of chronically painful muscles: case-control and RCT studies

Aim. This study investigates consequences of chronic neck pain on muscle function and the rehabilitating effects of contrasting interventions. Methods. Women with trapezius myalgia (MYA, n = 42) and healthy controls (CON, n = 20) participated in a case-control study. Subsequently MYA were randomized to 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 16), or a reference group without physical training (REF, n = 8). Participants performed tests of 100 consecutive cycles of 2 s isometric maximal voluntary contractions (MVC) of shoulder elevation followed by 2 s relaxation at baseline and 10-week follow-up. Results. In the case-control study, peak force, rate of force development, and rate of force relaxation as well as EMG amplitude were lower in MYA than CON throughout all 100 MVC. Muscle fiber capillarization was not significantly different between MYA and CON. In the intervention study, SST improved all force parameters significantly more than the two other groups, to levels comparable to that of CON. This was seen along with muscle fiber hypertrophy and increased capillarization. Conclusion. Women with trapezius myalgia have lower strength capacity during repetitive MVC of the trapezius muscle than healthy controls. High-intensity strength training effectively improves strength capacity during repetitive MVC of the painful trapezius muscle.