Fascial or Muscle Stretching? A Narrative Review

Myofascial junction: Emerging insights into the connection between deep/muscular fascia and muscle

Muscles and fasciae are mutually connected and are influenced by force transmission. However, the anatomical connectivity and histological features of these structures remain unclear. The aim of this study was to assess the evidence for connection between muscles and deep/muscular fasciae. We assessed this relationship in different topographical regions of human cadavers and in mice. The results showed that myofascial junctions (MFJ) were made up of collagen I immune-positive structures occupying an average area of 5.11 ± 0.81 μm2, distributed in discrete regions at the interface between muscle and fascia with an average density of 9.7 ± 2.51 MFJ/mm and an average inclination angle of 35.25 ± 1.52°. These specialized structures also showed collagen III and HA immunopositivity and the presence of elastic fibers. The human myofascial junction can be visualized, opening emerging insights into the connection between deep/muscular fascia and muscle.

Do the fasciae of the soleus have a role in plantar fasciitis?

Plantar fasciitis is a chronic, self-limiting, and painful disabling condition affecting the inferomedial aspect of the heel, usually extending toward the metatarsophalangeal joints. There is compelling evidence for a strong correlation between Achilles tendon (AT) loading and plantar aponeurosis (PA) tension. In line with this, tightness of the AT is found in almost 80% of patients affected by plantar fasciitis. A positive correlation has also been reported between gastrocnemius-soleus tightness and heel pain severity in this condition. Despite its high prevalence, the exact etiology and pathological mechanisms underlying plantar heel pain remain unclear. Therefore, the aim of the present paper is to discuss the anatomical and biomechanical substrates of plantar fasciitis with special emphasis on the emerging, though largely neglected, fascial system. In particular, the relationship between the fascia, triceps surae muscle, AT, and PA will be analyzed. We then proceed to discuss how structural and biomechanical alterations of the muscle-tendon-fascia complex due to muscle overuse or injury can create the conditions for the onset of PA pathology. A deeper knowledge of the possible molecular mechanisms underpinning changes in the mechanical properties of the fascial system in response to altered loading and/or muscle contraction could help healthcare professionals and clinicians refine nonoperative treatment strategies and rehabilitation protocols for plantar fasciitis.

The Effect of Active Release Technique on Hamstring Extensibility: A Critically Appraised Topic

CLINICAL SCENARIO

Hamstring extensibility plays a significant role in maintaining postural alignment essential for a functional musculoskeletal system. When hamstring extensibility is lacking, individuals are placed at a higher risk for developing various lumbar spine, pelvis, knee, and foot dysfunctions. Limited hamstring extensibility is common, occurring in as much as 40% of college students and 86% of the adult population. Therefore, it is essential to maintain hamstring extensibility, which can be aided by understanding intervention effectiveness for improving flexibility.

PURPOSE

To critically appraise the literature on the effectiveness of Active Release Technique (ART) for the treatment of hamstring extensibility deficits.

CLINICAL QUESTION

What is the effect of ART in a healthy population with or without hamstring extensibility deficits?

SUMMARY OF KEY FINDINGS

Three studies were included for critical appraisal. Two studies concluded a single treatment session of ART that individuals possessing limited straight leg raise range of motion experienced improved active knee extension, popliteal angle, and sit-and-reach test measures. In the third study, a single session of ART was effective at improving hamstring extensibility in males without hamstring extensibility dysfunction.

CLINICAL BOTTOM LINE

Based on the current level 1 and level 3 evidence, ART may be an effective treatment to produce acute increases in hamstring extensibility. Future research is still needed.

STRENGTH OF RECOMMENDATION

Level B evidence exists to support the use of ART to improve hamstring extensibility in the healthy population.

Stretch tolerance and elastic passive reaction of the quadriceps femoris seem to depend more on the fascia profundis taut surfaces than on the underlying stretched muscle

The rectus femoris and its covering, the fascia lata (i.e., fascia profundis), are two anatomical structures involved in anterior thigh stretching. This study aimed to identify the role of strain changes in the fascia lata in limiting stretch tolerance. The reaction force intensity of 11 men and 5 women was assessed during passive stretching of the anterior thigh at 130, 110, 90, and 70° of knee flexion. Recent data suggest that the fascia lata strain field is modified with knee flexion. Therefore, the relationship between knee flexion angle and stretch tolerance was assessed. We found that the reaction force of the anterior thigh increased almost linearly with the degree of knee extension between 130° and 70°. The fascia lata stretched surface proprioceptive information seems responsible for stretch tolerance. Fascia profundis strain field must be considered during stretching experiments.

Hearing and Seeing Nerve/Tendon Snapping: A Systematic Review on Dynamic Ultrasound Examination

Nerve/tendon snapping can occur due to their sudden displacement during the movement of an adjacent joint, and the clinical condition can really be painful. It can actually be challenging to determine the specific anatomic structure causing the snapping in various body regions. In this sense, ultrasound examination, with all its advantages (especially providing dynamic imaging), appears to be quite promising. To date, there are no comprehensive reviews reporting on the use of dynamic ultrasound examination in the diagnosis of nerve/tendon snapping. Accordingly, this article aims to provide a substantial discussion as to how US examination would contribute to 'seeing' and 'hearing' these pathologies' different maneuvers/movements.

Crural and Plantar Fasciae Changes in Chronic Charcot Diabetic Foot: A Cross-Sectional Ultrasound Imaging Study-An Evidence of Fascial Continuity

Crural fascia (CF) and plantar fascia (PF) are biomechanically crucial in the gait and in the proprioception, particularly in the propulsion phase of the foot during the gait cycle and in the dissipation of forces during weight-bearing activities. Recent studies have revealed an association between increases in PF thickness and diabetes. The purpose of this study was to measure and compare by ultrasound (US) imaging the thickness of the CF and PF at different regions/levels in chronic Charcot diabetic foot patients (group 1) and in healthy volunteers (group 2). A cross-sectional study was performed using US imaging to measure the CF with Pirri et al.'s protocol and PF with a new protocol in a sample of 31 subjects (15 patients and 16 healthy participants). The findings for CF and PF revealed statistically significant differences in the poster region of CF (Post 1: group 1 vs. group 2: p = 0.03; Post 2: group 1 vs. group 2: p = 0.03) and in PF at two different levels (PF level 1: group 1 vs. group 2: p < 0.0001; PF level 2: group 1 vs. group 2: p < 0.0001). These findings suggest that chronic Charcot diabetic foot patients have CF and PF thicker compared to healthy volunteers. The US examination suggests that fascial thicknesses behavior in these patients points out altered fascial remodeling due to diabetes pathology and biomechanical changes.

Acute effects of foam roller or stick massage on indirect markers from exercise-induced muscle damage in healthy individuals: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis examined the effects of foam roller or stick massage performed after exercise-induced muscle damage protocols on indirect markers of muscle damage compared to a non-intervention control group in healthy individuals.

METHODS

PubMed, Biblioteca Virtual em Saúde, Scopus, Google Scholar, and Cochrane Library database were searched in August 2, 2020, with last update on February 21, 2021. Were included clinical trials involving healthy adult individuals who received foam roller/stick massage versus a non-intervention group and evaluated indirect markers of muscle damage. Risk of bias was assessed by the Cochrane Risk of Bias tools. Standardized mean differences with 95% confidence intervals were used to measure the foam roller/stick massage effect on muscle soreness.

RESULTS

The five included studies investigated 151 participants (136 men). Overall, the studies presented a moderate/high risk of bias. A between-groups meta-analysis showed no significant difference between massage and non-intervention control groups on muscle soreness immediately after (0.26 [95%CI: 0.14; 0.65], p = 0.20), 24 h (-0.64 [95%CI: 1.34; 0.07], p = 0.08), 48 h (-0.35 [95%CI: 0.85; 0.15], p = 0.17), 72 h (-0.40 [95%CI: 0.92; 0.12], p = 0.13), and 96 h (0.05 [95%CI: 0.40; 0.50], p = 0.82) after an exercise-induced muscle damage protocol. Moreover, the qualitative synthesis showed that foam roller or stick massage had no significant effect on range of motion, muscle swelling, and maximal voluntary isometric contraction recovery.

CONCLUSION

In conclusion, the current literature appears to not support the advantage of foam roller or stick massage to improve recovery of muscle damage indirect markers (muscle soreness, range of motion, muscle swelling, and maximal voluntary isometric contraction) compared to a non-intervention control group in healthy individuals. Furthermore, due to the heterogeneity of the methodological designs among the included studies, making it difficult to compare the results. In addition, there are not enough high-quality and well-designed studies on foam roller or stick massage to draw any definite conclusions.

REVIEW PROTOCOL NUMBER

The study was pre-registered in the International Prospective Register of Systematic Review (PROSPERO) on August 2, 2020, with last update on February 21, 2021. Protocol number: CRD2017058559.

Single-cell RNA-seq reveals cellular heterogeneity from deep fascia in patients with acute compartment syndrome

Introduction

High stress in the compartment surrounded by the deep fascia can cause acute compartment syndrome (ACS) that may result in necrosis of the limbs. The study aims to investigate the cellular heterogeneity of the deep fascia in ACS patients by single-cell RNA sequencing (scRNA-seq).

Methods

We collected deep fascia samples from patients with ACS (high-stress group, HG, n=3) and patients receiving thigh amputation due to osteosarcoma (normal-stress group, NG, n=3). We utilized ultrasound and scanning electron microscopy to observe the morphologic change of the deep fascia, used multiplex staining and multispectral imaging to explore immune cell infiltration, and applied scRNA-seq to investigate the cellular heterogeneity of the deep fascia and to identify differentially expressed genes.

Results

Notably, we identified GZMK⁺interferon-act CD4 central memory T cells as a specific high-stress compartment subcluster expressing interferon-related genes. Additionally, the changes in the proportions of inflammation-related subclusters, such as the increased proportion of M2 macrophages and decreased proportion of M1 macrophages, may play crucial roles in the balance of pro-inflammatory and anti-inflammatory in the development of ACS. Furthermore, we found that heat shock protein genes were highly expressed but metal ion-related genes (S100 family and metallothionein family) were down-regulated in various subpopulations under high stress.

Conclusions

We identified a high stress-specific subcluster and variations in immune cells and fibroblast subclusters, as well as their differentially expressed genes, in ACS patients. Our findings reveal the functions of the deep fascia in the pathophysiology of ACS, providing new approaches for its treatment and prevention.

The Effects of Aging on the Intramuscular Connective Tissue

The intramuscular connective tissue plays a critical role in maintaining the structural integrity of the muscle and in providing mechanical support. The current study investigates age-related changes that may contribute to passive stiffness and functional impairment of skeletal muscles. Variations in the extracellular matrix in human quadriceps femoris muscles in 10 young men, 12 elderly males and 16 elderly females, and in the hindlimb muscles of 6 week old, 8 month old and 2 year old C57BL/6J male mice, were evaluated. Picrosirius red, Alcian blue and Weigert Van Gieson stainings were performed to evaluate collagen, glycosamynoglycans and elastic fibers. Immunohistochemistry analyses were carried out to assess collagen I, collagen III and hyaluronan. The percentage area of collagen was significantly higher with aging (p < 0.01 in humans, p < 0.001 in mice), mainly due to an increase in collagen I, with no differences in collagen III (p > 0.05). The percentage area of elastic fibers in the perimysium was significantly lower (p < 0.01) in elderly men, together with a significant decrease in hyaluronan content both in humans and in mice. No significant differences were detected according to gender. The accumulation of collagen I and the lower levels of hyaluronan and elastic fibers with aging could cause a stiffening of the muscles and a reduction of their adaptability.

Modelling intra-muscular contraction dynamics using in silico to in vivo domain translation

BACKGROUND

Advances in sports medicine, rehabilitation applications and diagnostics of neuromuscular disorders are based on the analysis of skeletal muscle contractions. Recently, medical imaging techniques have transformed the study of muscle contractions, by allowing identification of individual motor units' activity, within the whole studied muscle. However, appropriate image-based simulation models, which would assist the continued development of these new imaging methods are missing. This is mainly due to a lack of models that describe the complex interaction between tissues within a muscle and its surroundings, e.g., muscle fibres, fascia, vasculature, bone, skin, and subcutaneous fat. Herein, we propose a new approach to overcome this limitation.

METHODS

In this work, we propose to use deep learning to model the authentic intra-muscular skeletal muscle contraction pattern using domain-to-domain translation between in silico (simulated) and in vivo (experimental) image sequences of skeletal muscle contraction dynamics. For this purpose, the 3D cycle generative adversarial network (cycleGAN) models were evaluated on several hyperparameter settings and modifications. The results show that there were large differences between the spatial features of in silico and in vivo data, and that a model could be trained to generate authentic spatio-temporal features similar to those obtained from in vivo experimental data. In addition, we used difference maps between input and output of the trained model generator to study the translated characteristics of in vivo data.

RESULTS

This work provides a model to generate authentic intra-muscular skeletal muscle contraction dynamics that could be used to gain further and much needed physiological and pathological insights and assess and overcome limitations within the newly developed research field of neuromuscular imaging.

Vibrating Exercise Equipment in Middle-Age and Older Women with Chronic Low Back Pain and Effects on Bioelectrical Activity, Range of Motion and Pain Intensity: A Randomized, Single-Blinded Sham Intervention Study

Simple Summary

Physical activity is often recommended as part of the management of chronic low back pain, which is one of the most common musculoskeletal disorders. Vibrating exercise equipment is used despite little scientific evidence to support its effectiveness in the prevention and treatment of musculoskeletal problems. The aim of this study was to evaluate the efficiency of using vibrating exercise equipment in women with chronic low back pain. Here, 92 women aged 49–80 years were assigned to one of two groups: the experimental and the control group. The intervention consisted of aerobic exercises with specific handheld equipment. Both groups performed physical activity twice weekly for 10 weeks. The erector spinae muscles’ bioelectrical activity, the lumbar range of motion and pain intensity were measured in all participants at baseline and after 10 weeks. Compared with baseline measures, there was a significant decrease in the bioelectrical activity of the erector spinae muscles during flexion movement, rest at maximum flexion, extension movement and rest in a prone position; an increase in the lumbar range of motion and a decrease in pain intensity following a program of physical activity with vibrating exercise equipment. No significant changes were found in intergroup comparisons; however, physical activity with vibrating exercise equipment could be a prospective strategy for increasing lumbar range of motion and decreasing pain and erector spinae muscle activity in people with chronic low back pain.

Abstract

Background: Chronic low back pain (CLBP) is one of the most common musculoskeletal disorders. Physical activity (PA) is often recommended as part of the management of CLBP, but to date, no one particular exercise has been shown to be superior. Vibrating exercise equipment (VEE) is widely available and used despite little scientific evidence to support its effectiveness in the prevention and treatment of musculoskeletal problems. The aim of this study was to evaluate the efficiency of using VEE compared with sham-VEE in women with CLBP. Methods: A randomized (1:1 randomization scheme) single-blinded sham-controlled intervention study was conducted. Through simple randomization, 92 women aged 49–80 years were assigned to one of two groups: VEE (the experimental group) and sham-VEE (the control group). The VEE and sham-VEE intervention consisted of aerobic exercises with specific handheld equipment. Both groups performed physical activity twice weekly for 10 weeks. The erector spinae muscles’ bioelectrical activity (using an eight-channel electromyograph MyoSystem 1400L), lumbar range of motion (Schober’s test) and pain intensity (visual analog scale) were measured in all participants at baseline and after 10 weeks. Results: There was a significant decrease in the bioelectrical activity of the erector spinae muscles during flexion movement (left: Me = 18.2 before; Me = 14.1 after; p = 0.045; right: Me = 15.4 before; Me = 12.6 after; p = 0.010), rest at maximum flexion (left: Me = 18.1 before; Me = 12.5 after; p = 0.038), extension movement (right: Me = 21.8 before; Me = 20.2 after; p = 0.031) and rest in a prone position (right: Me = 3.5 before; Me = 3.2 after; 0.049); an increase in lumbar range of motion (Me = 17.0 before; Me = 18.0 after; p = 0.0017) and a decrease in pain intensity (Me = 4.0 before; Me = 1.0 after; p = 0.001) following a program of PA in the VEE group. Conclusions: No significant changes were found in intergroup comparisons. The beneficial changes regarding decreased subjective pain sensation in the VEE and sham-VEE groups may be due to participation in systematic physical activity. However, PA with vibrating exercise equipment could be a prospective strategy for increasing lumbar range of motion and for decreasing pain and erector spinae muscle activity in people with CLBP.

Fascia Mobility, Proprioception, and Myofascial Pain

The network of fasciae is an important part of the musculoskeletal system that is often overlooked. Fascia mobility, especially along shear planes separating muscles, is critical for musculoskeletal function and may play an important, but little studied, role in proprioception. Fasciae, especially the deep epimysium and aponeuroses, have recently been recognized as highly innervated with small diameter fibers that can transmit nociceptive signals, especially in the presence of inflammation. Patients with connective tissue hyper- and hypo-mobility disorders suffer in large number from musculoskeletal pain, and many have abnormal proprioception. The relationships among fascia mobility, proprioception, and myofascial pain are largely unstudied, but a better understanding of these areas could result in improved care for many patients with musculoskeletal pain.