The immediate effect of multiple mechanical impulses on electromyography and pressure pain threshold of lumbar latent trigger points: an experimental study

Cervical Myofascial Pain Is Associated with an Imbalance of Masticatory Muscle Activity

This study aimed to assess the relationship between the occurrence of cervical myofascial pain with active myofascial trigger points (MTrPs) within the upper trapezius muscle and the electromyographic asymmetry index (AsI) of masticatory muscles: temporalis anterior (TA), superficial part of the masseter muscle (MM), and anterior belly of the digastric muscle (DA). The study group comprised 100 subjects (80 women and 20 men) aged 18 to 30 years (mean 23 ± 2.6 years) reporting pain in the neck muscles, diagnosed with myofascial pain with active MTrPs only within the upper trapezius muscle. The control group comprised 60 healthy, pain-free subjects (42 women and 18 men) aged 20 to 30 years (mean 22.8 ± 2.6 years) without MTrPs in the upper trapezius muscle. The palpation measurement, based on the diagnostic criteria of Travell and Simons, was used to diagnose active MTrPs. The masticatory muscle activity was recorded using an 8-channel device for surface electromyography—BioEMG III^TM. Significant differences in electromyographic patterns between the group with MTrPs in the right side of upper trapezius muscle and the control group were observed within resting activity for the AsI TA (MTrPs: 8.64 vs. controls: −3.22; p = 0.001) and AsI MM (MTrPs: 7.05 vs. controls: −2.09; p = 0.018). Controls presented different electromyographic patterns during maximum voluntary clenching with cotton rolls between teeth within masseter muscle compared to the MTrPs group (MTrPs: 9.27 vs. controls: −0.43 vs. p = 0.041). Participants with MTrPs in the left side of upper trapezius muscle presented predomination of left-sided electromyographic patterns at rest within temporalis anterior in comparison to controls (MTrPs: −19.22 vs. controls: −3.22; p = 0.001). MTrPs within the trapezius muscle may be related to asymmetry within the masticatory muscle activity, suggesting that the presence of myofascial pain within the cervical muscles plays a role in the imbalance of the stomatognathic system. A unilateral active MTrPs within the trapezius muscle may increase the sEMG activity on the same side of the temporalis anterior and masseter muscles.

The effects of dry needling and radial extracorporeal shockwave therapy on latent trigger point sensitivity in the quadriceps: A randomised control pilot study

OBJECTIVES

Latent myofascial trigger points (TrP) can alter joint kinematics, reduce strength and alter activation patterns, affecting athletic performance. TrP sensitivity can be measured with the pressure pain threshold (PPT). Dry needling (DN) has been used to treat latent TrPs, but may cause post-needling soreness. Radial extracorporeal shockwave therapy (rESWT) could be used as an alternative to DN during heavy training or competition.

METHODS

After baseline measures, 21 recreational athletes were split into three groups: DN, rESWT or control group, and were treated for three sessions in one week. Follow-up outcome sessions were conducted two to four and seven days after the last treatment. TrP sensitivity was measured using the PPT.

RESULTS

There was a groupXtime interaction for the PPT (p < 0.05). After a decrease in PPT during treating, there was a significant increase (p < 0.05) in PPT for the DN group (12.92%). The rESWT group also significantly (p < 0.05) increased (13.26%), but did not show any post-treatment soreness during the treatment phase. There was no difference in the PPT in the control group during any session.

CONCLUSION

DN is effective for increasing PPT of latent TrPs, but can be associated with post-treatment soreness. rESWT is as effective, but without the post-treatment soreness. Future studies should include treating multiple TrPs in the lower kinetic chain as well as measuring muscle activation and joint function. Furthermore, consideration for the current training load and up-coming competition is needed. Optimum timing and longer follow-up periods of such interventions should be explored.

LEVEL OF EVIDENCE

2b.

SUMMARY

Treating latent TrPs in the lower kinetic chain may improve muscle activation. Unlike DN, rESWT does not cause post- treatment soreness. Consideration of training load and up-coming competition is needed to deliver the optimum treatment strategy for athletes with latent TrPs.