Exercise Intolerance in McArdle Disease: A Role for Cardiac Impairment? A Preliminary Study in Humans and Mice.

Introduction: Whether cardiac impairment can be fully discarded in McArdle disease-the paradigm of "exercise intolerance," caused by inherited deficiency of the skeletal muscle-specific glycogen phosphorylase isoform ("myophosphorylase")-remains to be determined.

Methods: Eight patients with McArdle disease and seven age/sex-matched controls performed a 15-min moderate, constant-load cycle-ergometer exercise bout followed by a maximal ramp test. Electrocardiographic and two-dimensional transthoracic (for cardiac dimension's assessment) and speckle tracking (for left ventricular global longitudinal strain (GLS) assessments) echocardiographic evaluations were performed at baseline.

Mental Health in Doctoral Students: Individual, Academic, and Organizational Predictors.

Background: The mental health of doctoral students is a matter of concern, and several variables appear to be associated with the state of their mental health. However, there have been no studies on the population of doctoral students in Spain to date using validated instruments.

Method: A cross-sectional observational study was conducted to assess mental health in 1,018 doctoral students.

Acute ketone supplementation in the absence of muscle glycogen utilization: Insights from McArdle disease.

Background & Aims: Ketone supplementation is gaining popularity. Yet, its effects on exercise performance when muscle glycogen cannot be used remain to be determined. McArdle disease can provide insight into this question, as these patients are unable to obtain energy from muscle glycogen, presenting a severely impaired physical capacity.

Fatigue and associated factors in 172 patients with McArdle disease: An international web-based survey.

McArdle disease is an autosomal recessive inherited disease caused by pathogenic variants in the PYGM gene, resulting in virtual absence of the myophosphorylase enzyme in skeletal muscle. Patients experience physical activity intolerance, muscle pain, and muscle fatigue. This study aimed to investigate other fatigue domains with the Multidimensional Fatigue Inventory (MFI-20) along with an investigation of potential contributing factors, including relevant disease and lifestyle-related factors.

Dose-response effect of pre-exercise carbohydrates under muscle glycogen unavailability: Insights from McArdle disease.

Background: This study aimed to determine the effect of different carbohydrate (CHO) doses on exercise capacity in patients with McArdle disease-the paradigm of "exercise intolerance", characterized by complete muscle glycogen unavailability-and to determine whether higher exogenous glucose levels affect metabolic responses at the McArdle muscle cell (in vitro) level.

Methods: Patients with McArdle disease (n = 8) and healthy controls (n = 9) underwent a 12-min submaximal cycling constant-load bout followed by a maximal ramp test 15 min after ingesting a non-caloric placebo. In a randomized, double-blinded, cross-over design, patients repeated the tests after consuming either 75 g or 150 g of CHO (glucose:fructose = 2:1).

The Effects of Melatonin Supplementation on Professional Football Player Performance: A Systematic Review.

Background: Melatonin is a hormone that has shown anti-inflammatory actions, reduced oxidative stress, and has effects on physical performance, so the aim of this study was to review the effects of melatonin supplementation on the performance of professional soccer players.

Methods: Critical and systematic review. Data were obtained by performing searches in the following bibliographic databases: Web of Science, MEDLINE (via PubMed), Embase, Cochrane Library, and Scopus.

High-intensity Actions in Elite Soccer: Current Status and Future Perspectives.

Over the years, soccer has become more physically demanding; the number and frequency of high-intensity actions have increased, and these activities are decisive in determining the match outcome. Importantly, the reductionist approach commonly used to analyze high-intensity actions does not contemplate a more contextualized perspective on soccer performance. Traditionally, most investigations have only provided quantitative data regarding sprints (i.

Patient-Reported Experiences with a Low-Carbohydrate Ketogenic Diet: An International Survey in Patients with McArdle Disease.

The low-carbohydrate ketogenic diet (LCKD) has attracted increased attention in recent years as a potential treatment option for individuals with McArdle disease (glycogen storage disease type V), and despite the absence of strong scientific evidence of the LCKD's benefits, increased numbers of individuals with McArdle disease have tried a LCKD. The objective of this study was to collect patient-reported experiences with a LCKD. We aimed to estimate the immediate prevalence of individuals that had tried a LCKD in an international McArdle disease cohort, and we aimed to report on the patient-reported experiences with the diet, both positive and negative.

Durability in Professional Cyclists: A Field Study.

Purpose: To assess durability in professional cyclists, as well as potential associated indicators.

Methods: Twelve male professional cyclists participated in the study (age: 26 [5] y, VO2max: 83.0 [3.

Low aerobic capacity in McArdle disease: A role for mitochondrial network impairment?

Background: McArdle disease is caused by myophosphorylase deficiency and results in complete inability for muscle glycogen breakdown. A hallmark of this condition is muscle oxidation impairment (e.g.

Muscle glycogen unavailability and fat oxidation rate during exercise: Insights from McArdle disease.

Carbohydrate availability affects fat metabolism during exercise; however, the effects of complete muscle glycogen unavailability on maximal fat oxidation (MFO) rate remain unknown. Our purpose was to examine the MFO rate in patients with McArdle disease, comprising an inherited condition caused by complete blockade of muscle glycogen metabolism, compared to healthy controls. Nine patients (three women, aged 36 ± 12 years) and 12 healthy controls (four women, aged 40 ± 13 years) were studied.

Influence of Tactical Behaviour on Running Performance in The Three Most Successful Soccer Teams During the Competitive Season of The Spanish First Division.

The purpose of this study was to analyze the influence of tactical behavior on physical performance of the three best Spanish soccer teams. Team 1 employed a 1-4-4-2 formation with compact defence and direct attacks, Team 2 employed an indirect style of play with a 1-4-3-3 formation and Team 3 used a 1-4-3-3 formation with elaborate attacks and strong counter-attacks. 816 individual situations of 54 professional soccer players categorized as fullbacks (FB), central defenders (CD), central midfielders (MF), wide midfielders (WM), and strikers (S) were included in the analysis.

External Workload Compared Between Competitive and Non-Competitive Matches for Professional Male Soccer Players.

The purpose of this study was to compare the external load in competitive (official) and non-competitive matches (friendly, training and modified-sided games) in professional soccer players. Time-motion data for 10 elite male soccer players (age = 20.1 ± 2.

Comparative analysis of endurance, strength and body composition indicators in professional, under-23 and junior cyclists.

To compare endurance, strength and body composition indicators between cyclists of three different competition age categories. Fifty-one male road cyclists classified as either junior ( = 13, age 16.4 ± 0.

Identification of Potential Muscle Biomarkers in McArdle Disease: Insights from Muscle Proteome Analysis.

Glycogen storage disease type V (GSDV, McArdle disease) is a rare genetic myopathy caused by deficiency of the muscle isoform of glycogen phosphorylase (PYGM). This results in a block in the use of muscle glycogen as an energetic substrate, with subsequent exercise intolerance. The pathobiology of GSDV is still not fully understood, especially with regard to some features such as persistent muscle damage (i.

Effect of ball inclusion on jump performance in soccer players: a biomechanical approach.

Objective: In soccer, vertical jump means jumping toward a ball. Since no vertical jump test includes the ball as a reference element, the effect that the ball would have in a vertical jump test is unknown. The aim of this study was to examine the biomechanical differences between run-up vertical jump measurements without (Run-up Vertical Jump) and with ball inclusion (Heading Test).

Long-Term Exercise Intervention in Patients with McArdle Disease: Clinical and Aerobic Fitness Benefits.

Introduction: The long-term effects of exercise in patients with McArdle disease-the paradigm of "exercise intolerance"-are unknown. This is an important question because the severity of the disease frequently increases with time.

Purpose: This study aimed to study the effects of a long-term exercise intervention on clinical and fitness-related outcomes in McArdle patients.

How does curve sprint evolve across different age categories in soccer players?

Research has shown that soccer players regularly execute curved sprints during matches. The purpose of this study was to determine the age-related effects on curve sprint (CS) performance to both sides, asymmetry, and association with linear sprint (LS). Eighty-four soccer players (aged 16.

Preclinical Research in McArdle Disease: A Review of Research Models and Therapeutic Strategies.

McArdle disease is an autosomal recessive disorder of muscle glycogen metabolism caused by pathogenic mutations in the gene, which encodes the skeletal muscle-specific isoform of glycogen phosphorylase. Clinical symptoms are mainly characterized by transient acute "crises" of early fatigue, myalgia and contractures, which can be accompanied by rhabdomyolysis. Owing to the difficulty of performing mechanistic studies in patients that often rely on invasive techniques, preclinical models have been used for decades, thereby contributing to gain insight into the pathophysiology and pathobiology of human diseases.

Reliability and usefulness of maximum soccer-specific jump test: a valid and cost-effective system to measure on soccer field.

The aims of this study were (a) to assess intra-session reliability and usefulness of the soccer-specific maximum vertical jump (heading test, HT) and (b) to analyse the validity of the easy-to-use and cost-effective instrument (smartphone camera, MOB) compared with gold-standard instrument (3D motion capture system, MOCAP) to obtain the vertical jump performance during HT. Twelve semi-professional high-level and fifteen amateur soccer male players (23.9 ± 3.

The Second Wind in McArdle Patients: Fitness Matters.

The "second wind" (SW) phenomenon-commonly referring to both an initial period of marked intolerance to dynamic exercise (e.g., brisk walking) that is not followed by perceived improvement and disappearance of previous tachycardia (i.

Long-Term Benefits of Tailored Exercise in Severe Sarcoidosis: A Case Report.

Background: We studied the effects of a supervised, structured exercise program in a severe sarcoidosis patient.

Methods: After being clinically stable for two years, a 52-year-old woman (stage IV, American Thoracic Society) who originally had irreversible lung fibrosis, pulmonary arterial hypertension (PAH), mild mitral insufficiency, and atrial dilatation, and was candidate for lung transplant, performed a combined high-intensity interval, high load resistance, and inspiratory muscle training for 4.5 years, and was tested (cardiopulmonary exercise testing and dual X-ray absorptiometry) every six months.

Data from the European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC).

Background: The European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC) was launched to register rare muscle glycogenoses in Europe, to facilitate recruitment for research trials and to learn about the phenotypes and disseminate knowledge about the diseases through workshops and websites. A network of twenty full and collaborating partners from eight European countries and the US contributed data on rare muscle glycogenosis in the EUROMAC registry. After approximately 3 years of data collection, the data in the registry was analysed.

Long-Term Combined Training in Idiopathic Pulmonary Fibrosis: A Case Study.

A supervised combined training program was applied to a sedentary 56-year-old man with idiopathic pulmonary fibrosis (IPF) along three years, until lung transplantation. It included: (a) aerobic continuous (CT) and interval training (IT), (b) high load resistance training (RT) and (c) inspiratory muscle training (IMT). IT and IMT were applied for two years, while CT and RT could be maintained until transplantation using supplemental oxygen.