Myofascial trigger points alter the modular control during the execution of a reaching task: a pilot study

Abstract

Myofascial trigger points (TP) constitute a conundrum in research and clinical practice as their etiopathogenesis is debated. Several studies investigating one or few muscles have shown that both active and latent TP causes an increased muscle activity, however the influence of TP on modular motor control during a reaching task is still unclear. Electromyographic signals, recorded from the muscles of the shoulder girdle and upper arm during a reaching task, were decomposed with Non-Negative Matrix Factorization algorithm. The extracted matrices of motor modules and activation signals were used to label the muscles condition as dominant or non-dominant. The presence of latent and active TP was detected in each muscle with manual examination. Despite a similar muscle activity was observed, we found that muscles with active TP had increased weighting coefficients when labeled in the dominant condition. No influences were found when muscles were in the non-dominant condition. These findings suggest that TP altered the motor control without co-contraction patterns. As a preliminary evidence, the present results suggest that the increased weighting coefficients in presence of TPs are associated with an alteration of the modular motor control without affecting the dimensionality of motor modules for each individual and reciprocal inhibition.

Effects of trigger point dry needling on lateral epicondylalgia of musculoskeletal origin: a systematic review and meta-analysis

“…Our results agree with a previous meta-analysis concluding that low evidence supports an effect of dry needling for improving force production in patients with lateral epicondylalgia. 37 Some evidence supports that muscle trigger points produce muscular fatigability and changes in motor output 38,39 explaining the observed changes in strenght. It is possible that combining dry needling with exercise could lead to better outcomes in this musculoskeletal pain condition.…”

No Evidence of Short-Term Changes in Muscle Activity Elicited by Dry Needling in Chronic Unilateral Shoulder Pain Patients

“…In clinical settings, shoulder impingement syndrome patients has also shown a decrease in the infraspinatus muscle activity during shoulder flexion in the scapular plane and external rotation in comparison with healthy subjects 37,67 . One common characteristic of these conditions is that they present active MTrP, and their presence can be associated with alteration of motor synergies, acceleration of muscle fatigability, and increased activity in the affected and related musculature 25,64,68,69 …”

“…37,67 One common characteristic of these conditions is that they present active MTrP, and their presence can be associated with alteration of motor synergies, acceleration of muscle fatigability, and increased activity in the affected and related musculature. 25,64,68,69 In this study, it was hypothesized that pain relief may produce a change in the activity and coordination of the muscle fibers during shoulder flexion in chronic USP patients. This response has been found for manual therapies combined with exercises in low back pain patients.…”

Modular reorganization of gait in chronic but not in artificial knee joint constraint

“…In addition, the chronic group experienced pain during walking (Table 1). Joint and muscle pain is also known to affect the neural control of individual muscles (92), and how much a muscle is involved in a motor module (93). Second, the long exposure to the joint constraint may also result in secondary changes in the central nervous system (e.g., muscle hyperreflexia, altered somatosensory feedback, and intersegmental facilitative pathways at spinal level) (27,28,94), contributing to abnormal timing of leg extensors during the stance phase (94).…”