Metabolic Load Research Articles

Use of GPS to measure external load and estimate the incidence of muscle injuries in men's football: A novel descriptive study.

Measurement of external load in players provides objective information to optimise the weekly balance between training and recovery to improve performance and prevent injuries. Our aim was to evaluate the incidence of sports-related muscle injuries of the lower limb in relation to external load, measured by global positioning system (GPS), in football players. A descriptive study was carried out. Data were collected from 71 professional male football players (30 professionals and 41 youth players) from an elite football club competing in the Spanish and European League in the 2017-2018 season. As external load variables, we measured High Metabolic Load Distance (HMLD), High Speed Running (HSR), Player Load (PL), and Total Distance (TD) through GPS. Injury rate (IR) was calculated both in relation to such GPS load metrics and to load exposure time. We considered categories (youth and professional), playing positions (centre back, full back, midfielder, and forward), and training day with respect to match-day (-4MD, -3MD, -2MD, -1MD, MD, +1MD, +2MD). The GPS load metrics HMLD, HSR, PL, and TD showed very similar patterns across categories and positions, but varied according to training session or MD. The highest loads were observed on MD and three days prior to the match (-3MD). Similarly, the overall IR, both calculated per load exposure time and per GPS load metrics, was highest on MD and -3MD. Again, no differences were observed between youth and professional players. Midfielders demonstrated the highest IR in all metrics, followed by the forwards. In conclusion, this study suggests that external load and incidence of muscle injuries are directly proportional. Therefore, the measurement of more external load variables other than load exposure time, such as the GPS metrics HMLD, HSR, PL, and TD may help to describe the pattern and magnitude of injuries. Future studies based on ours may help to further improve the understanding of the incidence of muscle injuries on the basis of external loads measurements in different football teams.

Variations on Ernsting's Post-Decompression Hypoxia Prevention Model.

INTRODUCTION: In the event of decompression using an isobaric differential cockpit pressurization system, oxygen concentration breathed pre-decompression must be greater than required for the given cockpit altitude in order to prevent hypoxia. The model for determining oxygen concentration requirements advanced by Dr. John Ernsting, when graphed against cockpit altitude, creates a hypoxia safety "notch" which has become a standard requirement for aircraft oxygen systems. Although variables in the Ernsting notch model are not fixed, they are often presented as such.METHODS: Model equations are presented to evaluate the effects of different cockpit pressurization, oxygen regulator PBA schedules, and changes to the physiological state of the aircrew.RESULTS: Increased cockpit differential pressure, regulator breathing pressure, and aircrew respiratory quotient decreased pre-decompression oxygen concentration requirements by up to 6%, eliminating the hypoxia safety "notch." Although effects were small, reducing alveolar carbon dioxide pressure decreased oxygen concentration requirements while reducing respiratory quotient increased oxygen concentration requirements. A 10-mmHg increase in the minimal oxygen hypoxia threshold increased the pre-decompression oxygen concentration requirement 8 to 12% depending on cockpit altitude.CONCLUSION: Variation in cockpit and regulator pressure schedules which stray outside the parameters used by Ernsting need to be independently calculated. During flight, an individual's physiological "notch" will be dynamic, wavering in response to changes in metabolic load, respiratory dynamics, and environmental conditions. Consideration of aircrew activity should be factored in when considering minimal oxygen concentration for pre-decompression hypoxia protection in the design of aircrew life support systems.Dart TS, Morse BG. Variations on Ernsting's post-decompression hypoxia prevention model. Aerosp Med Hum Perform. 2022; 93(2):99-105.

The content and load of preseason field-based training in a championship-winning professional rugby league team: A case study

This study reports on the content and periodisation of the preseason field-based training for a professional rugby league team. Thirty professional male rugby league players (26 ± 5 years, 180.9 ± 6.5 cm, 94 ± 9 kg) completed an 8-week preseason. Global positioning system devices and heart rate were used to monitor physical and physiological responses of different field-based training components (speed, conditioning, rugby skill and game-based training). Rugby skill training contributed the most to the total distance covered, conditioning was the greatest contributor to high-speed running (>15 km/h) and game-based training provided the greatest high metabolic distance (>20 W/kg) and overall external load. Game-based training provided the greatest time with heart rate ≥80% estimated maximum. The weekly preseason cycle had lower loads on Monday and Thursday whereas Tuesday and Friday produced the highest loads. The preseason described herein adopted a progressive overload comprising a weekly undulating cycle. This study emphasises how skill and games-based training contributes significantly to the overall load of a professional rugby league team's preseason with more traditional conditioning promoting high-speed running load and high metabolic load.

Effect of training day, match, and length of the microcycle on workload periodization in professional soccer players: a full-season study.

The aims of this study were to: (a) describe and compare the volume and intensity from the workload of professional soccer players between training and MD, and (b) analyse the effect that the length of the microcycle had on the workload. A cohort study was designed for a full season in La Liga 123. Wearable tracking systems collected the distance covered in meters (m), total number of high-intensity accelerations (ACCHIGH) and decelerations (DECHIGH), total number of high-speed running actions (HSRA), high-speed running distance (HSRD), high metabolic load distance (HMLD), and player load (PL) from training days (MD+1, MD-4, MD-3, MD-2, and MD-1) and MD. Significant differences were found between training and MD workload, MD workload being the most demanding for all intensity and volume variables (F = 36.35–753.94; p < 0.01; wp2 = 0.21–0.85). The greatest training intensity and volume were found on MD-4 and MD-3 (p < 0.05). In addition, a novel finding was that the length of the microcycle had a significant effect on the workload both in volume and intensity (F = 4.84–14.19; p < 0.01; wp2 = 0.03–0.09), except for relative ACCHIGH, DECHIGH, and HMLD. Although MD-4 and MD-3 were the most suitable days for loading the players, the results showed that MD elicited a unique stimulus in terms of volume and intensity. Consequently, coaches need to include specific training drills to adapt the players for the competitive demands. Finally, special focus should be placed on MD from short and regular microcycles (5-day, 6-day, or 7-day microcycles) since declines in physical performance were observed in comparison with long microcycles (8-day or 9-day microcycles).

Isolation of Autophagy Competent Lysosomes from Cancer Cells by Differential Large-Scale Multilayered Density Gradient Centrifugations.

Accurate isolation of functional and intact lysosomes enables the quantification and analyses of abundances, dynamic changes and enrichment levels of lysosomal content, allowing specific lysosomal investigations induced by autophagy. In this protocol chapter, we describe detailed practical instructions and advices for an efficacious lysosomal enrichment and isolation procedure by differential multilayered density gradient centrifugations using human cancer cell lines. By this method, intact and autophagy competent lysosomes can be isolated from cancer cells based on their distinct density and obtained fractions can further be analyzed for functional lysosomal assays, as well as for protein or metabolic loads to identify select spatiotemporal changes by comparative quantitative measurement. This method has been used to enrich lysosomes from a variety of cancer cells with activated chaperone-mediated autophagy, but can be optimized for other cell lines and tissues for multiple autophagy-induced conditions.

Plasma Exchange Is an Effective Adjunct in the Management of Hyperbilirubinemia in Early Allograft Dysfunction and Small for Size Syndrome after Liver Transplant

Background: Management of early allograft dysfunction (EAD) and small for size syndrome (SFSS) after liver transplant remains challenging and care is largely based around supportive treatment. The role of plasmapheresis/plasma exchange in SFSS is not well established. However, it can potentially serve an important role as a salvage option by reducing the metabolic load of toxins including bilirubin and supplying important coagulation proteins to maintain coagulation homeostasis. Methods: We present three cases. A 19-year-old female underwent living-donor liver transplant (LDLT) and received a healthy right lobe graft. Graft-to-recipient weight ratio (GRWR) was 0.85. She developed SFSS and underwent one cycle of plasma exchange on post-operative day (POD) 8 (peak bilirubin 414umol/l) that was prematurely terminated as she developed an allergic response. A 58-year-old female underwent deceased-donor liver transplant and developed acute worsening hyperbilirubinemia on POD8-10 (from 116umol/l to 858 umol/l). She underwent one cycle of plasma exchange that was sufficient to serve as a bridge to treat the hyperbilirubinemia until liver biopsy diagnosis of acute cellular rejection was obtained and definitive steroid treatment was initiated. A 42-year-old female underwent LDLT and received a left lobe graft (GRWR 0.75). She developed SFSS despite portal inflow modulation performed during transplant. She underwent three sessions of plasma exchange (POD25,27,30). Results: In the three cases bilirubin levels improved significantly following plasma exchange, and graft recovery was evident. Conclusion: Our cases suggest the efficacy of plasma exchange as a potential adjunct for the supportive treatment of hyperbilirubinemia in EAD and SFSS to avoid re-transplantation.

Influence of the COVID-19 lockdown on Spanish professional soccer teams' external demands according to their on-field ranking.

The main objective of this study was to analyse the changes in external demand parameters (e.g., total distance, high-speed running distance, accelerations/decelerations) in Spanish professional soccer teams after the COVID-19 lockdown considering their on-field ranking (i.e., teams whose ranking worsened after the COVID-19 lockdown [WRS] vs. teams that improved their ranking after the COVID-19 lockdown [IMP]). A total of 23,527 individual match observations were collected on players competing during the 2019/20 season in the First Spanish Professional soccer League (LaLiga). Goalkeepers and players who participated for less than 10 minutes in each match were excluded. Relative total distance (TD/min), distance covered at 21–24 km · h-1 (HIRD/min) and > 24 km · h-1 per minute (VHIRD/min), high metabolic load distance (HMLD), and the number of accelerations (3 m/s2) and decelerations (< 3 m/s2) performed were analysed by the ChryonHego video-tracking system. These variables were analysed during two differentiated periods, before the COVID-19 lockdown (i.e., 27 matches) and after the COVID-19 lockdown (i.e., 11 matches), and teams were classified into two groups according to their ranking (i.e., WRS vs. IMP). R-Studio was employed for data analysis and a mixed linear model was conducted. A decrease in external demands in all teams after the COVID-19 lockdown was observed, and this decrease was greater in WRS. These results suggest that, after an inactive period (i.e., the COVID-19 lockdown), teams that return with better physical performance, mainly related to high-intensity actions, have more possibilities of improving their final qualifying position.

The effect of China's compulsory education reforms on physiological health in adulthood: a natural experiment.

Lower education is related to higher biological risks for physiological health, but it remains unclear whether the risks can be reduced through policies aimed at increasing years of education. We utilized China's compulsory education reforms as a unique natural experiment, which stipulates that primary and lower secondary education is mandatory and free for all school-age children. Using a regression discontinuity design (RDD), we assessed the effect of the reform eligibility on biomarkers. The reforms resulted in an increase in years of education for those from communities with the middle 1/3 per capita income (PCI) (β = 2.44, 95% CI = 0.23-4.64). Reform eligibility had no impact on allostatic risks for the total sample (β = 0.065, 95% CI = -0.70 to 0.83) and for those from communities with the lowest (β = 0.35, 95% CI = -0.77 to 1.47) or highest third of PCI (β = 0.68, 95% CI = -0.64 to 2.00), while it reduced the metabolic risk (β = -0.14, 95% CI = -0.26 to -0.015) and total allostatic load (β = -1.58, 95% CI = -3.00 to -0.16) among those from communities with the middle third PCI. The results were confirmed by sensitivity analyses of different placebo cut-off points and bandwidths. The reforms led to better physiological health to some extent, but the effect only manifested in people from communities with a moderate community PCI, and had little impact on affluent or disadvantaged groups. Our findings stressed that the institutional context and respondents' socioeconomic environment must be taken into account when assessing the health impact of China's compulsory education reforms.

782 Cardiopulmonary exercise testing in patients with COVID-19 at 3 months from hospital discharge

AimsThe long-term COVID-19 effects are currently unknown. Whether and for how long symptoms extend beyond the acute phase of the disease is unresolved. Aim of this study was to determine the functional capacity of COVID-19 survivors by cardiopulmonary exercise testing (CPET) and describe its association with dyspnoea, the most frequent symptom after discharge from a tertiary care hospital.Methods and resultsAll COVID-19 patients discharged from our tertiary care institution were enrolled in a prospective follow-up study which would assess clinical, instrumental and laboratory characteristics of COVID-19 survivors at 3 months from hospital discharge (i.e. long-covid). To limit bias in dyspnoea quantification, patients hospitalized in residential care facilities with severe cognitive impairment/disability, ischaemic cardiopathy, and/or heart failure and severe respiratory disease (i.e. chronic obstructive pulmonary disease) were excluded. Clinical evaluation included: peripheral blood samples including inflammatory cytokines, pulmonary function testing (functional respiratory and 6 min-walking test), lung ultrasound, ECG recording, and a comprehensive echocardiographic exam. All patients with peripheral oxygen desaturation at 6 min-walking test (SpO2 < 92%), dyspnoea and with a history of hospitalization in critical care settings were referred for CPET. Dyspnoea was classified with the Medical Research Council (MRC) scale. From June 2020 to May 2021, 198 patients were enrolled; overall, 42% of patients presented with dyspnoea at 3 months from hospital discharge with no difference according to disease severity on hospital admission (P = 0.233). Clinical, laboratory, and echocardiographic parameters were similar between patients with and without dyspnoea. At CPET, 61% of patients complaining dyspnoea showed a %peak VO2 lower than 85% of the predicted value, associated with a lower exercising tolerance and duration and with a globally reduced equivalent metabolic load (METS: 5.3 ± 1.2 vs. 6.6 ± 1.6, P = 0.003). Mean anaerobic threshold was lower for symptomatic patients (46 + 13 vs. 50 + 10, P = 0.03). At multivariable logistic regression analysis, after adjustment for age, number of comorbidities, and body mass index, only %peak VO2 (HR: 0.973; 95% CI: 0.948–0.998) and male gender (HR: 0.548; 95% CI: 0.328–0.999) were associated with dyspnoea.ConclusionsAt 3-months, almost 1-in-2 patients discharged for COVID-19 pneumonia presented with dyspnoea, irrespective of disease severity. Among patients undergoing CPET, only %peak VO2 and gender were associated with symptoms suggesting a potential systemic inflammatory-mediated response and important gender related differences for the long-covid.

Changes in milk ketone and fatty acid concentrations during early lactation in Holstein and Fleckvieh cows

The aim of this study was to compare the changes in milk composition postpartum, especially ketones and milk fatty acids (FAs), in Holstein and Fleckvieh cows kept under identical management conditions. Milk composite samples were collected from 66 cows during afternoon milking, at weekly intervals from one to eight weeks postpartum, and their components were determined by Fourier transform infrared spectroscopy. The Holstein cows had higher (P &amp;lt; 0.05) concentrations of long-chain FAs (ranging from 6% to 16% in different weeks), monounsaturated FAs (6% to 12%), and C18:1 (5% to 16%), as well as lower (P &amp;lt; 0.05) concentrations of saturated FAs (3% to 8%) and short-chain FAs (7% to 17%) in their milk than the Fleckvieh cows for almost the entire monitored period. These differences can be explained by pronounced lipomobilization, due to a negative energy balance, when mainly long-chain FAs from adipose tissue are incorporated into milk and significantly inhibit the de novo synthesis of FAs in the mammary gland. In conclusion, it can be assumed that breed-related metabolic changes during the first weeks of lactation have a large effect on the milk FA composition. This reflection of the metabolic load changes and lipomobilization in differing milk FA profiles would allow for the use of selected milk FAs to detect energy imbalances and their associated diseases in early lactation cows.

Characterizing Marathon-Induced Metabolic Changes Using 1H-NMR Metabolomics.

Although physical activity is a health-promoting, popular global pastime, regular engagement in strenuous exercises, such as long-distance endurance running races, has been associated with a variety of detrimental physiological and immunological health effects. The resulting altered physiological state has previously been associated with fluctuations in various key metabolite concentrations; however, limited literature exists pertaining to the global/holistic metabolic changes that are induced by such. This investigation subsequently aims at elucidating the metabolic changes induced by a marathon by employing an untargeted proton nuclear magnetic resonance (1H-NMR) spectrometry metabolomics approach. A principal component analysis (PCA) plot revealed a natural differentiation between pre- and post-marathon metabolic profiles of the 30-athlete cohort, where 17 metabolite fluctuations were deemed to be statistically significant. These included reduced concentrations of various amino acids (AA) along with elevated concentrations of ketone bodies, glycolysis, tricarboxylic acid (TCA) cycle, and AA catabolism intermediates. Moreover, elevated concentrations of creatinine and creatine in the post-marathon group supports previous findings of marathon-induced muscle damage. Collectively, the results of this investigation characterize the strenuous metabolic load induced by a marathon and the consequential regulation of main energy-producing pathways to accommodate this, and a better description of the cause of the physiological changes seen after the completion of a marathon.

Hypoxic and Hyperoxic Breathing as a Complement to Low-Intensity Physical Exercise Programs: A Proof-of-Principle Study.

Inflammation is an adaptive response to both external and internal stimuli including infection, trauma, surgery, ischemia-reperfusion, or malignancy. A number of studies indicate that physical activity is an effective means of reducing acute systemic and low-level inflammation occurring in different pathological conditions and in the recovery phase after disease. As a proof-of-principle, we hypothesized that low-intensity workout performed under modified oxygen supply would elicit a “metabolic exercise” inducing a hormetic response, increasing the metabolic load and oxidative stress with the same overall effect expected after a higher intensity or charge exercise. Herein, we report the effect of a 5-week low-intensity, non-training, exercise program in a group of young healthy subjects in combination with the exposure to hyperoxia (30% and 100% pO2, respectively) or light hypoxia (15% pO2) during workout sessions on several inflammation and oxidative stress parameters, namely hemoglobin (Hb), redox state, nitric oxide metabolite (NOx), inducible nitric oxide synthase (iNOS), inflammatory cytokine expression (TNF-α, interleukin (IL)-6, IL-10), and renal functional biomarkers (creatinine, neopterin, and urates). We confirmed our previous reports demonstrating that intermittent hyperoxia induces the normobaric oxygen paradox (NOP), a response overlapping the exposure to hypoxia. Our data also suggest that the administration of modified air composition is an expedient complement to a light physical exercise program to achieve a significant modulation of inflammatory and immune parameters, including cytokines expression, iNOS activity, and oxidative stress parameters. This strategy can be of pivotal interest in all those conditions characterized by the inability to achieve a sufficient workload intensity, such as severe cardiovascular alterations and articular injuries failing to effectively gain a significant improvement of physical capacity.

Weekly Variations of Short-Duration Maximal Jumping Performance in Soccer Players: Exploring Relationships With Accumulated Training Load and Match Demands.

Purpose: The aim of this study was 2-fold: (1) to analyze variations of short-duration maximal jumping performance in players exposed to a match and those who were not and (2) to analyze the relationships between changes in the short-duration maximal jumping performance and different accumulated training load and match demands measures.Methods: Twenty-four professional soccer players (age: 20.3 ± 1.7 years) were monitored daily for their training load and match demands over 6 weeks. In addition, they performed a weekly short-duration maximal jumping performance test (72 h after the last match).Results: Negative moderate correlations were found between percentage of change of countermovement jump (CMJ) height and Acummulated training load (ATL) of total distance (TD), high metabolic load (HML), accelerations (ACC), and decelerations (DEC) (r = −0.38, p = 0.004; r = −0.33, p = 0.013; r = −0.39, p = 0.003; and r = −0.30, p = 0.026). No correlations were found for match load (ML). TD, HML, ACC, and DCC (r = 0.27, r = 0.25, r = 0.31, and r = 0.22, respectively) were used to predict the percentage of change of CMJ height.Conclusion: Match participation has negative effects on CMJ performance. The ATL of HML, ACC, DCC, and TD have a significant influence on both CMJ measures changes. Also, the ATL values of those metrics are the best predictors of the percentage changes of CMJ performance.

Metabolic flexibility during normal pregnancy allows appropriate adaptation during gestation independently of BMI.

Overweight and obesity in reproductive-age women hasten the development of insulin resistance and increase risk for deterioration of pregnancy metabolism. These pregnancy-associated metabolic changes are similar to those of the metabolic syndrome. Thus, some metabolic flexibility must allow appropriate adaptation to the metabolic load that pregnancy imposes. We evaluated metabolic flexibility during uncomplicated pregnancy in women with pre-gestational normal weight or overweight. In 20 women with singleton pregnancies, pre-pregnancy BMI was categorized as normal-weight (Nw) or overweight (Ow). The women were seen quarterly, and fasting and postprandial blood samples were collected at each visit. Indirect fasting and/postprandial calorimetry was performed to evaluate metabolic flexibility (Δrespiratory quotient (RQ)=RQpostprandial - RQfasting). In the first trimester, metabolic flexibility was lower in the Ow group compared to the Nw group (0.031±0.0131 vs 0.077±0.018, respectively) without a statistically significant difference (p=0.053). In the second trimester, the Ow group was significantly more flexible than the Nw group (0.190±0.016 vs 0.077±0.015, respectively (p=0.004)). For the third trimester, the Ow and Nw groups did not differ in metabolic flexibility (0.074±0.013 vs 0.087±0.021, respectively) (p=0.40). The most influential variables for metabolic flexibility during pregnancy were lactate, leptin, β-hydroxybutyrate, glycerol, aromatic amino acids, medium and long chain acylcarnitine's. Our findings indicate that metabolic flexibility changes throughout pregnancy, independently of pre-pregnancy BMI. These changes maintain metabolic homeostasis between the mother and foetus, allowing for appropriate adjustments during pregnancy.

Training Load in Different Age Category Soccer Players and Relationship to Different Pitch Size Small-Sided Games.

This study sought to evaluate the training load in different age category soccer players associated with distinct pitch size small-sided games (SSGs). Twenty-four soccer players (eight in each age category: U-12, U-15, and U-23) performed three consecutive 4 vs. 4 ball possession SSGs (SSG1: 16 × 24 m; SSG2: 20 × 30 m; and SSG3: 24 × 36 m) all with 3 min duration and 3 min rest. Subjects carried ultra-wideband-based position-tracking system devices (WIMU PRO, RealTrack System). Total distance covered increased from SSG1 to SSG3 in all age categories and predominantly in running speeds below 12 km·h−1. Moreover, distance covered in 12–18 km·h−1 running speed was different in all performed SSGs and age categories. Residual or null values were observed at 18–21 km·h−1 or above running speed, namely in U-12, the only age category where metabolic power and high metabolic load distance differences occurred throughout the performed SSGs. Edwards’ TRIMP differences between age categories was only observed in SSG2 (U-12 < U-15). The design of SSGs must consider that the training load of the players differs according to their age category and metabolic assessment should be considered in parallel to external load evaluation in SSGs. Wearable technology represents a fundamental support in soccer.

Heart failure with preserved ejection fraction – new elements of evidence in the field of pathophysiology and new treatment options

Consistent with the understanding of the comorbidity-infl ammation relationship, concomitant diseases and especially metabolic comorbidities are thought to stimulate the development and severity of heart failure with preserved ejection fraction through a cascade of mechanisms supporting systemic tissue infl ammation leading to myocardial fi brosis. Recently, new experimental and clinical evidence has emerged that enhances validity and verifi es the infl ammatory-profi brotic paradigm. This evidence consists of: (1) myocardial infi ltration with immunocompetent cells not only due to metabolic load caused by obesity but also due to arterial hypertension-induced haemodynamic loading of extracellular matrix components (such as basal laminatin interacting with basal laminate); (2) expression in cardiomyocytes of inducible nitric oxide synthetase under the infl uence of circulating proinfl ammatory cytokines, which leads to accumulation of degraded proteins in the myocardium due to an unfolded protein response; (3) defi ning phenogroups of patients with heart failure with preserved ejection fraction with a distinct infl ammatory and profi brotic component by machining algorithms; (4) direct association. in mediation analysis between comorbidities, infl ammatory biomarkers and impaired myocardial structure and function with endothelial expression of adhesion molecules already accumulated in early preclinical heart failure with preserved ejection fraction (CH stage A, B). This new evidence paves the way for future treatment of heart failure with a conserved ejection fraction with biologics directed against 1) infl ammatory cytokines, 2) stimulating the development of a complete protein response and non-accumulation of protein in the chiocardia by phosphodiesterase inhibitors 1) the rigidity of titin by natriuretic peptide – the particular guanylyl cyclase – PDE9 (phosphodiesterase 9) and 4) molecular and cellular regulatory mechanisms that control myocardial fi brosis.

Physiological Correlation between Hypothalamic-Pituitary-Adrenal Axis, Leptin, UCP1 and Lipid Panel in Mares during Late Pregnancy and Early Postpartum Period.

Simple SummarySeveral features of periparturient mares’ physiology have been investigated; however, the possible linkage between HPA axis, leptin, and lipid metabolism in periparturient mares has received little attention. Therefore, the present study aimed to investigate the dynamic changes of adrenocorticotrophic hormone, cortisol, leptin, UCP1, lipids and liproteins levels in mares during late pregnancy and the postpartum period. The findings obtained in the current survey showed a dynamic modulation of studied parameters, namely the response to hormonal and metabolic adaptations, occurring during the peripartum period in mares. This study suggests an interaction of the HPA axis with lipid metabolism in mares, probably to deal with the metabolic load occurring during pregnancy and with lactation energy supplies.This study aimed to investigate the dynamic change of adrenocorticotrophic hormone (ACTH), cortisol, leptin, mitochondrial uncoupling protein 1 (UCP1), lipids and lipoproteins in mares during late pregnancy and the postpartum period. A total of 20 mares (10 pregnant mares, monitored from 14 ± 2 days before expected foaling until 14 days after foaling, Group A; 10 non-pregnant and non-lactating mares, Group B) were enrolled in the study. Body Condition Score (BCS) and body weight (BW) values were recorded from each animal. In Group A, blood samples were collected on days 14 ± 2 and 7 ± 2 before foaling (T−14; T−7), and on days 7 and 14 after foaling (T+7; T+14). From mares of Group B, blood samples were collected at the beginning of the study. The levels of ACTH, cortisol, leptin, UCP1, non-esterified fatty acids (NEFAs), total cholesterol, high-density lipoproteins (HDLs), low-density lipoproteins (LDLs), triglycerides and very-low-density lipoproteins (VLDLs) were investigated. While BCS showed no statistical change throughout the monitoring period (p > 0.05), all the other studied parameters displayed statistically significant variations in Group A over the peripartum period (p < 0.0001). A significant effect of pregnancy was found on all studied parameters (p < 0.001). The ACTH and cortisol levels measured in mares belonged to Group A showed a significant positive correlation with the values of leptin, LDLs, triglycerides and VLDLs, whereas they were negatively correlated with the serum UCP1 and NEFAs values. Together, the findings gathered in this study highlight a dynamic change of serum leptin, UCP1 and lipid parameters in peripartum mares and suggest an interaction of the HPA axis with lipid metabolism and mobilization in mares during the peripartum period in order to deal with metabolic and energy demand and maintain energy homeostasis.

Quantifying and Comparing the Match Demands of U18, U23, and 1ST Team English Professional Soccer Players.

The aim of this study was to quantify and compare the match load demands of U18, U23, and 1ST team players during the official season. A total of 65 matches and 495 (U18 = 146, U23 = 146, and 1ST team = 203) individual player game observations were included in this analysis. A 10-Hz global navigation satellite systems (GNSS) and 100-Hz triaxial accelerometer (STATSports, Apex, Northern Ireland) were used to monitor the following metrics during official matches: total distance, high-speed running distance (HSR), sprint distance, high metabolic distance, explosive distance, high-intensity bursts distance, speed intensity, and dynamic stress load (DSL) were analyzed. A multivariate analysis of variance test reported significant (p < 0.001) differences among the groups. HSR during matches was lower (d = small) for U18 players than the U23 and 1ST team players. Sprint distance and high-intensity bursts distance were lower (small) in U18 compared with the U23 and 1ST team. DSL was greater in 1ST compared with U18 (small) and U23 (small). This study reported that the differences between groups were greater for HSR, sprint distance, high-intensity bursts distance, and DSL, while total distance, high metabolic load distance, explosive distance, and speed intensity did not differ between the groups. These findings could be used to design training programs in the academy players (i.e., U18) to achieve the required long-term physical adaptations that are needed to progress into the U23 and 1ST teams.

High metabolic substrate load induces mitochondrial dysfunction in rat skeletal muscle microvascular endothelial cells.

The influence of glucose and palmitic acid (PA) on mitochondrial respiration and emission of hydrogen peroxide (H2O2) was determined in skeletal muscle‐derived microvascular endothelial cells. Measurements were assessed in intact and permeabilized (cells treated with 0.025% saponin) low passage endothelial cells with acute‐or prolonged (3 days) incubation with regular (1.7 mM) or elevated (2.2 mM) PA concentrations and regular (5 mM) or elevated (11 mM) glucose concentrations. In intact cells, acute incubation with 1.7 mM PA alone or with 1.7 mM PA + 5 mM glucose (p < .001) led to a lower mitochondrial respiration (p < 0.01) and markedly higher H2O2/O2 emission (p < 0.05) than with 5 mM glucose alone. Prolonged incubation of intact cells with 1.7 mM PA +5 mM glucose led to 34% (p < 0.05) lower respiration and 2.5‐fold higher H2O2/O2 emission (p < 0.01) than incubation with 5 mM glucose alone. Prolonged incubation of intact cells with elevated glucose led to 60% lower (p < 0.05) mitochondrial respiration and 4.6‐fold higher H2O2/O2 production than incubation with 5 mM glucose in intact cells (p < 0.001). All effects observed in intact cells were present also in permeabilized cells (State 2). In conclusion, our results show that acute and prolonged lipid availability, as well as prolonged hyperglycemia, induces mitochondrial dysfunction as evidenced by lower mitochondrial respiration and enhanced H2O2/O2 emission. Elevated plasma substrate availability may lead to microvascular dysfunction in skeletal muscle by impairing endothelial mitochondrial function.

Acute exercise improves glucose and TAG metabolism in young and older adults following high-fat, high-carbohydrate meal intake.

A single high-fat, high-carbohydrate meal (HFHC) results in elevated postprandial glucose (GLU), triglycerides (TAG) and metabolic load index (MLI; TAG (mg/dl) + GLU (mg/dl)) that contributes to chronic disease risk. While disease risk is higher in older adults (OA) compared to younger adults (YA), the acute effects of exercise on these outcomes in OA is understudied. Twelve YA (age 23.3 ± 3.9 yrs, n = 5 M/7 F) and 12 OA (age 67·7 ± 6.0 yrs, n = 8 M/4 F) visited the laboratory in random order to complete a HFHC with no exercise (NE) or acute exercise (EX) condition. EX was performed 12 hours prior to HFHC at an intensity of 65 % of maximal heart rate to expend 75 % of the kcals consumed in HFHC (Marie Callender's Chocolate Satin Pie; 12 kcal/kgbw; 57 % fat, 37 % CHO). Blood samples were taken at 0, 30, 60, 90 minutes, and then every hour until 6 hours post-meal. TAG levels increased to a larger magnitude in OA (Δ∼61 ± 31 %) compared to YA (Δ∼37 ± 34 %, P < 0·001), which were attenuated in EX compared to NE (P < 0·05) independent of age. There was no difference in GLU between OA and YA after the HFM, however, EX had attenuated GLU independent of age (NE: Δ∼21 ± 26 %; EX: Δ∼12 ± 18 %, P = 0·027). MLI was significantly lower after EX compared to NE in OA and YA (P < 0·001). Pre-prandial EX reduced TAG, GLU and MLI post-HFHC independent of age.