The 24-hour molecular landscape after exercise in humans reveals MYC is sufficient for muscle growth.

A detailed understanding of molecular responses to a hypertrophic stimulus in skeletal muscle leads to therapeutic advances aimed at promoting muscle mass. To decode the molecular factors regulating skeletal muscle mass, we utilized a 24-h time course of human muscle biopsies after a bout of resistance exercise. Our findings indicate: (1) the DNA methylome response at 30 min corresponds to upregulated genes at 3 h, (2) a burst of translation- and transcription-initiation factor-coding transcripts occurs between 3 and 8 h, (3) changes to global protein-coding gene expression peaks at 8 h, (4) ribosome-related genes dominate the mRNA landscape between 8 and 24 h, (5) methylation-regulated MYC is a highly influential transcription factor throughout recovery.

The 24-Hour Time Course of Integrated Molecular Responses to Resistance Exercise in Human Skeletal Muscle Implicates as a Hypertrophic Regulator That is Sufficient for Growth.

Molecular control of recovery after exercise in muscle is temporally dynamic. A time course of biopsies around resistance exercise (RE) combined with -omics is necessary to better comprehend the molecular contributions of skeletal muscle adaptation in humans. Vastus lateralis biopsies before and 30 minutes, 3-, 8-, and 24-hours after acute RE were collected.

Current Guidelines for the Implementation of Flywheel Resistance Training Technology in Sports: A Consensus Statement.

Background: Flywheel resistance training has become more integrated within resistance training programs in a variety of sports due to the neuromuscular, strength, and task-specific enhancements reported with this training.

Objective: This paper aimed to present the consensus reached by internationally recognized experts during a meeting on current definitions and guidelines for the implementation of flywheel resistance training technology in sports.

Methods: Nineteen experts from different countries took part in the consensus process; 16 of them were present at the consensus meeting (18 May 2023) while three submitted their recommendations by e-mail.

Microgravity-induced skeletal muscle atrophy in women and men: implications for long-duration spaceflights to the Moon and Mars.

The inclusion of women on spaceflights has historically been limited. Recently, the first woman who will travel to the Moon was selected, and more women are participating in long-duration spaceflights. However, physiological data from real and simulated microgravity exposure are limited in women.

Extracellular vesicle characteristics and microRNA content in cerebral palsy and typically developed individuals at rest and in response to aerobic exercise.

In this study, the properties of circulating extracellular vesicles (EVs) were examined in cerebral palsy (CP) and typically developed (TD) individuals at rest and after aerobic exercise, focusing on the size, concentration, and microRNA cargo of EVs. Nine adult individuals with CP performed a single exercise bout consisting of 45 min of Frame Running, and TD participants completed either 45 min of cycling ( = 10; TD EX) or were enrolled as controls with no exercise ( = 10; TD CON). Blood was drawn before and 30 min after exercise and analyzed for EV concentration, size, and microRNA content.

A prophylactic subcutaneous dose of the anticoagulant tinzaparin does not influence qPCR-based assessment of circulating levels of miRNA in humans.

Circulating microRNAs (miRNAs) have become increasingly popular biomarker candidates in various diseases. However, heparin-based anticoagulants might affect the detection of target miRNAs in blood samples during quantitative polymerase chain reaction (qPCR)-based analysis of miRNAs involving RNA extraction, cDNA synthesis and the polymerase catalyzed reaction. Because low-molecular-weight heparins (LMWH) are widely used in routine healthcare, we aimed to investigate whether a prophylactic dose of the LMWH tinzaparin influences qPCR-based quantification of circulating miRNAs.

Reliability and Validity of an Ultrasound-Based Protocol for Measurement of Quadriceps Muscle Thickness in Children.

Accurate determination of skeletal muscle size is of great importance in multiple settings including resistance exercise, aging, disease, and disuse. Ultrasound (US) measurement of muscle thickness (MT) is a method of relatively high availability and low cost. The present study aims to evaluate a multisite ultrasonographic protocol for measurement of MT with respect to reproducibility and correlation to gold-standard measurements of muscle volume (MV) with magnetic resonance imaging (MRI) in children.

BioFACTS: biomarkers of rhabdomyolysis in the diagnosis of acute compartment syndrome - protocol for a prospective multinational, multicentre study involving patients with tibial fractures.

Introduction: The ischaemic pain of acute compartment syndrome (ACS) can be difficult to discriminate from the pain linked to an associated fracture. Lacking objective measures, the decision to perform fasciotomy is based on clinical findings and performed at a low level of suspicion. Biomarkers of muscle cell damage may help to identify and monitor patients at risk, similar to current routines for patients with acute myocardial infarction.

Acute endurance exercise stimulates circulating levels of mitochondrial-derived peptides in humans.

Mitochondrial-derived peptides (MDPs) humanin (HN) and mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) are involved in cell survival, suppression of apoptosis, and metabolism. Circulating levels of MDPs are altered in chronic diseases such as diabetes type 2 and chronic kidney disease. Whether acute resistance (RE) or endurance (EE) exercise modulates circulating levels of HN and MOTS-c in humans is unknown.

Mechanical overload-induced muscle-derived extracellular vesicles promote adipose tissue lipolysis.

How regular physical activity is able to improve health remains poorly understood. The release of factors from skeletal muscle following exercise has been proposed as a possible mechanism mediating such systemic benefits. We describe a mechanism wherein skeletal muscle, in response to a hypertrophic stimulus induced by mechanical overload (MOV), released extracellular vesicles (EVs) containing muscle-specific miR-1 that were preferentially taken up by epidydimal white adipose tissue (eWAT).

STOP leg clots-Swedish multicentre trial of outpatient prevention of leg clots: study protocol for a randomised controlled trial on the efficacy of intermittent pneumatic compression on venous thromboembolism in lower leg immobilised patients.

Introduction: Leg immobilisation in a cast or an orthosis after lower limb injuries is associated with a high risk of complications of venous thromboembolism (VTE) and hampered healing. Current pharmacoprophylaxes of VTE are inefficient and associated with adverse events. Intermittent pneumatic compression (IPC) could represent a novel, efficient and safe VTE-prophylactic alternative that may enhance injury healing.

Genetic and epigenetic regulation of skeletal muscle ribosome biogenesis with exercise.

Key Points: Ribosome biogenesis and MYC transcription are associated with acute resistance exercise (RE) and are distinct from endurance exercise in human skeletal muscle throughout a 24 h time course of recovery. A PCR-based method for relative ribosomal DNA (rDNA) copy number estimation was validated by whole genome sequencing and revealed that rDNA dosage is positively correlated with ribosome biogenesis in response to RE. Acute RE modifies rDNA methylation patterns in enhancer, intergenic spacer and non-canonical MYC-associated regions, but not the promoter.

Comparison of use of plaster casting versus elastic bandage following carpal tunnel release: a randomized controlled study.

Objective: To compare the effects of two postoperative regimens following carpal tunnel release; plaster casting and elastic bandaging.

Design: A randomized controlled study.

Patients: Patients with carpal tunnel syndrome and planned surgical carpal tunnel release were invited to participate.

Three months of bed rest induce a residual transcriptomic signature resilient to resistance exercise countermeasures.

This study explored the muscle genome-wide response to long-term unloading (84-day bed rest) in 21 men. We hypothesized that a part of the bed rest-induced gene expression signature would be resilient to a concurrent flywheel resistance exercise (RE) countermeasure. Using DNA microarray technology analyzing 35 345 gene-level probe-sets, we identified 335 annotated probe-sets that were downregulated, and 315 that were upregulated after bed rest (P < .

Effect of acute transcranial magnetic stimulation on intracellular signalling in human skeletal muscle.

Objective: To investigate the potential of an acute bout of transcranial electrical stimulation to induce anabolic signalling.

Design: Experimental intervention on healthy subjects.

Subjects: Ten healthy subjects, 5 women and 5 men (mean age (standard deviation (SD) 32 years (SD 4)).

Muscle Activation During Gravity-Independent Resistance Exercise Compared to Common Exercises.

The aim was to study quadriceps muscle activation during resistance exercise using a flywheel device, developed as a gravity-independent resistance exercise device to be used during spaceflight, compared with traditional strength training exercises. Eight healthy men experienced in resistance exercise performed the following exercises in random order: flywheel leg press (FW), knee extension isokinetic dynamometry (ID), barbell front squat (FS), weight stack leg press (LP), and weight stack knee extension (KE). They accomplished eight repetitions of coupled concentric and eccentric actions with simultaneous recordings of surface electromyography (EMG) from the three superficial quadriceps muscles and knee angles using electrogoniometry.

Low compartment pressure and myoglobin levels in tibial fractures with suspected acute compartment syndrome.

Background: The intense ischemic pain of acute compartment syndrome can be difficult to discriminate from the pain related to an associated fracture. Lacking objective measures, the decision to perform fasciotomy is often only based on clinical findings and performed at a low threshold. Biomarkers of muscle cell damage might help to identify and monitor patients at risk.

Effect of postoperative pneumatic compression after volar plate fixation of distal radial fractures: a randomized controlled trial.

Unlabelled: We investigated the difference between postoperative rehabilitation with or without adjunctive intermittent pneumatic compression therapy following distal radial fracture treated with volar plating. A total of 115 patients were randomized to a control or to an experimental group. After 4 weeks of immobilization the experimental group received intermittent pneumatic compression therapy in addition to conventional postoperative rehabilitation.

Neuromuscular Adaptations Following 90 Days Bed Rest With or Without Resistance Exercise.

Introduction: This study examined the effects of long-term bed rest with or without a concurrent resistance exercise protocol on different muscle function indices of the knee extensors and their influence on previously shown atrophy, neural impairment, and slow-to-fast phenotype shift.

Methods: Nine men underwent 90 d of bed rest only (BR), while eight men in addition performed maximal supine squats every third day (BRE). Before and at day 1 and 5 following bed rest, surface quadriceps electromyographic (EMG) activity was measured during a sustained (60-s) submaximal isometric action and rate of force development (RFD) was assessed during a maximal isometric action, both in the supine squat position.

Muscle-fiber conduction velocity during concentric and eccentric actions on a flywheel exercise device.

A gravity-independent flywheel exercise device (FWED) has been proven effective as a countermeasure to loss of strength and muscle atrophy induced by simulated microgravity. This study assessed muscle-fiber conduction velocity (CV) and surface EMG instantaneous mean power spectral frequency (iMNF) during brief bouts of fatiguing concentric (CON) and eccentric (ECC) exercise on a FWED in order to identify electromyographic (EMG) variables that can be used to provide objective indications of muscle status when exercising with a FWED. Multichannel surface EMG signals were recorded from vastus lateralis and medialis muscles of nine men during: (1) isometric, 60-s action at 50% of maximum voluntary action (MVC); (2) two isometric, linearly increasing force ramps (0-100% MVC); and (3) dynamic CON/ECC coupled actions on the FWED.

Effects of 84-days of bedrest and resistance training on single muscle fibre myosin heavy chain distribution in human vastus lateralis and soleus muscles.

Aim: This investigation determined the effects of 84 days of bedrest on the composition of myosin heavy chain (MHC) in single skeletal muscle fibres with and without a resistance-training countermeasure programme.

Methods: Muscle biopsies were obtained from the m. vastus lateralis (VL) and m.

Muscle atrophy and bone loss after 90 days' bed rest and the effects of flywheel resistive exercise and pamidronate: results from the LTBR study.

Muscle atrophy and bone loss pose substantial problems for long-term space flight and in clinical immobilization. We therefore tested the efficacy of flywheel resistive exercise and pamidronate to counteract such losses. Twenty five young healthy males underwent strict bed rest with -6 degrees head-down tilt for 90 days.

Knee extensor and plantar flexor muscle size and function following 90 days of bed rest with or without resistance exercise.

Skeletal muscle atrophy and strength loss induced by short-term simulated spaceflight are offset or attenuated by resistance exercise (RE). This study compared the effects of plantar flexor and knee extensor RE on muscle size and function in 17 healthy men (aged 26-41years) subjected to 90 days 6 degrees head-down-tilt bed rest with (BRE; n = 8) or without (BR; n = 9) RE. The RE program consisted of coupled maximal concentric and eccentric actions in the supine squat (4 sets of 7 repetitions) and calf press (4 x 14) every third day employing a gravity-independent flywheel ergometer (FW).

Efficacy of a gravity-independent resistance exercise device as a countermeasure to muscle atrophy during 29-day bed rest.

Aim: This study determined changes in knee extensor and plantar flexor muscle volume during 29 days of bed rest with or without resistance exercise using a gravity-independent flywheel ergometer.

Methods: Seventeen men (26-41 years) were subjected to 29 days of bed rest with (n = 8) or without (n = 9) resistance exercise; Supine Squat (SS) and Calf Press (CP) performed every third day. Quadriceps and triceps surae muscle volume was determined before and after bed rest and force and power were measured during training.

Differential expression of nitric oxide synthases (NOS 1-3) in human skeletal muscle following exercise countermeasure during 12 weeks of bed rest.

Adaptive changes of major body systems in astronauts during spaceflight can be simulated by strict anti-orthostatic head-down tilt (HDT) bed rest (BR), a ground-based microgravity (microG) model that provides a meaningful opportunity to study atrophy mechanisms and possible countermeasures under controlled experimental conditions. As nitric oxide (NO) signaling is linked to muscle activity, we investigated altered expression of the three major isoforms of nitric oxide synthase (NOS 1-3) at cellular compartments during prolonged HDT BR without (control group) and with resistance exercise interventions (exercise group) using a flywheel ergometer (FWE). Atrophy detected in mixed (fast-slow) m.