Are Changes in Thigh Muscle Concentric Strength Associated With Changes in Leg Function After a Youth Sport-Related Knee Injury?

Background: Assess the association between changes in injured leg knee extension and flexion strength (peak torque) and self-reported and performance-based measures of leg function after a variety of youth sport-related, time-loss knee injuries.

Hypothesis: There will be a relationship between changes in knee muscle strength and changes in measures of leg function in youth after a sport-related knee injury.

Study Design: Prospective cohort study.

Quadriceps Morphology 6- to 60-Months After Anterior Cruciate Ligament Tear.

The purpose of this study was to compare quadriceps morphology between legs and individuals with a first-time anterior cruciate ligament (ACL) tear and uninjured controls. This was an exploratory cross-sectional study. We enrolled participants who were aged 19-35 years, and 6-60 months after a first-time ACL tear as well as uninjured controls.

A Critical Occluding Tension Phase Transition Occurs Between 30% and 40% 1RM in Dynamic Knee Extension Exercise.

Oxygen delivery and utilization to working muscle(s) are essential for sustained exercise performance. Higher contractile loads can occlude intramuscular blood vessels, limiting oxygen perfusion, while lighter loads minimize occlusion and allow perfusion. This study explored how external load impacted relative muscle endurance, work capacity, and muscle oxygenation in free-flow and cuff-occluded states to estimate the load at which a muscle occludes itself.

Collagen remodeling increases after acute resistance exercise in healthy skeletal muscle irrespective of age.

Alterations to the extracellular matrix of skeletal muscle are implicated in age-related declines in muscle quality. Reduced collagen breakdown and collagen accumulation between muscle fibers are suggested to reduce the force-generating capacity of the muscle and impede adaptation to mechanical loading. The current study investigated total intramuscular collagen content in healthy, physical fitness-matched young and older skeletal muscle and how regulators of collagen breakdown respond to an acute bout of resistance exercise.

Turning over new ideas in human skeletal muscle proteostasis: What do we know and where to from here?

Understanding the turnover of proteins in tissues gives information as to how external stimuli result in phenotypic change. Nowhere is such phenotypic change more conspicuous than skeletal muscle, which can be effectively remodelled by increased loading, ageing and unloading (disuse), all of which are subject to modification by nutrition and other environmental stimuli. The understanding of muscle proteome remodelling has undergone a renaissance recently with the reintroduction of deuterated water (DO) and its ingestion to label amino acids and measure their incorporation into proteins.

Perspective on strategies for matching across age and sex in physiology research: "recreationally active" is not good enough.

Cardiorespiratory fitness (CRF) and muscular fitness are powerful confounders in age and sex-related comparisons. This paper provides a perspective on the benefits and limitations of matching participants by physical activity behaviour, objectively measured fitness and normative fitness percentiles. Data presented herein are a subset of a larger study, and highlight that matching by physical activity, does not necessarily match on other metrics like physical fitness, especially when age-related comparisons are being made.

Network-based modelling reveals cell-type enriched patterns of non-coding RNA regulation during human skeletal muscle remodelling.

A majority of human genes produce non-protein-coding RNA (ncRNA), and some have roles in development and disease. Neither ncRNA nor human skeletal muscle is ideally studied using short-read sequencing, so we used a customized RNA pipeline and network modelling to study cell-type specific ncRNA responses during muscle growth at scale. We completed five human resistance-training studies ( = 144 subjects), identifying 61% who successfully accrued muscle-mass.

Network-based modelling reveals cell-type enriched patterns of non-coding RNA regulation during human skeletal muscle remodelling.

A majority of human genes produce non-protein-coding RNA (ncRNA), and some have roles in development and disease. Neither ncRNA nor human skeletal muscle is ideally studied using short-read sequencing, so we used a customised RNA pipeline and network modelling to study cell-type specific ncRNA responses during muscle growth at scale. We completed five human resistance-training studies (n=144 subjects), identifying 61% who successfully accrued muscle-mass.

Validation of a bluetooth-enabled load cell for objective and accessible assessment of lower extremity strength.

High magnitude loading from performing resistance-based exercise has been found to improve tendon strength and reduce symptoms of Achilles tendinopathy (AT) but is difficult to quantify without specialist equipment. Here, we assess the validity and reliability of a novel AT rehabilitation tool (the "PhysViz" system) compared to a "gold-standard" dynamometer for assessing plantarflexion maximal voluntary isometric contractions (MVIC). 41 participants aged 18-60 completed the study.

Circulatory miRNAs as Correlates of Elevated Intra-Pancreatic Fat Deposition in a Mixed Ethnic Female Cohort: The TOFI_Asia Study.

Ectopic lipid accumulation, including intra-pancreatic fat deposition (IPFD), exacerbates type 2 diabetes risk in susceptible individuals. Dysregulated circulating microRNAs (miRNAs) have been identified as correlating with clinical measures of pancreatitis, pancreatic cancer and type 1 diabetes. The aim of the current study was therefore to examine the association between circulating abundances of candidate miRNAs, IPFD and liver fat deposition as quantified using magnetic resonance imaging (MRI) and spectroscopy (MRS).

Cold water immersion in recovery following a single bout resistance exercise suppresses mechanisms of miRNA nuclear export and maturation.

Cold water immersion (CWI) following intense exercise is a common athletic recovery practice. However, CWI impacts muscle adaptations to exercise training, with attenuated muscle hypertrophy and increased angiogenesis. Tissue temperature modulates the abundance of specific miRNA species and thus CWI may affect muscle adaptations via modulating miRNA expression following a bout of exercise.

Plasma metabolomic response to high-carbohydrate meals of differing glycaemic load in overweight women.

Background: Metabolomic dysregulation following a meal in overweight individuals with the Metabolic Syndrome (MetS) involves multiple pathways of nutrient storage and oxidation.

Objective: The aim of the current study was to perform an acute cross-over intervention to examine the interactive actions of meal glycaemic load (GL) on the dynamic responses of the plasma metabolome in overweight females.

Methods: Postmenopausal women [63 ± 1.

Minimal adaptation of the molecular regulators of mitochondrial dynamics in response to unilateral limb immobilisation and retraining in middle-aged men.

Purpose: Mitochondrial dynamics are regulated by the differing molecular pathways variously governing biogenesis, fission, fusion, and mitophagy. Adaptations in mitochondrial morphology are central in driving the improvements in mitochondrial bioenergetics following exercise training. However, there is a limited understanding of mitochondrial dynamics in response to inactivity.

Higher- and lower-load resistance exercise training induce load-specific local muscle endurance changes in young women: a randomised trial.

The effect of resistance training with higher- and lower-loads on muscle mass and strength has been extensively studied, while changes in muscle endurance have received less attention. This trial aimed to assess the effect of training load on absolute muscle endurance (AME) and relative muscle endurance (RME). Sixteen untrained women (22.

The Impact of Abdominal Body Contouring Surgery on Physical Function After Massive Weight Loss: A Pilot Prospective Matched Comparison.

Background: Many individuals develop excess skin (ES) following massive weight loss (MWL). Patient-reported outcomes demonstrate that abdominal ES negatively impacts perceived physical function which is improved by abdominal body contouring surgery (ABCS). However, the effect of ABCS on objective measures of physical function is unknown.

The Effect of Elevated Protein Intake on DNA Damage in Older People: Comparative Secondary Analysis of Two Randomized Controlled Trials.

A high protein intake at old age is important for muscle protein synthesis, however, this could also trigger protein oxidation with the potential risk for DNA damage. The aim of this study was to investigate whether an increased protein intake at recommended level or well above would affect DNA damage or change levels of reduced (GSH) and oxidised glutathione (GSSG) in community-dwelling elderly subjects. These analyses were performed in two randomized intervention studies, in Austria and in New Zealand.

Responsiveness of one-carbon metabolites to a high-protein diet in older men: Results from a 10-wk randomized controlled trial.

Objectives: Dietary strategies to promote successful aging are divergent. Higher-protein diets are recommended to preserve skeletal muscle mass and physical function. Conversely, increased B-vitamin intake, supporting one-carbon (1C) metabolism, reduces the risk of cognitive decline and cardiovascular disease.

Analysis of Human Faecal Host Proteins: Responsiveness to 10-Week Dietary Intervention Modifying Dietary Protein Intake in Elderly Males.

Faecal proteomics targeting biomarkers of immunity and inflammation have demonstrated clinical application for the identification of changes in gastrointestinal function. However, there are limited comprehensive analyses of the host faecal proteome and how it may be influenced by dietary factors. To examine this, the post-diet proteome of older males was analysed at the completion of a 10-week dietary intervention, either meeting the minimum dietary protein recommendations (RDA; = 9) or twice the recommended dietary allowance (2RDA, = 10).

MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis.

Healthy aging can be promoted by enhanced metabolic fitness and physical capacity. Mitochondria are chief metabolic organelles with strong implications in aging that also coordinate broad physiological functions, in part, using peptides that are encoded within their independent genome. However, mitochondrial-encoded factors that actively regulate aging are unknown.

Daily protein supplementation attenuates immobilization-induced blunting of postabsorptive muscle mTORC1 activation in middle-aged men.

Disuse-induced muscle atrophy is accompanied by a blunted postprandial response of the mammalian target of rapamycin complex 1 (mTORC1) pathway. Conflicting observations exist as to whether postabsorptive mTORC1 pathway activation is also blunted by disuse and plays a role in atrophy. It is unknown whether changes in habitual protein intake alter mTORC1 regulatory proteins and how they may contribute to the development of anabolic resistance.

Ribosome biogenesis and degradation regulate translational capacity during muscle disuse and reloading.

Background: Translational capacity (i.e. ribosomal mass) is a key determinant of protein synthesis and has been associated with skeletal muscle hypertrophy.

Molecular Transducers of Human Skeletal Muscle Remodeling under Different Loading States.

Loading of skeletal muscle changes the tissue phenotype reflecting altered metabolic and functional demands. In humans, heterogeneous adaptation to loading complicates the identification of the underpinning molecular regulators. A within-person differential loading and analysis strategy reduces heterogeneity for changes in muscle mass by ∼40% and uses a genome-wide transcriptome method that models each mRNA from coding exons and 3' and 5' untranslated regions (UTRs).

MitoQ and CoQ10 supplementation mildly suppresses skeletal muscle mitochondrial hydrogen peroxide levels without impacting mitochondrial function in middle-aged men.

Purpose: Excess production of reactive oxygen species (ROS) from the mitochondria can promote mitochondrial dysfunction and has been implicated in the development of a range of chronic diseases. As such there is interest in whether mitochondrial-targeted antioxidant supplementation can attenuate mitochondrial-associated oxidative stress. We investigated the effect of MitoQ and CoQ10 supplementation on oxidative stress and skeletal muscle mitochondrial ROS levels and function in healthy middle-aged men.

High-intensity interval exercise increases humanin, a mitochondrial encoded peptide, in the plasma and muscle of men.

Humanin is a small regulatory peptide encoded within the 16S ribosomal RNA gene () of the mitochondrial genome that has cellular cyto- and metabolo-protective properties similar to that of aerobic exercise training. Here we investigated whether acute high-intensity interval exercise or short-term high-intensity interval training (HIIT) impacted skeletal muscle and plasma humanin levels. Vastus lateralis muscle biopsies and plasma samples were collected from young healthy untrained men ( = 10, 24.