Lactate and the GPR81 receptor in metabolic regulation: implications for adipose tissue function and fatty acid utilisation by muscle during exercise

Lactate is increasingly recognised to be more than a simple end product of anaerobic glycolysis. Skeletal muscle and white adipose tissue are considered to be the main sites of lactate production and release. Recent studies have demonstrated that there is a specific G-protein coupled receptor for lactate, GPR81, which is expressed primarily in adipose tissue, and also in muscle. Lactate inhibits lipolysis in adipose tissue by mediating, through GPR81, the anti-lipolytic action of insulin. A high proportion (50% or more) of the glucose utilised by white adipose tissue is converted to lactate and lactate production by the tissue increases markedly in obesity; this is likely to reflect a switch towards anaerobic metabolism with the development of hypoxia in the tissue. During exercise, there is a shift in fuel utilisation by muscle from lipid to carbohydrate, but this does not appear to be a result of the inhibition of lipolysis in the main adipose tissue depots by muscle-derived lactate. It is suggested instead that a putative autocrine lactate loop in myocytes may regulate fuel utilisation by muscle during exercise, operating via a muscle GPR81 receptor. In addition to being an important substrate, lactate is a key signal in metabolic regulation

The Effect of Glutamine in Modulating Exertional Heat Stress Response of Intestinal Cells in Trained and Untrained Runners

Glutamine is the preferred substrate of intestinal cells and is required for the protection of intestinal cells integrity, helping to prevent exercise-induced endotoxin leakage from the intestine during stressful conditions. Increased endotoxins in the blood circulation (also known as endotoxaemia) has been shown to trigger systemic inflammation which is implicated in exertional heat stroke. This study examined firstly whether orally administered glutamine helps to reduce intestinal injury following an acute high intensity exercise session in hot conditions and secondly whether there is a different outcome according to fitness levels in runners. A randomized, double-blinded crossover study design was utilized. Twelve runners unacclimatised to heat, divided into trained [T; n=6; maximal oxygen uptake (VO2max) = 61.2 ± 1.0 ml∙kg-1∙min-1] and untrained (UT; n=6; VO2max = 51.0 ± 0.7 ml∙kg-1∙min-1) groups, ingested either a placebo or glutamine dipeptide supplement (L-alanyl-L-glutamine; 0.2 g/kg bodyweight/day) for 5 consecutive days before running at 70%VO2max in a climate chamber (30°C, 40% relative humidity) for 1 hour. Cardiac output, stroke volume, heart rates, sweat loss, percent dehydration, rectal and skin surface temperatures were measured. Venous blood samples at baseline, immediately after completion of run and 1-hour post run were analysed for endotoxins and intestinal fatty acid binding proteins (I-FABP) as markers of intestinal injury. Intestinal permeability was measured at pre and post exercise using dual sugar probes (L-R; lactulose and rhamnose). No significant difference was observed in all responses for training status. L-R ratios remained unchanged with or without glutamine. However, a significant main effect for time and treatment was observed for plasma I-FABP (

Supporting placement supervision in clinical exercise physiology

The continued engagement of the professional workforce as supervisors is critical for the sustainability and growth of work-integrated learning activities in university degrees. This study investigated factors that influence the willingness and ability of clinicians to continue to supervise clinical exercise physiology work-integrated learning opportunities and makes recommendations for future supervision engagement. Themes identified from a supervisor survey were: staffing and time availability; administrative processes and support; student quality, knowledge and attitudes; student learning experiences; supporting the profession; service benefit; clinical personal benefit; funding; workplace support; staff qualifications and experience; prior positive experiences; future recruitment; facilities and infrastructure; and supporting the university. The responses resulted in five key recommendations for future enhanced and sustainable placement supervision. These were: adoption of efficient supervision structures; development and use of a competency checklist; enhanced recognition of supervision; standardized placement paperwork and assessment tools; and broadening of placement scheduling

Alpha-Actinin-3 (ACTN3) R/X Gene Polymorphism and Physical Performance of Multi-Ethnic Malaysian Population

A disparity population data set in the current literature with limited reports among Asian samples and the inconsistent findings among different ethnic groups warrant further investigation on the association between alpha-actinin-3 (ACTN3) R/X gene polymorphism and human physical performance in Asian population. This study was designed to examine the association between ACTN3 R/X gene polymorphism and physical performance of multi-ethnic Malaysian population. One hundred eighty well-trained athletes (34 endurance, 41 strength, and 105 intermittent) and 180 controls were drawn from four ethnic groups in Malaysia (Malay, Chinese, Indian, and Other Bumiputra). A sample of deoxyribonucleic acid (DNA) was retrieved from a buccal swab from each participant and the ACTN3 R/X genotype was identified through polymerase chain reaction and restriction fragment length polymorphism analysis. The strength and endurance performances of the athletes were evaluated with maximal voluntary contraction and Yo-Yo intermittent recovery level 2 tests, respectively. The independent t-test, chi-square, multivariate, and one-way analysis of variance were used for data analysis. ACTN3 R/X alleles (p = 0.672) and genotype (p = 0.355) frequencies did not vary much between the multi-ethnic groups of Malaysian athletes. These small variations did not have any influence on handgrip strength (p = 0.334), leg strength (p = 0.256), and Yo-Yo intermittent recovery level 2 performance (p = 0.425) between these ethnic groups. The RR and XX genotypes were more frequent among strength and intermittent athletes, respectively. Athletes with the RR genotype had greater handgrip than those with the RX genotype (p = 0.031), but not different from athletes with the XX genotype (p = 0.228)

Determination of clinical competencies for exercise physiology students

Introduction: Clinical placements and assessment are a key part of health professional education. However, quality assessment in a clinical environment is difficult to achieve without a clear picture of what constitutes competence. The aim of this study was to establish a set of competencies that describe the attributes considered critical to ensuring an entry-level exercise physiologist (EP) can practice safely and effectively with a client-centred philosophy. Methods: This study used a mixed methods, multiphase approach. The competencies, which are organised into units of competency with underlying elements, were developed following online surveys and focus groups involving those with expertise in the area, with additional refinement provided by the project team. A first-stage validation was conducted via electronic survey where (i) participants rated the importance of each unit of competency to practice as an entry-level EP; and (ii) those participants who were recently graduated EPs rated the extent to which they perceived they were competent in each unit. Results: The final set of competencies is described as 19 elements organised into 6 units. The units are: (i) Communication, (ii) Professionalism, (iii) Assessment and Interpretation, (iv) Planning and delivery of an exercise and/or physical activity intervention, (v) Lifestyle Modification and (vi) Risk Management. The majority of survey participants (93-97%) considered each unit of competency as being important to practice successfully as an entry-level EP. The majority (78-95%) of the sub-group who identified as new EPs considered themselves competent in each unit, suggesting the competencies are articulated at the level of a new EP. Conclusion: The competencies resulted from an extensive, iterative process involving those with expertise in the area followed by initial validation. The competencies will have a range of applications, including informing the development of a student placement assessment tool

Determination of clinical competencies for exercise physiology students

Introduction: Clinical placements and assessment are a key part of health professional education. However, quality assessment in a clinical environment is difficult to achieve without a clear picture of what constitutes competence. The aim of this study was to establish a set of competencies that describe the attributes considered critical to ensuring an entry-level exercise physiologist (EP) can practice safely and effectively with a client-centred philosophy. Methods: This study used a mixed methods, multiphase approach. The competencies, which are organised into units of competency with underlying elements, were developed following online surveys and focus groups involving those with expertise in the area, with additional refinement provided by the project team. A first-stage validation was conducted via electronic survey where (i) participants rated the importance of each unit of competency to practice as an entry-level EP; and (ii) those participants who were recently graduated EPs rated the extent to which they perceived they were competent in each unit. Results: The final set of competencies is described as 19 elements organised into 6 units. The units are: (i) Communication, (ii) Professionalism, (iii) Assessment and Interpretation, (iv) Planning and delivery of an exercise and/or physical activity intervention, (v) Lifestyle Modification and (vi) Risk Management. The majority of survey participants (93-97%) considered each unit of competency as being important to practice successfully as an entry-level EP. The majority (78-95%) of the sub-group who identified as new EPs considered themselves competent in each unit, suggesting the competencies are articulated at the level of a new EP. Conclusion: The competencies resulted from an extensive, iterative process involving those with expertise in the area followed by initial validation. The competencies will have a range of applications, including informing the development of a student placement assessment tool

Reductions in C-reactive protein in older adults with type 2 diabetes are related to improvements in body composition following a randomized controlled trial of resistance training

BACKGROUND: Reductions in skeletal muscle mass and increased adiposity are key elements in the aging process and in the pathophysiology of several chronic diseases. Systemic low grade inflammation associated with obesity has been shown to accelerate the age-related decline in skeletal muscle. The aim of this investigation was to determine the effects of 12 months of progressive resistance training (PRT) on systemic inflammation, and whether reductions in systemic inflammation were associated with changes in body composition. We hypothesized that reductions in systemic inflammation following 12 months of PRT in older adults with type 2 diabetes would be associated with reductions in adiposity and increases in skeletal muscle mass. METHODS: Participants (n = 103) were randomized to receive either PRT or sham-exercise, 3 days a week for 12 months. C-reactive protein (CRP) was used to assess systemic inflammation. Skeletal muscle mass and total fat mass were determined using bioelectrical impedance. RESULTS: Twelve months of PRT tended to reduce CRP compared to sham exercise (β = −0.25, p = 0.087). Using linear mixed-effects models, the hypothesized relationships between body composition adaptations and CRP changes were significantly stronger for skeletal muscle mass (p = 0.04) and tended to be stronger for total fat mass (p = 0.07) following PRT when compared to sham-exercise. Using univariate regression models, stratified by group allocation, reductions in CRP were associated with increases in skeletal muscle mass (p = 0.01) and reductions in total fat mass (p = 0.02) in the PRT group, but not in the sham-exercise group (p = 0.87 and p = 0.32, respectively). CONCLUSIONS: We have shown for the first time that reductions in systemic inflammation in older adults with type 2 diabetes following PRT were associated with increases in skeletal muscle mass. Furthermore, reductions in CRP were associated with reductions in adiposity, but only when associated with PRT. Lifestyle interventions aimed at reducing systemic inflammation in older adults with type 2 diabetes should therefore incorporate anabolic exercise such as PRT to optimize the anti-inflammatory benefits of favorable body composition adaptations

Reporting animal research:Explanation and elaboration for the ARRIVE guidelines 2.0

Improving the reproducibility of biomedical research is a major challenge. Transparent and accurate reporting is vital to this process; it allows readers to assess the reliability of the findings and repeat or build upon the work of other researchers. The ARRIVE guidelines (Animal Research: Reporting In Vivo Experiments) were developed in 2010 to help authors and journals identify the minimum information necessary to report in publications describing in vivo experiments. Despite widespread endorsement by the scientific community, the impact of ARRIVE on the transparency of reporting in animal research publications has been limited. We have revised the ARRIVE guidelines to update them and facilitate their use in practice. The revised guidelines are published alongside this paper. This explanation and elaboration document was developed as part of the revision. It provides further information about each of the 21 items in ARRIVE 2.0, including the rationale and supporting evidence for their inclusion in the guidelines, elaboration of details to report, and examples of good reporting from the published literature. This document also covers advice and best practice in the design and conduct of animal studies to support researchers in improving standards from the start of the experimental design process through to publication