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Sports Health 2017The medial head of the gastrocnemius is the third most commonly strained muscle in elite athletes after the biceps femoris and rectus femoris. The differential diagnosis... (Review)
Review
CONTEXT
The medial head of the gastrocnemius is the third most commonly strained muscle in elite athletes after the biceps femoris and rectus femoris. The differential diagnosis of posterior calf injury includes musculoskeletal and nonmusculoskeletal causes. Classically, delineation of these injuries from one another relied primarily on historical features and physical examination findings. The utilization of musculoskeletal ultrasound (sonography) has augmented the diagnosis of these injuries by providing dynamic, real-time confirmation.
EVIDENCE ACQUISITION
A review of PubMed, OVID, and MD Consult prior to January 2016 was performed using search terms, including s oleus ultrasound, gastrocnemius ultrasound, and tennis leg. The references of the pertinent articles were further reviewed for other relevant sources.
STUDY DESIGN
Clinical review.
LEVEL OF EVIDENCE
Level 4.
RESULTS
There have been few reviews to date of calf injuries and the use of sonography in their diagnosis. Prompt diagnosis utilizing ultrasound allows the clinician to focus management on gastrocnemius injury if present. Two-thirds of calf injuries occur at the junction of the fascia between the medial head of the gastrocnemius and the soleus. Injuries to the lateral head of the gastrocnemius occur in up to 14% of patients in some case series, but injury may occur anywhere from the proximal origin to the mid-belly to the fascial junction with the soleus. Numerous injuries to the posterior compartment can mimic gastrocnemius strain, and musculoskeletal ultrasound can aide in their diagnosis by incorporating real-time imaging into the grading of the injury and visual confirmation of physical examination findings.
CONCLUSION
Acute injury to the posterior compartment of the lower extremity can represent a diagnostic challenge. Medial gastrocnemius strain represents the most common injury of the posterior compartment of the lower extremity. Ultrasound is a useful tool to assist the clinician in determining the specific cause of calf injury, estimate the severity of the injury, and monitor progress of healing. The vast majority of calf injuries can be diagnosed and managed without any additional imaging. Serial diagnostic ultrasound of an injured area allows for direct monitoring of tissue healing and may allow the clinician to more confidently assess response to treatment and help guide return-to-play decisions.
Topics: Athletic Injuries; Humans; Leg Injuries; Muscle, Skeletal; Sprains and Strains; Ultrasonography
PubMed: 28661826
DOI: 10.1177/1941738117696019 -
Journal of Cachexia, Sarcopenia and... Aug 2022Skeletal muscle exhibits remarkable plasticity under both physiological and pathological conditions. One major manifestation of this plasticity is muscle atrophy that is...
BACKGROUND
Skeletal muscle exhibits remarkable plasticity under both physiological and pathological conditions. One major manifestation of this plasticity is muscle atrophy that is an adaptive response to catabolic stimuli. Because the heterogeneous transcriptome responses to catabolism in different types of muscle cells are not fully characterized, we applied single-nucleus RNA sequencing (snRNA-seq) to unveil muscle atrophy related transcriptional changes at single nucleus resolution.
METHODS
Using a sciatic denervation mouse model of muscle atrophy, snRNA-seq was performed to generate single-nucleus transcriptional profiles of the gastrocnemius muscle from normal and denervated mice. Various bioinformatics analyses, including unsupervised clustering, functional enrichment analysis, trajectory analysis, regulon inference, metabolic signature characterization and cell-cell communication prediction, were applied to illustrate the transcriptome changes of the individual cell types.
RESULTS
A total of 29 539 muscle nuclei (normal vs. denervation: 15 739 vs. 13 800) were classified into 13 nuclear types according to the known cell markers. Among these, the type IIb myonuclei were further divided into two subgroups, which we designated as type IIb1 and type IIb2 myonuclei. In response to denervation, the proportion of type IIb2 myonuclei increased sharply (78.12% vs. 38.45%, P < 0.05). Concomitantly, trajectory analysis revealed that denervated type IIb2 myonuclei clearly deviated away from the normal type IIb2 myonuclei, indicating that this subgroup underwent robust transcriptional reprogramming upon denervation. Signature genes in denervated type IIb2 myonuclei included Runx1, Gadd45a, Igfn1, Robo2, Dlg2, and Sh3d19 (P < 0.001). The gene regulatory network analysis captured a group of atrophy-related regulons (Foxo3, Runx1, Elk4, and Bhlhe40) whose activities were enhanced (P < 0.01), especially in the type IIb2 myonuclei. The metabolic landscape in the myonuclei showed that most of the metabolic pathways were down-regulated by denervation (P < 0.001), while some of the metabolic signalling, such as glutathione metabolism, was specifically activated in the denervated type IIb2 myonulei. We also investigated the transcriptomic alterations in the type I myofibres, muscle stem cells, fibro-adipogenic progenitors, macrophages, endothelial cells and pericytes and characterized their signature responses to denervation. By predicting the cell-cell interactions, we observed that the communications between myofibres and muscle resident cells were diminished by denervation.
CONCLUSIONS
Our results define the myonuclear transition, metabolic remodelling, and gene regulation networks reprogramming associated with denervation-induced muscle atrophy and illustrate the molecular basis of the heterogeneity and plasticity of muscle cells in response to catabolism. These results provide a useful resource for exploring the molecular mechanism of muscle atrophy.
Topics: Animals; Denervation; Endothelial Cells; Mice; Muscle, Skeletal; Muscular Atrophy; RNA, Small Nuclear; Transcriptome
PubMed: 35726356
DOI: 10.1002/jcsm.13023 -
Physiological Reports Aug 2017The purpose of this study was to compare the effects of plyometric and isometric training on tendon properties during ramp and ballistic contractions and muscle...
The purpose of this study was to compare the effects of plyometric and isometric training on tendon properties during ramp and ballistic contractions and muscle stiffness under passive and active conditions. Eleven subjects completed 12 weeks (3 days/week) of a unilateral training program for the plantar flexors. They performed plyometric training on one side (PLY) and isometric training on the other side (ISO). Active muscle stiffness in the medial gastrocnemius muscle was calculated according to changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Passive muscle stiffness was also calculated from estimated passive muscle force and fascicle length during slow passive stretching. Stiffness and hysteresis of tendon structures were measured using ultrasonography during ramp and ballistic contractions. Passive muscle stiffness and tendon hysteresis did not change for PLY or ISO Active muscle stiffness significantly increased for PLY, but not for ISO Tendon stiffness during ramp and ballistic contractions increased significantly for ISO, but not for PLY In addition, tendon elongation values at force production levels beyond 100 N during ballistic contractions increased for PLY These results suggest that plyometric training (but not isometric training) enhances the extensibility of tendon structures during ballistic contractions and active muscle stiffness during fast stretching, and these changes may be related to improved performances during stretch-shortening cycle exercises.
Topics: Adult; Exercise; Humans; Isometric Contraction; Male; Muscle, Skeletal; Plyometric Exercise; Tendons; Young Adult
PubMed: 28801518
DOI: 10.14814/phy2.13374 -
Theranostics 2020: Peripheral nerve injury is common in clinic, which leads to severe atrophy and dysfunction of the denervated muscles, but the underlying mechanism is not fully...
: Peripheral nerve injury is common in clinic, which leads to severe atrophy and dysfunction of the denervated muscles, but the underlying mechanism is not fully understood. Recent studies advanced the causative role of mitochondrial dysfunction in muscle atrophy, while the upstream triggers remained unclear. : In the present study, Atrophy of gastrocnemius and tibialis anterior (TA) were evaluated in mice sciatic nerve transection model. Transmission electron microscopy (TEM) was then used to observe the microstructure of atrophic gastrocnemius and mitochondria. Subsequently, small RNA sequencing, luciferase reporter assay and Electrophoretic Mobility Shift (EMSA) were performed to explore the potential signaling pathway involved in skeletal muscle atrophy. The effects of the corresponding pathway on mitochondrial function, mitophagy, apoptosis and muscle atrophy were further determined in C2C12 cells and denervated gastrocnemius. : Gastrocnemius and TA atrophied rapidly after denervation. Obvious decrease of mitochondria number and activation of mitophagy was further observed in atrophic gastrocnemius. Further, miR-142a-5p/ mitofusin-1 (MFN1) axis was confirmed to be activated in denervated gastrocnemius, which disrupted the tubular mitochondrial network, and induced mitochondrial dysfunction, mitophagy and apoptosis. Furthermore, the atrophy of gastrocnemius induced by denervation was relieved through targeting miR-142a-5p/MFN1 axis. : Collectively, our data revealed that miR-142a-5p was able to function as an important regulator of denervation-induced skeletal muscle atrophy by inducing mitochondrial dysfunction, mitophagy, and apoptosis via targeting MFN1. Our findings provide new insights into the mechanism of skeletal muscle atrophy following denervation and propose a viable target for therapeutic intervention in individuals suffering from muscle atrophy after peripheral nerve injury.
Topics: Animals; Apoptosis; Cell Line; Denervation; GTP Phosphohydrolases; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Mitochondria; Mitophagy; Muscle Denervation; Muscle, Skeletal; Muscular Atrophy; Myoblasts; Sciatic Nerve
PubMed: 31938072
DOI: 10.7150/thno.40857 -
BMC Musculoskeletal Disorders Aug 2022Extensive muscle atrophy is a common occurrence in orthopaedics patients who are bedridden or immobilized. The incidence is higher in intensive care unit (ICU)... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Extensive muscle atrophy is a common occurrence in orthopaedics patients who are bedridden or immobilized. The incidence is higher in intensive care unit (ICU) inpatients. There is still controversy about how to use neuromuscular electrical stimulation (NMES) in ICU patients. We aim to compare the effectiveness and safety of NMES to prevent muscle atrophy in intensive care unit (ICU) patients without nerve injury.
METHODS
ICU patients without central and peripheral nerve injury were randomized into experimental group I (Exp I: active and passive activity training (APAT) + NMES treatment on the gastrocnemius and tibialis anterior muscle), experimental group II (Exp II: APAT + NMES treatment on gastrocnemius alone), and control group (Ctl: APAT alone). Changes in the strength of gastrocnemius, the ankle range of motion, and the muscle cross-section area of the lower leg were evaluated before and after the intervention. Also, changes in prothrombin time, lactic acid, and C-reactive protein were monitored during the treatment.
RESULTS
The gastrocnemius muscle strength, ankle joint range of motion, and cross-sectional muscle area of the lower leg in the three groups showed a downward trend, indicating that the overall trend of muscle atrophy in ICU patients was irreversible. The decrease in gastrocnemius muscle strength in Exp I and Exp II was smaller than that in the control group (P < 0.05), but there was no difference between Exp I and Exp II. The decrease in active ankle range of motion and cross-sectional area of the lower leg Exp I and Exp II was smaller than that in the control group (P < 0.05), and the decrease in Exp I was smaller than that of Exp II (all P < 0.05). The curative effect in Exp I was better than in Exp II. There were no significant differences in the dynamic changes of prothrombin time, lactic acid, and C-reactive protein during the three groups (P > 0.05).
CONCLUSION
In addition to early exercise training, NMES should be applied to prevent muscle atrophy for patients without nerve injury in ICU. Also, simultaneous NMES treatment on agonist/antagonist muscle can enhance the effect of preventing muscle atrophy.
TRIAL REGISTRATION
This study was prospectively registered in China Clinical Trial Registry ( www.chictr.org.cn ) on 16/05/2020 as ChiCTR2000032950.
Topics: C-Reactive Protein; Electric Stimulation Therapy; Humans; Intensive Care Units; Lactic Acid; Muscle Strength; Muscle, Skeletal; Muscular Atrophy
PubMed: 35974369
DOI: 10.1186/s12891-022-05739-2 -
Aging Cell Oct 2023Sarcopenia is characterized of muscle mass loss and functional decline in elder individuals which severely affects human physical activity, metabolic homeostasis, and...
Sarcopenia is characterized of muscle mass loss and functional decline in elder individuals which severely affects human physical activity, metabolic homeostasis, and life quality. Physical exercise is considered effective in combating muscle atrophy and sarcopenia, yet it is not feasible to elders with limited mobility. PGC-1α4, a short isoform of PGC-1α, is strongly induced in muscle under resistance training, and promotes muscle hypertrophy. In the present study, we showed that the transcriptional levels and nuclear localization of PGC1α4 was reduced during aging, accompanied with muscle dystrophic morphology, and gene programs. We thus designed NLS-PGC1α4 and ectopically express it in myotubes to enhance PGC1α4 levels and maintain its location in nucleus. Indeed, NLS-PGC1α4 overexpression increased muscle sizes in myotubes. In addition, by utilizing AAV-NLS-PGC1α4 delivery into gastrocnemius muscle, we found that it could improve sarcopenia with grip strength, muscle weights, fiber size and molecular phenotypes, and alleviate age-associated adiposity, insulin resistance and hepatic steatosis, accompanied with altered gene signatures. Mechanistically, we demonstrated that NLS-PGC-1α4 improved insulin signaling and enhanced glucose uptake in skeletal muscle. Besides, via RNA-seq analysis, we identified myokines IGF1 and METRNL as potential targets of NLS-PGC-1α4 that possibly mediate the improvement of muscle and adipose tissue functionality and systemic energy metabolism in aged mice. Moreover, we found a negative correlation between PGC1α4 and age in human skeletal muscle. Together, our results revealed that NLS-PGC1α4 overexpression improves muscle physiology and systematic energy homeostasis during aging and suggested it as a potent therapeutic strategy against sarcopenia and aging-associated metabolic diseases.
Topics: Mice; Humans; Animals; Aged; Sarcopenia; Aging; Muscle, Skeletal; Muscle Fibers, Skeletal; Transcription Factors
PubMed: 37584432
DOI: 10.1111/acel.13961 -
The Journal of Physiology Jun 2023This study aimed to clarify whether aerobic exercise training-induced alterations in the gut microbiota affect physiological adaptation with endurance exercise capacity....
This study aimed to clarify whether aerobic exercise training-induced alterations in the gut microbiota affect physiological adaptation with endurance exercise capacity. In study 1, ICR mice were randomly divided into three groups: vehicle intake + sedentary (V+S), vehicle intake + exercise training (V+Ex) and antibiotic intake + exercise training (AB+Ex). In the exercise training groups, treadmill running was performed for 8 weeks. During the exercise training intervention, the antibiotic-intake group freely drank water containing antibiotics. In study 2, ICR mice were randomly divided into three groups: Sham, transplantation of caecum microbiota from sedentary mice (Sed-CMT) and exercise training mice (Ex-CMT). In study 1, the treadmill running time to exhaustion, an index of maximal aerobic capacity, after aerobic exercise training in the V+Ex group was significantly longer than that in the V+S and AB+Ex groups. Gastrocnemius muscle citrate synthase (CS) activity and PGC-1α protein levels in the V+Ex group were significantly higher than in the V+S and AB+Ex groups. The bacterial Erysipelotrichaceae and Alcaligenaceae families were positively correlated with treadmill running time to exhaustion. In study 2, the treadmill running time to exhaustion after transplantation was significantly higher in the Ex-CMT group than in the Sham and Sed-CMT groups. Furthermore, CS activity and PGC-1α protein levels in the gastrocnemius muscle were significantly higher in the Ex-CMT group than in the Sham and Sed-CMT groups. Thus, gut microbiota altered by aerobic exercise training may be involved in the augmentation of endurance capacity and muscle mitochondrial energy metabolism. KEY POINTS: Aerobic exercise training changes gut microbiota composition, and the Erysipelotrichaceae and Alcaligenaceae families were among the altered gut bacteria. The gut microbiota was associated with endurance performance and metabolic regulator levels in skeletal muscle after aerobic exercise training. Continuous antibiotic treatment attenuated the increase in endurance performance, citrate synthase activity and PGC-1α levels in skeletal muscle induced by aerobic exercise training. Gut microbiota transplantation from exercise-trained mice improved endurance performance and metabolic regulator levels in recipient skeletal muscle, despite the absence of aerobic exercise training.
Topics: Mice; Animals; Gastrointestinal Microbiome; Physical Conditioning, Animal; Mice, Inbred ICR; Citrate (si)-Synthase; Physical Endurance; Muscle, Skeletal; Anti-Bacterial Agents
PubMed: 37056044
DOI: 10.1113/JP283995 -
International Journal of Molecular... Jun 2022Disuse muscle atrophy is identified as the physiological, biochemical, morphological, and functional changes during restricted movement, immobilization, or...
Disuse muscle atrophy is identified as the physiological, biochemical, morphological, and functional changes during restricted movement, immobilization, or weightlessness. Although its internal mechanism has been extensively studied in mammals and was thought to be mainly related to oxidative stress, it was unclear whether it behaved consistently in non-mammals such as chickens. In this study, we tried to construct a disuse atrophy model of the gastrocnemius muscle in chickens by limb immobilization, and collected the gastrocnemius muscles of the fixed group and the control group for RNA sequencing. Through analysis of muscle loss, HE staining, immunohistochemistry, and oxidative stress level, we found that limb immobilization could lead to loss of muscle mass, decrease in muscle fiber diameter, decrease in the proportion of slow muscle fibers, and increase in the proportion of fast muscle fibers, and also cause elevated levels of oxidative stress. In addition, a total of 565 different expression genes (DEGs) were obtained by RNA sequencing, which was significantly enriched in the biological processes such as cell proliferation and apoptosis, reactive oxygen species metabolism, and fast and slow muscle fiber transformation, and it showed that the FOXO signaling pathway, closely related to muscle atrophy, was activated. In brief, we initially confirmed that limb immobilization could induce disuse atrophy of skeletal muscle, and oxidative stress was involved in the process of disuse muscle atrophy.
Topics: Animals; Chickens; Mammals; Muscle Fibers, Skeletal; Muscle, Skeletal; Muscular Atrophy; Muscular Disorders, Atrophic
PubMed: 35805900
DOI: 10.3390/ijms23136892 -
Journal of Orthopaedic Surgery and... Apr 2023The calcaneal tendon, the largest and strongest in the human body, is created by the common junction of tendons of the gastrocnemius and soleus muscles. It is not a... (Review)
Review
The calcaneal tendon, the largest and strongest in the human body, is created by the common junction of tendons of the gastrocnemius and soleus muscles. It is not a homogenous structure, being represented by layers in various arrangements. Morphological variability can be seen in the connection between the aponeurosis of the gastrocnemius muscle and the soleus muscle. Some types of plantaris tendon can be associated with a higher possibility of Achilles tendinopathy. Moreover, the presence of accessory structures, such as an accessory soleus muscle or additional gastrocnemius muscle heads may result in symptomatic pathologies. The main aim of this review is to summarize the current state of knowledge regarding the calcaneal tendon. Another aim is to present morphological variations of the calcaneal tendon and their clinical significance. Such information may be useful for clinicians, especially orthopedists, and surgeons. This review also provides an overview of embryological development and morphological variation among fetuses. Materials and methods: review was conducted according to PRISMA guidelines. An electronic search was conducted in five databases. Top quality tools were used to assess the quality of evidence in the studies reviewed. Research papers that made up the database of this review were analyzed, selected and assessed by two independently working researchers.
Topics: Humans; Achilles Tendon; Clinical Relevance; Tendinopathy; Muscle, Skeletal; Foot
PubMed: 37016428
DOI: 10.1186/s13018-023-03748-y -
Journal of Electromyography and... Jun 2023The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs),... (Review)
Review
The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs), which have different contractile properties and play different roles in generating muscle force. Second, whole muscle activity is an effect of net excitatory inputs to a pool of motoneurons innervating the muscle, which have different excitability, influencing MU recruitment. In this review, we compare various methods for modeling MU twitch and tetanic forces and then discuss muscle models composed of different MU types and number. We first present four different analytical functions used for twitch modeling and show limitations related to the number of twitch describing parameters. We also show that a nonlinear summation of twitches should be considered in modeling tetanic contractions. We then compare different muscle models, most of which are variations of Fuglevand's model, adopting a common drive hypothesis and the size principle. We pay attention to integrating previously developed models into a consensus model based on physiological data from in vivo experiments on the rat medial gastrocnemius muscle and its respective motoneurons. Finally, we discuss the shortcomings of existing models and potential applications for studying MU synchronization, potentiation, and fatigue.
Topics: Rats; Animals; Muscle, Skeletal; Muscle Contraction; Motor Neurons; Electric Stimulation
PubMed: 37099899
DOI: 10.1016/j.jelekin.2023.102774