Cyclic compressive loading facilitates recovery after eccentric exercise

Role of macrophages during skeletal muscle regeneration and hypertrophy-Implications for immunomodulatory strategies

Skeletal muscle is a plastic tissue that regenerates ad integrum after injury and adapts to raise mechanical loading/contractile activity by increasing its mass and/or myofiber size, a phenomenon commonly refers to as skeletal muscle hypertrophy. Both muscle regeneration and hypertrophy rely on the interactions between muscle stem cells and their neighborhood, which include inflammatory cells, and particularly macrophages. This review first summarizes the role of macrophages in muscle regeneration in various animal models of injury and in response to exercise-induced muscle damage in humans. Then, the potential contribution of macrophages to skeletal muscle hypertrophy is discussed on the basis of both animal and human experiments. We also present a brief comparative analysis of the role of macrophages during muscle regeneration versus hypertrophy. Finally, we summarize the current knowledge on the impact of different immunomodulatory strategies, such as heat therapy, cooling, massage, nonsteroidal anti-inflammatory drugs and resolvins, on skeletal muscle regeneration and their potential impact on muscle hypertrophy.

Effects of Distinct Force Magnitude of Spinal Manipulative Therapy on Blood Biomarkers of Inflammation: A Proof of Principle Study in Healthy Young Adults

OBJECTIVES

The purpose of this preliminary study was to determine the influence of thoracic spinal manipulation therapy (SMT) of different force magnitudes on blood biomarkers of inflammation in healthy adults.

METHODS

Nineteen healthy young adults (10 female, age: 25.6 ± 1.2 years) were randomized into the following 3 groups: (1) control (preload only), (2) single thoracic SMT with a total peak force of 400N, and (3) single thoracic SMT with a total peak force of 800N. SMT was performed by an experienced chiropractor, and a force-plate embedded treatment table (Force Sensing Table Technology) was used to determine the SMT force magnitudes applied. Blood samples were collected at pre intervention (baseline), immediately post intervention, and 20 minutes post intervention. A laboratory panel of 14 different inflammatory biomarkers (pro, anti, dual role, chemokine, and growth factor) was assessed by multiplex array. Change scores from baseline of each biomarker was used for statistical analysis. Two-way repeated-measures analysis of variance was used to investigate the interaction and main effects of intervention and time on cytokines, followed by Tukey's multiple comparison test (P ≤ .05).

RESULTS

A between-group (800N vs 400N) difference was observed on interferon-gamma, interleukin (IL)-5, and IL-6, while a within-group difference (800N: immediately vs 20 minutes post-intervention) was observed on IL-6 only.

CONCLUSION

In this study, we measured short-term changes in plasma cytokines in healthy young adults and found that select plasma pro-inflammatory and dual-role cytokines were elevated by higher compared to lower SMT force. Our findings aid to advance our understanding of the potential relationship between SMT force magnitude and blood cytokines and provide a healthy baseline group with which to compare similar studies in clinical populations in the future.

Manual Therapy Facilitates Homeostatic Adaptation to Bone Microstructural Declines Induced by a Rat Model of Repetitive Forceful Task

The effectiveness of manual therapy in reducing the catabolic effects of performing repetitive intensive force tasks on bones has not been reported. We examined if manual therapy could reduce radial bone microstructural declines in adult female Sprague–Dawley rats performing a 12-week high-repetition and high-force task, with or without simultaneous manual therapy to forelimbs. Additional rats were provided 6 weeks of rest after task cessation, with or without manual therapy. The control rats were untreated or received manual therapy for 12 weeks. The untreated TASK rats showed increased catabolic indices in the radius (decreased trabecular bone volume and numbers, increased osteoclasts in these trabeculae, and mid-diaphyseal cortical bone thinning) and increased serum CTX-1, TNF-α, and muscle macrophages. In contrast, the TASK rats receiving manual therapy showed increased radial bone anabolism (increased trabecular bone volume and osteoblast numbers, decreased osteoclast numbers, and increased mid-diaphyseal total area and periosteal perimeter) and increased serum TNF-α and muscle macrophages. Rest, with or without manual therapy, improved the trabecular thickness and mid-diaphyseal cortical bone attributes but not the mineral density. Thus, preventive manual therapy reduced the net radial bone catabolism by increasing osteogenesis, while rest, with or without manual therapy, was less effective.

Mechanotherapy Reprograms Aged Muscle Stromal Cells to Remodel the Extracellular Matrix during Recovery from Disuse

Aging is accompanied by reduced remodeling of skeletal muscle extracellular matrix (ECM), which is exacerbated during recovery following periods of disuse atrophy. Mechanotherapy has been shown to promote ECM remodeling through immunomodulation in adult muscle recovery, but not during the aged recovery from disuse. In order to determine if mechanotherapy promotes ECM remodeling in aged muscle, we performed single cell RNA sequencing (scRNA-seq) of all mononucleated cells in adult and aged rat gastrocnemius muscle recovering from disuse, with (REM) and without mechanotherapy (RE). We show that fibroadipogenic progenitor cells (FAPs) in aged RE muscle are highly enriched in chemotaxis genes (Csf1), but absent in ECM remodeling genes compared to adult RE muscle (Col1a1). Receptor-ligand (RL) network analysis of all mononucleated cell populations in aged RE muscle identified chemotaxis-enriched gene expression in numerous stromal cell populations (FAPs, endothelial cells, pericytes), despite reduced enrichment of genes related to phagocytic activity in myeloid cell populations (macrophages, monocytes, antigen presenting cells). Following mechanotherapy, aged REM mononuclear cell gene expression resembled adult RE muscle as evidenced by RL network analyses and KEGG pathway activity scoring. To validate our transcriptional findings, ECM turnover was measured in an independent cohort of animals using in vivo isotope tracing of intramuscular collagen and histological scoring of the ECM, which confirmed mechanotherapy-mediated ECM remodeling in aged RE muscle. Our results highlight age-related cellular mechanisms underpinning the impairment to complete recovery from disuse, and also promote mechanotherapy as an intervention to enhance ECM turnover in aged muscle recovering from disuse.

Manual Therapy Research Methods in Animal Models, Focusing on Soft Tissues

Manual therapies have been practiced for centuries, yet little research has been performed to understand their efficacy and almost no animal research has been performed to inform mechanisms of action. The methods of manual therapy practice are quite varied and present a challenge for scientists to model the treatments and perform research using rodents. In this perspective we present a descriptive analysis of the complexity of the treatments, highlighting the role of tissue mechanics and physics. With these complexities in mind, we compare using manual therapy as clinically practiced, to attempts to develop machinery to model or mimic manual therapy. We propose that because of the complexities of manual therapy as practiced, having therapists perform the treatments on research animals just as they would on humans is the most scientific approach. Our results using this approach have supported its practicality.

Key indicators of repetitive overuse-induced neuromuscular inflammation and fibrosis are prevented by manual therapy in a rat model

BACKGROUND

We examined the effectiveness of a manual therapy consisting of forearm skin rolling, muscle mobilization, and upper extremity traction as a preventive treatment for rats performing an intensive lever-pulling task. We hypothesized that this treatment would reduce task-induced neuromuscular and tendon inflammation, fibrosis, and sensorimotor declines.

METHODS

Sprague-Dawley rats performed a reaching and lever pulling task for a food reward, 2 h/day, 3 days/week, for 12 weeks, while simultaneously receiving the manual therapy treatment 3 times per week for 12 weeks to either the task-involved upper extremities (TASK-Tx), or the lower extremities as an active control group (TASK-Ac). Results were compared to similarly treated control rats (C-Tx and C-Ac).

RESULTS

Median nerves and forearm flexor muscles and tendons of TASK-Ac rats showed higher numbers of inflammatory CD68+ and fibrogenic CD206+ macrophages, particularly in epineurium, endomysium and epitendons than TASK-Tx rats. CD68+ and CD206+ macrophages numbers in TASK-Tx rats were comparable to the non-task control groups. TASK-Ac rats had more extraneural fibrosis in median nerves, pro-collagen type I levels and immunoexpression in flexor digitorum muscles, and fibrogenic changes in flexor digitorum epitendons, than TASK-Tx rats (which showed comparable responses as control groups). TASK-Ac rats showed cold temperature, lower reflexive grip strength, and task avoidance, responses not seen in TASK-Tx rats (which showed comparable responses as the control groups).

CONCLUSIONS

Manual therapy of forelimbs involved in performing the reaching and grasping task prevented the development of inflammatory and fibrogenic changes in forearm nerves, muscle, and tendons, and sensorimotor declines.

Massage as a Mechanotherapy for Skeletal Muscle

Massage is anecdotally associated with many health benefits, but physiological and clinically relevant mechanisms recently have begun to be investigated in a controlled manner. Herein, we describe research supporting our hypothesis that massage can be used as a mechanotherapy imparting biologically relevant adaptations in skeletal muscle and improving muscle properties.

Application of traditional Chinese therapy in sports medicine

Chinese herbs have been used as dietary supplements to improve exercise performance. However, evidence-based studies for the use of Chinese herbs in sports remain scarce. Traditional Chinese therapy (TCT), a form of traditional Chinese non-pharmacological intervention, has remained in use for thousands of years in sports medicine. TCT is beneficial for sports injuries and in enhancing skill development, and is becoming increasingly popular among athletes, fitness enthusiasts, and individuals who regularly exercise. The therapeutic effects of TCT have been demonstrated by clinical and experimental studies, but using these modalities still is associate with potentially adverse effects. Further well-designed studies are necessary to confirm the efficacy of TCT in sports medicine. This review aims to summarize the application of TCT, discuss the issues surrounding TCT clinical research, and provide suggestions for applying traditional Chinese methods in the field of sports medicine.

Muscle from aged rats is resistant to mechanotherapy during atrophy and reloading

Massage is a viable mechanotherapy to improve protein turnover during disuse atrophy and improve muscle regrowth during recovery from disuse atrophy in adult muscle. Therefore, we investigated whether massage can cause beneficial adaptations in skeletal muscle from aged rats during normal weight-bearing (WB) conditions, hindlimb suspension (HS), or reloading (RE) following HS. Aged (30 months) male Fischer 344/Brown Norway rats were divided into two experiments: (1) WB for 7 days (WB, n = 8), WB with massage (WBM, n = 8), HS for 7 days (HS7, n = 8), or HS with massage (HSM, n = 8), and (2) WB for 14 days (WB14, n = 8), HS for 14 days (HS14, n = 8), reloading (RE, n = 10), or reloading with massage (REM, n = 10) for 7 days following HS. Deuterium oxide (D2O) labeling was used to assess dynamic protein and ribosome turnover in each group and anabolic signaling pathways were assessed. Massage did have an anabolic benefit during RE or WB. In contrast, massage during HS enhanced myofibrillar protein turnover in both the massaged limb and contralateral non-massaged limb compared with HS, but this did not prevent muscle loss. Overall, the data demonstrate that massage is not an effective mechanotherapy for prevention of atrophy during muscle disuse or recovery of muscle mass during reloading in aged rats.

Massage as a mechanotherapy promotes skeletal muscle protein and ribosomal turnover but does not mitigate muscle atrophy during disuse in adult rats

AIM

Interventions that decrease atrophy during disuse are desperately needed to maintain muscle mass. We recently found that massage as a mechanotherapy can improve muscle regrowth following disuse atrophy. Therefore, we aimed to determine if massage has similar anabolic effects when applied during normal weight bearing conditions (WB) or during atrophy induced by hindlimb suspension (HS) in adult rats.

METHODS

Adult (10 months) male Fischer344-Brown Norway rats underwent either hindlimb suspension (HS, n = 8) or normal WB (WB, n = 8) for 7 days. Massage was applied using cyclic compressive loading (CCL) in WB (WBM, n = 9) or HS rats (HSM, n = 9) and included four 30-minute bouts of CCL applied to gastrocnemius muscle every other day.

RESULTS

Massage had no effect on any anabolic parameter measured under WB conditions (WBM). In contrast, massage during HS (HSM) stimulated protein turnover, but did not mitigate muscle atrophy. Atrophy from HS was caused by both lowered protein synthesis and higher degradation. HS and HSM had lowered total RNA compared with WB and this was the result of significantly higher ribosome degradation in HS that was attenuated in HSM, without differences in ribosomal biogenesis. Also, massage increased protein turnover in the non-massaged contralateral limb during HS. Finally, we determined that total RNA degradation primarily dictates loss of muscle ribosomal content during disuse atrophy.

CONCLUSION

We conclude that massage is an effective mechanotherapy to impact protein turnover during muscle disuse in both the massaged and non-massaged contralateral muscle, but it does not attenuate the loss of muscle mass.

Massage Therapy Modulates Inflammatory Mediators Following Sprint Exercise in Healthy Male Athletes

Massage therapy is a common postexercise muscle recovery modality; however, its mechanisms of efficacy are uncertain. We evaluated the effects of massage on systemic inflammatory responses to exercise and postexercise muscle performance and soreness. In this crossover study, nine healthy male athletes completed a high-intensity intermittent sprint protocol, followed by massage therapy or control condition. Inflammatory markers were assessed pre-exercise; postexercise; and at 1, 2, and 24 h postexercise. Muscle performance was measured by squat and drop jump, and muscle soreness on a Likert scale. Significant time effects were observed for monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), drop jump performance, squat jump performance, and soreness. No significant effects for condition were observed. However, compared with control, inflammatory marker concentrations (IL-8, TNFα, and MCP-1) returned to baseline levels earlier following the massage therapy condition (p < 0.05 for all). IL-6 returned to baseline levels earlier following the control versus massage therapy condition (p < 0.05). No differences were observed for performance or soreness variables. MCP-1 area under the curve (AUC) was negatively associated with squat and drop jump performance, while IL-10 AUC was positively associated with drop jump performance (p < 0.05 for all). In conclusion, massage therapy promotes resolution of systemic inflammatory signaling following exercise but does not appear to improve performance or soreness measurements.

Massage increases satellite cell number independent of the age-associated alterations in sarcolemma permeability

Massage is a widely accepted manual therapy used to modulate the inflammatory response of muscle and restore function, but prolonged compression of muscle potentially causes overt injury and damage to muscle fibers. Therefore, a balance exists between the positive effects of massage and the induction of mechanical damage and injury. In addition, skeletal muscle of aged individuals displays increased stiffness, and therefore, the response to massage is likely different compared with young. We hypothesized that the aged skeletal muscle exhibits increased sarcolemmal permeability when subjected to massage compared with young skeletal muscle. Male Brown Norway/F344 rats, 10 and 30 months of age, were each divided into control, non-massaged (n = 8) and massaged (n = 8) groups. The right gastrocnemius muscle received one bout of cyclic compressive loading for 30 min at 4.5 N as a massage-mimetic. Muscles were dissected and frozen 24 h after massage. Alterations in sarcolemma permeability were quantified by measuring the level of intracellular IgG within the muscle fibers. Immunohistochemistry was performed to determine IgG inside fibers and Pax7+ cell number as an indicator of stem cell abundance. Average IgG intensity was not different between control and massaged animals at either age. However, a significant shift to the right of the density histogram indicated that massaged animals had more fibers with higher IgG intensity than control at 10 months. In addition, Pax7+ cell number was significantly elevated in massaged muscles compared with control at both ages. One bout of massage did not induce overt muscle injury, but facilitated membrane permeability, which was associated with an increase in satellite cell number. Data suggest that the load applied here, which was previously shown to induce immunomodulatory changes, does not induce overt muscle injury in young and old muscles but may result in muscle remodeling. Funded by NIH grant AG042699 and AT009268.

Using Massage to Combat Fear-Avoidance and the Pain Tension Cycle

Massage is a common therapeutic modality utilized by clinicians in a variety of settings to help treat injuries, reduce pain, and return function to patients. Massage benefits the patients both psychologically and physiologically, as patients report less pain and anxiety along with better mood and even decreased blood pressure following massage. Additionally, on the cellular level, massage has the ability to modulate the damaging inflammatory process and, in some cases, influence protein synthesis. Although massage has not been linked to a rehabilitation theory to date, this paper will propose how massage may influence fear-avoidance beliefs, or the patient’s inability to cope with pain that then leads to a pain tension cycle. Pain will often result in use avoidance, which creates muscle tension that further exacerbates the pain. Massage can affect the Fear-Avoidance Model because the beneficial effects of massage can break the cycle by either relieving the patient’s pain or eliminating the muscle tension. A modified Fear-Avoidance Model is presented that conceptualizes how pain and fear-avoidance lead to tension and muscle dysfunction. Massage has been incorporated into the model to demonstrate its potential for breaking the pain tension cycle. This model has the potential to be applied in clinical settings and provides an alternate treatment to patients with chronic pain who present with increased levels of fear-avoidance beliefs.

Enhanced skeletal muscle regrowth and remodelling in massaged and contralateral non-massaged hindlimb

KEY POINTS

Muscle fibre cross sectional area is enhanced with massage in the form of cyclic compressive loading during regrowth after atrophy. Massage enhances protein synthesis of the myofibrillar and cytosolic, but not the mitochondrial fraction, in muscle during regrowth. Focal adhesion kinase activation and satellite cell number are elevated in muscles undergoing massage during regrowth. Muscle fibre cross sectional area and protein synthesis of the myofibrillar fraction, but not DNA synthesis, are elevated in muscle of the contralateral non-massaged limb. Massage in the form of cyclic compressive loading is a potential anabolic intervention during muscle regrowth after atrophy.

ABSTRACT

Massage, in the form of cyclic compressive loading (CCL), is associated with multiple health benefits, but its potential anabolic effect on atrophied muscle has not been investigated. We hypothesized that the mechanical activity associated with CCL induces an anabolic effect in skeletal muscle undergoing regrowth after a period of atrophy. Fischer-Brown Norway rats at 10 months of age were hindlimb unloaded for a period of 2 weeks. The rats were then allowed reambulation with CCL applied at a 4.5 N load at 0.5 Hz frequency for 30 min every other day for four bouts during a regrowth period of 8 days. Muscle fibre cross sectional area was enhanced by 18% with massage during regrowth compared to reloading alone, and this was accompanied by elevated myofibrillar and cytosolic protein as well as DNA synthesis. Focal adhesion kinase phosphorylation indicated that CCL increased mechanical stimulation, while a higher number of Pax7+ cells likely explains the elevated DNA synthesis. Surprisingly, the contralateral non-massaged limb exhibited a comparable 17% higher muscle fibre size compared to reloading alone, and myofibrillar protein synthesis, but not DNA synthesis, was also elevated. We conclude that massage in the form of CCL induces an anabolic response in muscles regrowing after an atrophy-inducing event. We suggest that massage can be used as an intervention to aid in the regrowth of muscle lost during immobilization.

Design and Characterization of a Soft Robotic Therapeutic Glove for Rheumatoid Arthritis

The modeling and experimentation of a pneumatic actuation system for the development of a soft robotic therapeutic glove is proposed in this article for the prevention of finger deformities in rheumatoid arthritis (RA) patients. The Rehabilitative Arthritis Glove (RA-Glove) is a soft robotic glove fitted with two internal inflatable actuators for lateral compression and massage of the fingers and their joints. Two mechanical models to predict the indentation and bending characteristics of the inflatable actuators based on their geometrical parameters will be presented and validated with experimental results. Experimental validation shows that the model was within a standard deviation of the experimental mean for input pressure range of 0 to 2 bars. Evaluation of the RA-Glove was also performed on six healthy human subjects. The stress distribution along the fingers of the subjects using the RA-Glove was also shown to be even and specific to the finger sizes. This article demonstrates the modeling of soft pneumatic actuators and highlights the potential of the RA-Glove as a therapeutic device for the prevention of arthritic deformities of the fingers.

The effects of pre-exercise vibration stimulation on the exercise-induced muscle damage

[Purpose] To investigate the effects of pre-induced muscle damage vibration stimulation on the pressure-pain threshold and muscle-fatigue-related metabolites of exercise-induced muscle damage. [Subjects and Methods] Thirty healthy, adult male subjects were randomly assigned to the pre-induced muscle damage vibration stimulation group, post-induced muscle damage vibration stimulation group, or control group (n=10 per group). To investigate the effects of pre-induced muscle damage vibration stimulation, changes in the pressure-pain threshold (lb), creatine kinase level (U/L), and lactate dehydrogenase level (U/L) were measured and analyzed at baseline and at 24 hours, 48 hours, and 72 hours after exercise. [Results] The pressure-pain thresholds and concentrations of creatine kinase and lactate dehydrogenase varied significantly in each group and during each measurement period. There were interactions between the measurement periods and groups, and results of the post-hoc test showed that the pre-induced muscle damage vibration stimulation group had the highest efficacy among the groups. [Conclusion] Pre-induced muscle damage vibration stimulation is more effective than post-induced muscle damage vibration stimulation for preventing muscle damage.

An Old Problem: Aging and Skeletal-Muscle-Strain Injury

Clinical Scenario: Even though chronological aging is an inevitable phenomenological consequence occurring in every living organism, it is biological aging that may be the most significant factor challenging our quality of life. Development of functional limitations, resulting from improper maintenance and restoration of various organ systems, ultimately leads to reduced health and independence. Skeletal muscle is an organ system that, when challenged, is often injured in response to varying stimuli. Overt muscle-strain injury can be traumatic, clinically diagnosable, properly managed, and a remarkably common event, yet our contemporary understanding of how age and environmental stressors affect the initial and subsequent induction of injury and how the biological processes resulting from this event are modifiable and, eventually, lead to functional restoration and healing of skeletal muscle and adjacent tissues is presently unclear. Even though the secondary injury response to and recovery from "contraction-induced" skeletal-muscle injury are impaired with aging, there is no scientific consensus as to the exact mechanism responsible for this event. Given the multitude of investigative approaches, particular consideration given to the appropriateness of the muscle-injury model, or research paradigm, is critical so that outcomes may be physiologically relevant and translational. In this case, methods implementing stretch-shortening contractions, the most common form of muscle movements used by all mammals during physical movement, work, and activity, are highlighted.

CLINICAL RELEVANCE

Understanding the fundamental evidence regarding how aging influences the responsivity of skeletal muscle to strain injury is vital for informing how clinicians approach and implement preventive strategies, as well as therapeutic interventions. From a practical perspective, maintaining or improving the overall health and tissue quality of skeletal muscle as one ages will positively affect skeletal muscle's safety threshold and responsivity, which may reduce incidence of injury, improve recovery time, and lessen overall fiscal burdens.

Short-term effects of vacuum massage on epidermal and dermal thickness and density in burn scars: an experimental study

BACKGROUND

Vacuum massage is a non-invasive mechanical massage technique invented to treat burns and scars. To date, no effects of vacuum massage on thickness and density of human scar tissue have been reported. The process in which external stimuli are converted into biochemical responses in the cell is known as mechanotransduction. In the skin endothelial cells, fibroblasts and myofibroblasts embedded in the extracellular matrix (ECM) sense mechanical stimuli (created by vacuum massage) and may promote intracellular processes leading to matrix remodelling. Since mechanotransduction could be a plausible working mechanism for vacuum massage as an anti-scarring therapy, this study aims to investigate the short-term effects of vacuum massage on thickness and density of epidermis and dermis in burn scars in order to find proof of ECM remodelling.

METHODS

A one group experimental study was performed. Patients with burn scars on upper extremities, lower extremities, and trunk were recruited for participation in this study. The DUB®cutis 22 MHz ultrasound scanner was used to assess thickness and density of the epidermal and dermal skin layers. After baseline measurements, vacuum massage was performed according to a pre-defined protocol. Measurements were carried out at 5 min, 30 min, 1 h, and 2 h post-intervention.

RESULTS

Thirteen scar sites from 9 different patients were investigated. In 8 out of the 13 scar sites, a disruption of the epidermis was noticed after the vacuum massage. Five minutes after the intervention, epidermal density decreased statistically significantly (p = .022) and dermal thickness increased (p = .018). Both changes lasted for more than 1 h, but after 2 h, the changes were no longer statistically significant. Dermal density decreased significantly (p = .048) immediately after the intervention, and this decrease was still present after 2 h (p = .011).

CONCLUSIONS

Preliminary results show that the disruption of the epidermis may indicate that vacuum massage could be able to actually breach the skin barrier. The statistically significant changes in the dermal layers could suggest an increased ECM production after vacuum massage.

Comparing the Effects of Rest and Massage on Return to Homeostasis Following Submaximal Aerobic Exercise: a Case Study

INTRODUCTION

Postexercise massage can be used to help promote recovery from exercise on the cellular level, as well as systemically by increasing parasympathetic activity. No studies to date have been done to assess the effects of massage on postexercise metabolic changes, including excess postexercise oxygen consumption (EPOC). The purpose of this study was to compare the effects of massage recovery and resting recovery on a subject's heart rate variability and selected metabolic effects following a submaximal treadmill exercise session.

METHODS

One healthy 24-year-old female subject performed 30 minutes of submaximal treadmill exercise prior to resting or massage recovery sessions. Metabolic data were collected throughout the exercise sessions and at three 10 minute intervals postexercise. Heart rate variability was evaluated for 10 minutes after each of two 30-minute recovery sessions, either resting or massage.

RESULTS

Heart rate returned to below resting levels (73 bpm) with 30 and 60 minutes of massage recovery (72 bpm and 63 bpm, respectively) compared to 30 and 60 minutes of resting recovery (77 bpm and 74 bpm, respectively). Heart rate variability data showed a more immediate shift to the parasympathetic state following 30 minutes of massage (1.152 LF/HF ratio) versus the 30-minute resting recovery (6.91 LF/HF ratio). It took 60 minutes of resting recovery to reach similar heart rate variability levels (1.216 LF/HF) found after 30 minutes of massage. Ventilations after 30 minutes of massage recovery averaged 7.1 bpm compared to 17.9 bpm after 30 minutes of resting recovery.

CONCLUSIONS

No differences in EPOC were observed through either the resting or massage recovery based on the metabolic data collected. Massage was used to help the subject shift into parasympathetic activity more quickly than rest alone following a submaximal exercise session.

Effects of Massage on Muscular Strength and Proprioception After Exercise-Induced Muscle Damage

Exercise-induced muscle damage (EIMD), which is commonly associated with eccentric exercise, unaccustomed exercise, and resistance training, may lead to delayed onset muscle soreness, swelling, decreased muscle strength, and range of motion. Many researchers have evaluated various interventions to treat the signs and symptoms of EIMD. However, the effects of massage after EIMD are unclear. Here, we investigated the effect of massage on muscle strength and proprioception after EIMD. All subjects randomly were divided into an EIMD-treated control group (n = 10) and a massage-treated after EIMD experimental group (n = 11). Exercise-induced muscle damage was induced by repeated exercise. Massage treatment was provided by physiotherapist for 15 minutes. It consists of light stroking, milking, friction, and skin rolling. Lactate was evaluated by Lactate Pro analyzer in pre- and postexercise. Surface electromyography (muscle activity) and sonography (muscle thickness) were used to confirm the muscular characteristics. Proprioception was investigated by dual inclinometer. As a result, massage treatment on the gastrocnemius after EIMD increased activation of the medial gastrocnemius during contraction (p ≤ 0.05). In the lateral and medial gastrocnemius, the θs, which is the angle between muscle fibers and superficial aponeurosis, showed a significant change (p ≤ 0.05). However, there are no differences in the θd, which is the angle between muscle fibers and deep aponeurosis. We also found that proprioceptive acuity in the ankle joint was significantly greater in the massage-treated experimental group compared with that in the control group (p ≤ 0.05). These findings suggest that massage of the gastrocnemius after EIMD can improve muscle strength and proprioception by influencing the superficial layer of the gastrocnemius.

Is self myofascial release an effective preexercise and recovery strategy? A literature review

The use of self myofascial release (SMR) via a foam roller or roller massager is becoming increasingly popular both to aid recovery from exercise and prevent injury. Our objective was to review the literature on SMR and its use for preexercise, recovery, or maintenance. PUBMED, EBSCO (MEDLINE), EMBASE, and CINAHL were searched for variations and synonyms of "self myofascial release" and "foam rolling." Data from nine studies were examined, and overall quality varied based on study protocol, muscle group targeted, and outcomes measured. Despite the heterogeneity of these studies, SMR appears to have a positive effect on range of motion and soreness/fatigue following exercise, but further study is needed to define optimal parameters (timing and duration of use) to aid performance and recovery.

Biologic-free mechanically induced muscle regeneration

Severe skeletal muscle injuries are common and can lead to extensive fibrosis, scarring, and loss of function. Clinically, no therapeutic intervention exists that allows for a full functional restoration. As a result, both drug and cellular therapies are being widely investigated for treatment of muscle injury. Because muscle is known to respond to mechanical loading, we investigated instead whether a material system capable of massage-like compressions could promote regeneration. Magnetic actuation of biphasic ferrogel scaffolds implanted at the site of muscle injury resulted in uniform cyclic compressions that led to reduced fibrous capsule formation around the implant, as well as reduced fibrosis and inflammation in the injured muscle. In contrast, no significant effect of ferrogel actuation on muscle vascularization or perfusion was found. Strikingly, ferrogel-driven mechanical compressions led to enhanced muscle regeneration and a ∼threefold increase in maximum contractile force of the treated muscle at 2 wk compared with no-treatment controls. Although this study focuses on the repair of severely injured skeletal muscle, magnetically stimulated bioagent-free ferrogels may find broad utility in the field of regenerative medicine.

Alternative treatments for muscle injury: massage, cryotherapy, and hyperbaric oxygen

Current evidence suggests that popular alternative therapies such as massage, cryotherapy, and hyperbaric oxygen exposure as currently practiced on humans have little effect on recovery from minor muscle damage such as induced by exercise. While further research is still needed, hyperbaric oxygen exposure shows clear promise for potentially being a successful adjunct treatment for enhancing muscle repair and recovery from more severe crush on contusion injury in humans. Cryotherapy or icing, as currently practiced, will not likely be successful in cooling muscle sufficiently to have any significant influence on muscle repair regardless of the degree of injury. However, based on studies in animal models, it may be that if sufficient muscle cooling could be achieved in humans, it could actually delay recovery and increase muscle scarring following significant muscle damage. Conclusions about the effectiveness of massage on influencing muscle recovery from more severe injury cannot yet be made due to a lack of experimental evidence with a more significant muscle damage model.

Manual therapy ameliorates delayed-onset muscle soreness and alters muscle metabolites in rats

Delayed-onset muscle soreness (DOMS) can be induced by lengthening contraction (LC); it can be characterized by tenderness and movement-related pain in the exercised muscle. Manual therapy (MT), including compression of exercised muscles, is widely used as physical rehabilitation to reduce pain and promote functional recovery. Although MT is beneficial for reducing musculoskeletal pain (i.e. DOMS), the physiological mechanisms of MT remain unclear. In the present study, we first developed an animal model of MT in DOMS; LC was applied to the rat gastrocnemius muscle under anesthesia, which induced mechanical hyperalgesia 2–4 days after LC. MT (manual compression) ameliorated mechanical hyperalgesia. Then, we used capillary electrophoresis time-of-flight mass spectroscopy (CE-TOFMS) to investigate early effects of MT on the metabolite profiles of the muscle experiencing DOMS. The rats were divided into the following three groups; (1) normal controls, (2) rats with LC application (LC group), and (3) rats undergoing MT after LC (LC + MT group). According to the CE-TOFMS analysis, a total of 171 metabolites were detected among the three groups, and 19 of these metabolites were significant among the groups. Furthermore, the concentrations of eight metabolites, including branched-chain amino acids, carnitine, and malic acid, were significantly different between the LC + MT and LC groups. The results suggest that MT significantly altered metabolite profiles in DOMS. According to our findings and previous data regarding metabolites in mitochondrial metabolism, the ameliorative effects of MT might be mediated partly through alterations in metabolites associated with mitochondrial respiration.

Transverse forces in skeletal muscle with massage-like loading in a rabbit model

Background

The objective of this study was to quantify the transverse forces in skeletal muscle subjected to constant compressive massage-like loading (MLL) following eccentric exercise (ECC).

Methods

Twenty-eight New Zealand White rabbits were used for this two-part study. For all testing, a customized electromechanical device was utilized to apply a constant compressive force MLL to the tibialis anterior (TA) muscle and the resultant transverse forces were quantified. The device consisted of two stepper motors that were positioned orthogonally to each other and connected to separate sliding tracks. A stainless steel cylindrical massage tip was mounted to a customized two-axis sensor consisting of two strain gauges with which forces along the two axes were measured. First, we determined the effects of tissue loading frequency and compression magnitude on transverse forces in the TA. Following a bout of ECC, sixteen rabbits were randomly assigned to a protocol with MLL frequency of 0.25 Hz or 0.5 Hz at a constant compressive force of 5 N or 10 N. Secondly, we utilized a protocol of 0.5 Hz, 10 N, 15 min MLL that was performed on 4 consecutive days commencing immediately post ECC (n = 6 animals) or 48 hours following ECC (n = 6 animals). Transverse forces were measured during all 4 MLL sessions for the entire 15 min duration for both the immediate and the delayed groups.

Results

Both frequency and magnitude of compressive force due to MLL showed an effect on the magnitude of transverse force (p < 0.05 for each parameter). Furthermore, MLL beginning immediately following ECC produced higher transverse forces than MLL delayed by 48 hours with an average 20% difference between the two MLL groups over the four day protocol. Forces were higher in the middle 5 minutes compared to the first 5 minutes for all MLL bouts in both groups.

Conclusions

Frequency and magnitude of MLL and timing for delivery of MLL following ECC affect resultant transverse force values for exercised muscle. The application of our findings to humans receiving massage following exercise remains unknown at this time.

Effects of immediate vs. delayed massage-like loading on skeletal muscle viscoelastic properties following eccentric exercise

BACKGROUND

This study compared immediate versus delayed massage-like compressive loading on skeletal muscle viscoelastic properties following eccentric exercise.

METHODS

Eighteen rabbits were surgically instrumented with peroneal nerve cuffs for stimulation of the tibialis anterior muscle. Rabbits were randomly assigned to a massage loading protocol applied immediately post exercise (n=6), commencing 48h post exercise (n=6), or exercised no-massage control (n=6). Viscoelastic properties were evaluated in vivo by performing a stress-relaxation test pre- and post-exercise and daily pre- and post-massage for four consecutive days of massage loading. A quasi-linear viscoelastic approach modeled the instantaneous elastic response (AG0), fast (g1(p)) and slow (g2(p)) relaxation coefficients, and the corresponding relaxation time constants τ1 and τ2.

FINDINGS

Exercise increased AG0 in all groups (P<0.05). After adjusting for the three multiple comparisons, recovery of AG0 was not significant in the immediate (P=0.021) or delayed (P=0.048) group compared to the control group following four days of massage. However, within-day (pre- to post-massage) analysis revealed a decrease in AG0 in both massage groups. Following exercise, g1(p) increased and g2(p) and τ1 decreased for all groups (P<0.05). Exercise had no effect on τ2 (P>0.05). After four days of massage, there was no significant recovery of the relaxation parameters for either massage loading group compared to the control group.

INTERPRETATION

Our findings suggest that massage loading following eccentric exercise has a greater effect on reducing muscle stiffness, estimated by AG0, within-day rather than affecting recovery over multiple days. Massage loading also has little effect on the relaxation response.

Investigating the mechanisms of massage efficacy: the role of mechanical immunomodulation

Massage has the potential to attenuate the inflammatory process, facilitate early recovery, and provide pain relief from muscular injuries. In this hypothesis-driven paper, we integrate the concept of mechanotransduction with the application of massage to explore beneficial mechanisms. By altering signaling pathways involved with the inflammatory process, massage may decrease secondary injury, nerve sensitization, and collateral sprouting, resulting in increased recovery from damage and reduction or prevention of pain. Our goal is to provide a framework that describes our current understanding of the mechanisms whereby massage therapy activates potentially beneficial immunomodulatory pathways.

Massage timing affects postexercise muscle recovery and inflammation in a rabbit model

PURPOSE

This study compared the effect of immediate versus delayed massage-like compressive loading (MLL) on peak isometric torque recovery and inflammatory cell infiltration after eccentric exercise (EEX).

METHODS

Eighteen skeletally mature New Zealand White rabbits were instrumented with peroneal nerve cuffs for the stimulation of hindlimb tibialis anterior muscles. After a bout of EEX, rabbits were randomly assigned to an MLL protocol (0.5 Hz, 10 N, 15 min) that started immediately post-EEX, 48 h post-EXX, or no-MLL control and performed for four consecutive days. A torque-angle (T-Θ) relationship was obtained for 21 joint angles pre- and post-EEX and after four consecutive days of MLL or no-MLL. Muscle wet weights and immunohistochemical sections were obtained after final treatments.

RESULTS

EEX produced an average 51% ± 13% decrease in peak isometric torque output. The greatest peak torque recovery occurred with the immediate application of MLL. There were differences in torque recovery between immediate and delayed MLL (P = 0.0012), immediate MLL and control (P < 0.0001), and delayed MLL and control (P = 0.025). Immunohistochemical analysis showed 39.3% and 366.0% differences in the number of RPN3/57 and CD11b-positive cells between immediate (P = 0.71) and delayed MLL (P = 0.12). The area under the T-Θ curve showed a difference for immediate (P < 0.0001) and delayed (P = 0.0051) MLL as compared with control. Exercise produced an average 10° ± 0.2° rightward shift from preexercise peak isometric torque angle. Control, immediate MLL, and delayed MLL produced an average leftward angular shift from the postexercise angle (P = 0.28, P = 0.03, and P = 0.47, respectively).

CONCLUSION

Post-EEX, immediate MLL was more beneficial than delayed MLL in restoring muscle function and in modulating inflammatory cell infiltration. These findings invite similar human studies to make definitive conclusions on optimal timing of massage-based therapies.

Immunomodulatory effects of massage on nonperturbed skeletal muscle in rats

Massage is an ancient manual therapy widely utilized by individuals seeking relief from various musculoskeletal maladies. Despite its popularity, the majority of evidence associated with massage benefits is anecdotal. Recent investigations have uncovered physiological evidence supporting its beneficial use following muscle injury; however, the effects of massage on healthy, unperturbed skeletal muscle are unknown. Utilizing a custom-fabricated massage mimetic device, the purpose of this investigation was to elucidate the effects of various loading magnitudes on healthy skeletal muscle with particular interest in the gene expression profile and modulation of key immune cells involved in the inflammatory response. Twenty-four male Wistar rats (200 g) were subjected to cyclic compressive loading (CCL) over the right tibialis anterior muscle for 30 min, once a day, for 4 consecutive days using four loading conditions: control (0N), low load (1.4N), moderate load (4.5N), and high load (11N). Microarray analysis showed that genes involved with the immune response were the most significantly affected by application of CCL. Load-dependent changes in cellular abundance were seen in the CCL limb for CD68(+) cells, CD163(+) cells, and CD43(+)cells. Surprisingly, load-independent changes were also discovered in the non-CCL contralateral limb, suggesting a systemic response. These results show that massage in the form of CCL exerts an immunomodulatory response to uninjured skeletal muscle, which is dependent upon the applied load.

A mechatronic system for quantitative application and assessment of massage-like actions in small animals

Massage therapy has a long history and has been widely believed effective in restoring tissue function, relieving pain and stress, and promoting overall well-being. However, the application of massage-like actions and the efficacy of massage are largely based on anecdotal experiences that are difficult to define and measure. This leads to a somewhat limited evidence-based interface of massage therapy with modern medicine. In this study, we introduce a mechatronic device that delivers highly reproducible massage-like mechanical loads to the hind limbs of small animals (rats and rabbits), where various massage-like actions are quantified by the loading parameters (magnitude, frequency and duration) of the compressive and transverse forces on the subject tissues. The effect of massage is measured by the difference in passive viscoelastic properties of the subject tissues before and after mechanical loading, both obtained by the same device. Results show that this device is useful in identifying the loading parameters that are most conducive to a change in tissue mechanical properties, and can determine the range of loading parameters that result in sustained changes in tissue mechanical properties and function. This device presents the first step in our effort for quantifying the application of massage-like actions used clinically and measurement of their efficacy that can readily be combined with various quantitative measures (e.g., active mechanical properties and physiological assays) for determining the therapeutic and mechanistic effects of massage therapies.

Dose-dependency of massage-like compressive loading on recovery of active muscle properties following eccentric exercise: rabbit study with clinical relevance

BACKGROUND

Optimal strategies for massage and its use in athletes have not been conclusively demonstrated. PURPOSE/STUDY DESIGN: Effects of varying duration, frequency and magnitude of massage-like compressive loading (MLL) on recovery of skeletal muscle active properties (torque angle (T-Θ) relationship) following exercise-induced muscle injury were studied.

METHODS

Twenty-four New Zealand White rabbits were surgically instrumented with bilateral peroneal nerve cuffs for stimulation of hindlimb tibialis anterior muscles. Following a bout of eccentric exercise (EEX), rabbits were randomly assigned to a MLL protocol of 0.25 or 0.5 Hz at 5 or 10 N for 15 or 30 min. T-Θ was obtained for 21 tibiotarsal joint angles pre- and post-EEX and post 4 consecutive days of MLL. Muscle wet weight and H&E sections were obtained following final treatments.

RESULTS

EEX produced an average 61.8%±2.1 decrease in peak isometric torque output. Differences in torque recovery were found between magnitudes (5 and 10 N; p=0.004, n=12) and frequencies (0.25 and 0.5 Hz; p=0.012, n=12), but no difference for durations (15 and 30 min) with the 0.5 Hz, 10 N, 15 min protocol showing greatest recovery 4 days post-EEX. MLL muscle (n=12) wet weight was 3.22±0.18 g, while no MLL tissue (n=9) weighed 3.74±0.22 g (p=0.029). Histological analysis showed a difference in torn fibres between low-parameter and high-parameter MLL (6.5±1.04 vs 0.5±0.29 per 0.59 mm(2), p=0.005).

CONCLUSIONS

Results showed a dose-response effect for magnitude and frequency of MLL on recovery of active muscle properties following EEX. Future studies will investigate underlying biological mechanisms for this enhanced recovery of muscle function.

Stem cells, angiogenesis and muscle healing: a potential role in massage therapies?

Skeletal muscle injuries are among the most common and frequently disabling injuries sustained by athletes. Repair of injured skeletal muscle is an area that continues to present a challenge for sports medicine clinicians and researchers due, in part, to complete muscle recovery being compromised by development of fibrosis leading to loss of function and susceptibility to re-injury. Injured skeletal muscle goes through a series of coordinated and interrelated phases of healing including degeneration, inflammation, regeneration and fibrosis. Muscle regeneration initiated shortly after injury can be limited by fibrosis which affects the degree of recovery and predisposes the muscle to reinjury. It has been demonstrated in animal studies that antifibrotic agents that inactivate transforming growth factor (TGF)-β1 have been effective at decreasing scar tissue formation. Several studies have also shown that vascular endothelial growth factor (VEGF) can increase the efficiency of skeletal muscle repair by increasing angiogenesis and, at the same time, reducing the accumulation of fibrosis. We have isolated and thoroughly characterised a population of skeletal muscle-derived stem cells (MDSCs) that enhance repair of damaged skeletal muscle fibres by directly differentiating into myofibres and secreting paracrine factors that promote tissue repair. Indeed, we have found that MDSCs transplanted into skeletal and cardiac muscles have been successful at repair probably because of their ability to secrete VEGF that works in a paracrine fashion. The application of these techniques to the study of sport-related muscle injuries awaits investigation. Other useful strategies to enhance skeletal muscle repair through increased vascularisation may include gene therapy, exercise, neuromuscular electrical stimulation and, potentially, massage therapy. Based on recent studies showing an accelerated recovery of muscle function from intense eccentric exercise through massage-based therapies, we believe that this treatment modality offers a practical and non-invasive form of therapy for skeletal muscle injuries. However, the biological mechanism(s) behind the beneficial effect of massage are still unclear and require further investigation using animal models and potentially randomised, human clinical studies.

In vivo passive mechanical properties of skeletal muscle improve with massage-like loading following eccentric exercise

A quasi-linear viscoelasticity (QLV) model was used to study passive time-dependent responses of skeletal muscle to repeated massage-like compressive loading (MLL) following damaging eccentric exercise. Six skeletally mature rabbits were surgically instrumented with bilateral peroneal nerve cuffs for stimulation of the hindlimb tibialis anterior (TA) muscles. Following the eccentric exercise, rabbits were randomly assigned to a four-day MLL protocol mimicking deep effleurage (0.5 Hz, 10 N for 15 min or for 30 min). The contralateral hindlimb served as the exercised, no-MLL control for both MLL conditions. Viscoelastic properties of the muscle pre-exercise, post-exercise on Day 1, and pre- and post-MLL Day 1 through Day 4 were determined with ramp-and-hold tests. The instantaneous elastic response (AG(0)) increased following exercise (p<0.05) and decreased due to both the 15 min and 30 min four-day MLL protocols (p<0.05). Post-four days of MLL the normalized AG(0) decreased from post-exercise (Day 1, 248.5%) to the post-MLL (Day 4, 98.5%) (p<0.05), compared to the no-MLL group (Day 4, 222.0%) (p<0.05). Exercise and four-day MLL showed no acute or cumulative effects on the fast and slow relaxation coefficients (p>0.05). This is the first experimental evidence of the effect of both acute (daily) and cumulative changes in viscoelastic properties of intensely exercised muscle due to ex vivo MLL. It provides a starting point for correlating passive muscle properties with mechanical effects of manual therapies, and may shed light on design and optimization of massage protocols.

Effect of five different recovery methods on repeated cycle performance

PURPOSE

The aim of this study was to determine the influence of five different recovery strategies on repeated simulated time trial (TT) performance on a stationary cycle ergometer.

METHODS

Study 1 (n=8, male, club-level trained; V˙O2max: 56.9 ± 3.8 mL·min·kg) investigated the influence of passive rest with or without upper leg cooling (cooling device set at 0 °C or 10 °C) and compression after a first time trial (TT1) on a second time trial (TT2). Study 2 (n=9, male, club-level trained; V˙O2max: 53.3 ± 5.2 mL·min·kg) examined the influence of active recovery (AR) with or without upper leg cooling (cooling device set at 0 °C) applied after TT1 on TT2. Exhaustive exercise consisted of a cycle exercise at 55% Wmax lasting 30 min, immediately followed by a TT in which subjects had to complete a preset amount of work, equal to 30 min at 75% Wmax, as fast as possible. Immediately after TT1, a different recovery intervention was used for 20 min, and then subjects passively rested for 100 min before starting TT2. TT performance and physiological parameters were registered during the experiments.

RESULTS

In both studies, we observed that TT performance did not significantly change for either of the recovery interventions. During the cooling interventions, skin temperatures significantly decreased (P<0.05). AR + cooling + compression versus AR (study 2) clearly showed a significantly (P<0.05) faster decrease of the blood lactate concentration ([BLa]) during the recovery period after TT1 and a lower [BLa] during TT2.

CONCLUSIONS

Twenty minutes after cooling (device set at 0 °C or 10 °C), AR or the combined recovery method had comparable effects as passive recovery on the maintenance of TT2 performance 120 min after the first TT (TT1). After AR, however, subjects seemed to perform slightly better during TT2.

Efeito da massagem clássica na percepção subjetiva de dor, edema, amplitude articular e força máxima após dor muscular tardia induzida pelo exercício

O treino de força com cargas elevadas tem induzido indivíduos a apresentarem sintomas de dano muscular que incluem a dor muscular tardia. Na tentativa de diminuir sintomas e desconforto da DOMS, estratégias têm sido utilizadas, entre elas, a massagem. O objetivo do presente estudo foi verificar os efeitos da massagem clássica na percepção subjetiva de dor (DOMS), circunferência do braço (CIR), amplitude de movimento (ADM) e força máxima (1RM) após protocolo para indução de DOMS. Para isso, 18 adultos jovens saudáveis do gênero masculino foram divididos em três grupos (G1 = massagem; G2 = protocolo; G3 = protocolo + massagem) equalizados pelo teste de uma força máxima de flexão de cotovelo no banco Scott. O protocolo de indução de DOMS consistiu de 30 ações excêntricas musculares supramáximas (seis séries de cinco repetições a 110% de 1RM). A massagem foi realizada no grupo G3 imediatamente após o protocolo durante seis minutos. As variáveis dependentes (DOMS, CIR, ADM) foram avaliadas 24, 48, 72 e 96 horas após o protocolo, enquanto a força máxima, apenas após 48 e 96 horas. Os resultados indicaram aumento na DOMS e diminuição na ADM e 1RM, similar aos de outros estudos que utilizaram protocolos semelhantes. No entanto, não houve diferenças entre os grupos G2 e G3 em nenhuma das variáveis analisadas. Pode-se concluir que com esse design experimental o protocolo utilizado foi eficaz para provocar as alterações nas variáveis analisadas e a massagem não causou nenhum benefício na recuperação das funções musculares nem na percepção subjetiva de dor.