Development of an expert system for the classification of myalgic encephalomyelitis/chronic fatigue syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe condition with an uncertain origin and a dismal prognosis. There is presently no precise diagnostic test for ME/CFS, and the diagnosis is determined primarily by the presence of certain symptoms. The current study presents an explainable artificial intelligence (XAI) integrated machine learning (ML) framework that identifies and classifies potential metabolic biomarkers of ME/CFS. Metabolomic data from blood samples from 19 controls and 32 ME/CFS patients, all female, who were between age and body mass index (BMI) frequency-matched groups, were used to develop the XAI-based model. The dataset contained 832 metabolites, and after feature selection, the model was developed using only 50 metabolites, meaning less medical knowledge is required, thus reducing diagnostic costs and improving prognostic time. The computational method was developed using six different ML algorithms before and after feature selection. The final classification model was explained using the XAI approach, SHAP. The best-performing classification model (XGBoost) achieved an area under the receiver operating characteristic curve (AUCROC) value of 98.85%. SHAP results showed that decreased levels of alpha-CEHC sulfate, hypoxanthine, and phenylacetylglutamine, as well as increased levels of N-delta-acetylornithine and oleoyl-linoloyl-glycerol (18:1/18:2)[2], increased the risk of ME/CFS. Besides the robustness of the methodology used, the results showed that the combination of ML and XAI could explain the biomarker prediction of ME/CFS and provided a first step toward establishing prognostic models for ME/CFS.

Comprehensive review of melatonin as a promising nutritional and nutraceutical supplement

Background

Melatonin is an indoleamine hormone secreted by the pineal gland at night and has an essential role in regulating human circadian rhythms (the internal 24-h clock) and sleep-wake patterns. However, it has recently gained considerable attention for its demonstrated ability in disease management. This review discusses the major biological activities of melatonin, its metabolites as nutritional supplements, and its bioavailability in food sources.

Methods

The information acquisition process involved conducting a comprehensive search across academic databases including PubMed, Scopus, Wiley, Embase, and Springer using relevant keywords. Only the most recent, peer-reviewed articles published in the English language were considered for inclusion.

Results

The molecular mechanisms by which melatonin induces its therapeutic effects have been the subject of various studies.

Conclusion

While melatonin was initially understood to only regulate circadian rhythms, recent studies indicate that it has a far-reaching effect on various organs and physiological systems, such as immunity, cardiovascular function, antioxidant defense, and lipid hemostasis. As a potent antioxidant, anti-cancer, anti-inflammatory, and immunoregulatory agent, multiple therapeutic applications have been proposed for melatonin.

Sarcopenia of Ageing: Does a Healthier Lifestyle Matter in Reversing the Trajectory? A Brief Narrative Review and a Call for Action in Saudi Arabia

The concept of health span is an emerging topic in recent years, with a truly palpable relevance to public health. With ageing comes a loss of skeletal muscle mass, strength, and performance, which is termed as sarcopenia. Sarcopenia is a major public health concern and poses a challenge to health-care systems. Modifiable lifestyle factors may be linked to the course of sarcopenia progression. Many countries developed diagnostic tools to accurately detect sarcopenia for its prevention, delay, or treatment. However, to date, there is no sufficient information regarding the status of sarcopenia in Saudi Arabia. The review aims to discuss sarcopenia and relevant updates in research and literature, the association with modifiable lifestyle factors, the implications of sarcopenia in a rapidly developing country such as Saudi Arabia, and the current state and need for research in Saudi Arabia in this domain along with future directions in combating this disease.

Public policies to increase physical activity and reduce sedentary behavior: a narrative synthesis of "reviews of reviews"

BACKGROUND

Physical inactivity among the general population is of great concern in public health.

OBJECTIVE

This narrative review aims to identify promising physical activity (PA) public policies based on the best available evidence from the literature.

METHODS

The study is a narrative synthesis of 'reviews of reviews' of public policies designed to increase physical activity among either (a) youths or (b) the community at large. We searched the literature for reviews of reviews of public policies of any country relevant to physical activity, physical inactivity, or sedentary behaviour published since 1 January 2000, in four databases.

RESULTS

Based on 12 reviews of reviews published between 2011 and 2022, we identified seven potentially effective PA public policies. Six of the seven were youth-based public policies that would be implemented in schools. The seventh was a policy aimed at establishing and promoting walking groups.

CONCLUSIONS

Policymakers seeking to increase PA should consider focusing on school-based PA policies and community-based walking groups, as this is where the evidence base is greatest. To implement these policies, pilot studies to assess the efficacy of such programmes in local communities should first be conducted due to methodological limitations in the underlying literature and questions of generalisability and reproducibility.

Does body mass index distinguish motor proficiency, social and emotional maturity among adolescent girls?

BACKGROUND

The objective of this study was to investigate whether different body mass index (BMI) groups could serve as a distinguishing factor for assessing motor proficiency and social and emotional maturity in adolescent girls.

METHODS

140 girls ranging from 12 to 14.5 years old were selected from the schools of Tabriz city, Iran. After their height and weight were measured to calculate body mass index, they completed the following questionnaires: Bruininks-Oseretsky Test of motor proficiency, Second Edition,Vineland Social Maturity Scale, and Emotional Maturity scale.

RESULTS

normal-weight girls had a meaningful advantage against overweight and underweight participants in the gross motor factor of motor proficiency (p = 0.004), but there wasn't a meaningful difference in the fine motor p = 0.196) and coordination factors (p = 0.417). Also, social maturity showed an advantage of normal and underweight adolescent girls in the self-help dressing factor (p = 0.018), while the locomotion skills (p = 0.010) factor revealed a better performance of normal weight and overweight groups over underweight adolescents. No significant differences were observed in the emotional maturity subscales (p = 0.63) between the groups.

CONCLUSIONS

The present study demonstrates that BMI has a direct influence on adolescents' gross motor proficiency and social maturity.

Effects of combined aerobic exercise and diet on cardiometabolic health in patients with obesity and type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Lifestyle modifications involving diet and exercise are recommended for patients diagnosed with obesity and type 2 diabetes mellitus (T2DM). The purpose of this review was to systematically evaluate the effects of combined aerobic exercise and diet (AEDT) on various cardiometabolic health-related indicators among individuals with obesity and T2DM.

METHODOLOGY

A comprehensive search of the PubMed/Medline, Web of Science, Scopus, Science Direct, Cochrane, and Google Scholar databases was conducted for this meta-analysis. The Cochrane risk of bias tool was used to evaluate eligible studies, and the GRADE tool was used to rate the certainty of evidence. A random-effects model for continuous variables was used, and the results were presented as mean differences or standardised mean differences with 95% confidence intervals.

RESULTS

A total of 16,129 studies were retrieved; 20 studies were included, and data were extracted from 1,192 participants. The findings revealed significant improvements in body mass index, body weight, waist circumference, systolic blood pressure, diastolic blood pressure, total cholesterol, triglycerides, fasting blood glucose, fasting plasma insulin, glycated hemoglobin, leptin, interleukin-6, C-reactive protein, and adiponectin (p < 0.05) compared to the standard treatment (ST) group. No significant differences were observed between the AEDT and ST groups in fat mass, hip circumference, waist-to-hip ratio, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and tumor necrosis factor-alpha. The present findings are based on low- to moderate-quality evidence.

CONCLUSIONS

AEDT may be a critical behavior for holistic cardiometabolic health-related benefits as a contemporary anti-obesity medication due to its significant positive impact on patients with obesity and T2DM. Nevertheless, further robust evidence is necessary to determine whether AEDT is an effective intervention for lowering cardiovascular and metabolic risk factors among individuals with obesity and T2DM.

Impacts of different triathlon races on systemic cytokine profile and metabolic parameters in healthy individuals: a systematic review

The present systematic review aimed to discuss the impacts of different triathlon protocols on the level of pro and anti-inflammatory cytokines, as well as biomarkers related to the performance of healthy individuals. Four databases [PubMed (28 articles), Scopus (24 articles), Science Direct (200 articles), and SPORT Discus (1101 articles) were assessed. The eligibility criteria were applied, and the selected articles were used in the peer review, independently, as they were identified by March 2022. Of the 1359 articles found, 10 were included in this systematic review. Despite the difference in triathlon protocols, it was observed an increase in pro and anti-inflammatory cytokines including IL-4 and IL-10, and chemokines, such as IL-8 and MCP-1. Moreover, the anti-inflammatory serum levels increase after triathlon. Overall, the studies also reported enhancement in the serum levels of cortisol, creatine kinase, C reactive protein, Endothelial Growth Factor, Vascular Endothelial Growth Factor, Myostatin, Lactate dehydrogenase, free fatty acids, and lactate dehydrogenase in triathlon athletes. This systematic review indicates that different triathlon race promotes an acute elevation of circulating cytokines and chemokines levels which return to standard levels after triathlon races. The findings of this systematic review demonstrate that the modulation of inflammatory parameters may be associated with an increase in metabolic indicators (CK, Cortisol, and LDH) after the end of different types of triathlon races.

Virtual Behavioral Intervention to Promote Healthy Lifestyle Behaviors: A Feasibility RCT during COVID-19 Pandemic

BACKGROUND

the COVID-19 pandemic has had a substantial impact on human health, affecting many lifestyle behaviors such as physical activity, sedentary behavior, dietary habits and sleep.

PURPOSE

to assess the feasibility of six sessions of a virtual behavioral intervention to promote healthy lifestyle practices during a stay-at-home advisory phase of the COVID-19 pandemic.

METHODS

A participant-blinded randomized controlled trial was performed through a virtual platform setting. Participants were randomly assigned into two groups. They were assigned to a motivational interviewing (MI) intervention or attention group, with pre- and postintervention assessments. The MI treatment consisted of six sessions (twice each week). The same number of virtual structured sessions were provided for the attention group, and they provided brief advice to promote healthy lifestyles. The study was conducted from April to June 2020.

RESULTS

The feasibility outcomes indicated that 39 of the 50 participants (78%) completed the trial. The dropout rate was 21.7% for the attention group and 22.2% for the intervention group. Participating in MI had a significant positive interventional effect on physical activity level, distress and fear of COVID-19.

CONCLUSIONS

It is feasible to deliver behavioral change interventions virtually. Further, MI can be used as a useful strategy for the favorable promotion of a healthy lifestyle.

TRIAL REGISTRATION

NCT05392218 (26/05/2022).

Development of the Arabic Health Measures database: a bibliometric analysis of Arabic health-related measures

Background

To develop an open-access database of Arabic health measures intended for use by researchers and healthcare providers, along with a bibliometric analysis of the measures included in the database.

Methods

A search was conducted up to 31 December 2021 in PubMed, Embase, CINAHL, SAGE, Springer and Elsevier for published articles or abstracts with keywords “Arabic” AND “translation”, “adaptation” OR “validation”. Information on the measure and the methodology used in the study was then entered into a database. An open-access platform was developed to allow users to search for measures according to their needs. A bibliometric analysis of the articles and measures was then conducted.

Results

A total of 894 publications met the inclusion criteria. The articles discussed 716 measures that were developed using participants from at least 38 countries. The number of measures for adults was five times that for children. Mental health was the most frequent construct assessed (11.5%), followed by “function/disability” measures (10.6%). The majority of measures (54%) required 5 minutes or less to complete. Approximately 17% of the tools were available directly from the article. Saudi Arabia and Lebanon had the greatest number of publications, with 217 (23%) and 114 (12%), respectively. The majority of the publications included reporting of the validation and reliability of the instruments (64% and 56%, respectively).

Conclusions

There is a paucity of research on the quantity and quality of Arabic health measures. Similar to previous reviews, we found the number of publications on Arabic measures to be limited in comparison to those in English; however, it is encouraging that the number of publications appears to have increased steadily over the past decade. While we found the majority of publications reported on psychometric testing, we are unable to comment on the quality of the methodology used, and further investigation into this area is recommended. As the Arabic Health Measures database will facilitate the search for health instruments that have published data on their development, this will increase their visibility and use in research and clinical settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12961-022-00890-7.

Prevalence of sarcopenia among Saudis and its association with lifestyle behaviors: Protocol for cross-sectional study

Background

Sarcopenia is an age-related muscular disease manifesting as a loss of muscle function and mass–leads to detrimental consequences at both individual and community levels. Modifiable lifestyle factors (such as physical behaviors and nutritional habits) may be involved in sarcopenia etiology. European Working Group on Sarcopenia in Older Population (EWGOSP2) established a cut-off point for sarcopenia diagnosis based on the European population and they recommend the use of a regional normative population. However, no sufficient data on sarcopenia prevalence is presently available in Saudi Arabia. Therefore, this project aims to define appropriate reference values from healthy Saudi young adults (Phase I) and to investigate the prevalence of sarcopenia in Saudi Arabia (Phase II) and examine selected modifiable lifestyle correlates of sarcopenia (Phase I, II).

Methods

The project will involve two phases. Phase I will include 1532 healthy Saudi young adults aged between 20–40 years. While, Phase II will include 1532 Saudi older adults aged ≥50 years. The study will measure vital signs, anthropometrics, muscle mass using bioelectrical impedance analysis and dual-energy X-ray absorptiometry, muscle strength using handgrip strength and maximal isometric strength, physical function using short physical performance battery, and 6-minute walk test to measure aerobic endurance. To explore the associations between lifestyle behaviors with sarcopenia indices, physical activity, sedentary behaviour and sleep will be evaluated subjectively using Global Physical Activity Questionnaire and Pittsburgh Sleep Quality Index and objectively via ActivPAL accelerometers. A three-day dietary food record will also be used to evaluate dietary intake. Additionally, EuroQOL five-dimension questionnaire will be utilized to assess health-related quality of life.

Discussion

The study will have significant implications in recognizing the prevalence of sarcopenia in Saudi population, which will guide our future interventional studies aimed at early prevention and treatment of this disease.

The Impact of COVID-19 Pandemic on Weight and Body Mass Index in Saudi Arabia: A Longitudinal Study

The COVID-19 pandemic has had a major impact on various health conditions. The objective of this study was to assess the impact of the COVID-19 pandemic on body weight and body mass index (BMI) in Saudi Arabia. We used electronic health records obtained from a healthcare system representing five hospitals in three different regions in the Kingdom to examine the change in weight utilizing a longitudinal design. The study included all adults who had visited outpatient clinics in two different time points, pre-2020 (years 2018 and 2019 prior to COVID-19) and post-2020 (the year 2021). Weight and BMI changes in percentages were described. Also, bivariate chi-square test, paired t-test, and multivariable multinomial logistic regression model were used for the analyses. A total of 165,279 individuals were included in the study. On average, a significant weight gain of 0.33 kg (95% CI: 0.29-0.36) was observed in our study. Approximately 10% of the population had shifted to either overweight or obese BMI classes during the study period, as 4.8% of those with normal BMI pre-2020 had shifted to overweight or obese classes at post-2020, and 5.1% of those who were overweight had shifted to obese class. Also, 23.1% of the population had gained 5% or more of their pre-2020 weight, while 17% had lost 5% or more. Young individuals were over three times more likely to gain 5% or more than older individuals (OR: 3.34; 95% CI: 3.12-3.56). Females had 24% higher odds to gain 5% or more of their pre-2020 weight than males (OR: 1.24; 95% CI: 1.21-1.27). Diabetics were 27% more likely to lose 5% or more than non-diabetics (OR: 1.27; 95% CI: 1.23-1.31). Our findings provide insights into the impact of COVID-19 on weight and population health. Further investment in interventions for weight management is warranted during similar circumstances such as lockdowns due to infection waves or new variants. Future studies are also needed to explore the modifications that have occurred during the pandemic in the weight-related lifestyle factors such as dietary choices and physical activity levels.

Anthropometric Measurements, Sociodemographics, and Lifestyle Behaviors among Saudi Adolescents Living in Riyadh Relative to Sex and Activity Energy Expenditure: Findings from the Arab Teens Lifestyle Study 2 (ATLS-2)

The aim of the study was to examine the anthropometric measurements, sociodemographics, and lifestyle behaviors among Saudi adolescents relative to sex and physical activity (PA). A random cross-sectional survey conducted on Saudi adolescents from secondary schools in Riyadh, using a multistage stratified cluster sampling technique. Measurements included demographics, weight, height, waist circumference, PA, sedentary behaviors (SB), sleep duration, and dietary habits using a validated questionnaire. A total of 1262 adolescents (16.4 ± 0.95 years; 52.4% males) were studied. Overweight/obesity was more than 40%. Physical inactivity among adolescents was 53%, which indicates some improvement over the past years, especially among females. More than 80% of adolescents had over three hours/day of screen time, with no significant sex differences. Insufficient sleep was highly prevalent with gender differences. A large proportion of the participants did not consume daily breakfast (65.7%), vegetables (73.2%), fruits (84.2%), or milk/dairy products (62.4%), whereas significant proportions of the adolescents consumed sugar-sweetened drinks, fast food, French fries/potato chips, cake/donuts, and chocolates/candy on at least three days or more per week. It was concluded that non-daily intake of breakfast and vegetables was significantly associated with lower PA. The updated information can aid in effectively planning and implementing promotional programs toward improving the lifestyle behaviors of Saudi adolescent.

Lifestyle behaviors trend and their relationship with fear level of COVID-19: Cross-sectional study in Saudi Arabia

INTRODUCTION

COVID-19 pandemic cautionary measures have affected the daily life of people around the globe. Further, understanding the complete lifestyle behaviors profile can help healthcare providers in designing effective interventions and assessing overall health impact on risk of disease development. Thus, this study aims to assess the complete spectrum of lifestyle behaviors (physical activity, sedentary behavior, sleep, distress, social support, dietary habits, and smoking) prevalence and its association with fear of COVID-19 in people living in Saudi Arabia.

METHODS

Self-administered survey consisted of seven sections was used to collect data on fear of COVID-19 using Fear of COVID-19 Scale (FCV-19S), physical activity and sedentary behavior using the Global Physical Activity Questionnaire (GPAQ), sleep quality using the Pittsburgh Sleep Quality Index (PSQI), psychosocial distress using Kessler Psychological Distress Scale (K-10), social support using the MOS social support survey, and dietary habits using a short version of food frequency questionnaire (FFQ). The online survey was distributed via social media platforms during lockdown period of COVID-19 pandemic (May-June 2020). Each section consisted of validated questionnaire examining one of aforementioned lifestyle behaviors. Associations were analyzed using multiple linear regression.

RESULTS

A total of 669 individuals attempted to complete the online survey, 554 participants completed at least 2 sections of the survey (82.8%), and 41.3% (n = 276) completed the whole online survey. The majority of the sample were female (83%), not smokers (86.5%), had sufficient sleep duration (7.5 hrs ± 2.1), and only indicated mild level of distress (21.4 ± 8.9); they also reported high level of sedentary behavior (7.7 hrs ± 4.5), poor sleep quality (5.4 ± 2.4), were not engaged in healthy eating habits, and moderate level of perceived social support (62.0% ± 27). Only physical activity results indicated that about half of the sample were engaged in moderate to vigorous level of physical activity (54.3%). Further, being female (β = 0.12; 95% CI: 0.45, 2.94) and married (β = 0.13; 95% CI: 0.3, 2.63) were associated with fear of COVID-19 level (β = 0.21; 95% IC: 0.05, 0.19) with a confidence interval level of 95%. In addition, distress was associated with fear.

CONCLUSION

The trend of lifestyle behaviors measured during lockdown period changed from previously published rates. Future research needs to establish the short-term and long-term effect of lifestyle behaviors complete profile on physical and mental health.

The recommended amount of physical activity, sedentary behavior, and sleep duration for healthy Saudis: A joint consensus statement of the Saudi Public Health Authority

BACKGROUND:

The goal of the 24-h Movement Practice Guidelines for Saudi Arabia is to provide policymakers, health-care providers, researchers, sports professionals, and members of the public with recommendations on the duration of time they should spend engaged in physical activity, sedentary behavior, and sleep throughout all age groups.

METHODS:

A modified RAND appropriateness method and the “GRADE-ADOLOPMENT” approach of guideline recommendations were used by a guideline development panel to develop the present recommendations.

RESULTS:

The recommendations were based on the integrated needs of the following age groups: children (0–2 years), preschoolers (3–5 years), children and adolescents (6–17 years), adults (18–64 years), and older adults (≥65 years). The guidelines also include special considerations for sleep duration in the Saudi culture, such as dawn prayer and Ramadan.

CONCLUSIONS:

Several research gaps in physical activity, sedentary behavior, and sleep were identified and highlighted by the guideline development panel for potential future research.

Joint consensus statement of the Saudi Public Health Authority on the recommended amount of physical activity, sedentary behavior, and sleep duration for healthy Saudis: Background, methodology, and discussion

The Saudi Public Health Authority recently prepared a Consensus Statement regarding how much time a person should spend engaged in physical activity, sedentary behavior, and sleep to promote optimal health across all age groups. This paper describes the background literature, methodology, and modified RAND Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation (GRADE)-ADOLOPMENT approach that guided the development process. A Leadership Group and Consensus Panels were formed, and credible existing guidelines were identified. The Panel identified clear criteria to choose the best practice guidelines for the set objectives after evaluation, based on GRADE table evidence, findings table summaries, and draft recommendations. Updating of the selected practice guidelines was performed, and the Consensus Panels separately reviewed the evidence for each behavior and decided to adopt or adapt the selected practice guideline recommendations or create de novo recommendations. Data related to cultural factors that may affect the studied behaviors, such as prayer times, midday napping or "Qailulah," and the holy month of Ramadan, were also reviewed. Two rounds of voting were conducted to reach a consensus for each behavior.

Reliability of Time to Exhaustion Treadmill Running as a Measure of Human Endurance Capacity

Little if any research has examined the variability in time to exhaustion (TTE) during submaximal treadmill running. This study investigated the test-retest reliability of submaximal treadmill TTE as a measure of endurance capacity. 16 endurance-trained males (n=14) and females (n=2) completed a run to exhaustion at 70% V̇O2max (T1) and repeated the same run 3 weeks later (T2). At 30-min intervals during each run, expired gas, heart rate (HR) and ratings of perceived exertion (RPE) were collected. Mean ± SD TTE was 96 ± 20 min in T1 vs. 101 ± 29 min in T2 (P=0.3). The mean ± 95% confidence intervals (CI) of the coefficient of variance (CV) was 5.4% (1.4-9.6). The average intraclass correlation coefficient (± 95% CI) was 0.88 (0.67-0.96) between trials. The respiratory-exchange ratio was not different between trials, T1: 0.87 ± 0.1 and T2: 0.89 ± 0.1 (P>0.05) and neither was total whole-body carbohydrate oxidation (2.1 ± 0.4 g·min(-1) and 2.3 ± 0.6 g·min(-1)), fat oxidation (0.6 ± 0.2 g·min(-1)), HR (178 ± 8 and 175 ± 7 beats·min(-1)) or RPE (17 ± 3 and 16 ± 3). These results suggest that use of prolonged treadmill-based TTE can be a reliable research tool to assess human endurance capacity in aerobically-trained men and women.

Post-Exercise Protein Trial: Interactions between Diet and Exercise (PEPTIDE): study protocol for randomized controlled trial

BACKGROUND

Performing regular exercise is known to manifest a number of health benefits that mainly relate to cardiovascular and muscular adaptations to allow for greater oxygen extraction and utilization. There is increasing evidence that nutrient intake can affect the adaptive response to a single exercise bout, and that protein feeding is important to facilitate this process. Thus, the exercise-nutrient interaction may potentially lead to a greater response to training. The role of post-exercise protein ingestion in enhancing the effects of running-based endurance exercise training relative to energy-matched carbohydrate intervention remains to be established. Additionally, the influence of immediate versus overnight protein ingestion in mediating these training effects is currently unknown. The current protocol aims to establish whether post-exercise nutrient intake and timing would influence the magnitude of improvements during a prescribed endurance training program.

METHODS/DESIGN

The project involves two phases with each involving two treatment arms applied in a randomized investigator-participant double-blind parallel group design. For each treatment, participants will be required to undergo six weeks of running-based endurance training. Immediately post-exercise, participants will be prescribed solutions providing 0.4 grams per kilogram of body mass (g · kg(-1)) of whey protein hydrolysate plus 0.4 g · kg(-1) sucrose, relative to an isocaloric sucrose control (0.8 g · kg(-1); Phase I). In Phase II, identical protein supplements will be provided (0.4 + 0.4 g · kg(-1) · h(-1) of whey protein hydrolysate and sucrose, respectively), with the timing of ingestion manipulated to compare immediate versus overnight recovery feedings. Anthropometric, expired gas, venous blood and muscle biopsy samples will be obtained at baseline and following the six-week training period.

DISCUSSION

By investigating the role of nutrition in enhancing the effects of endurance exercise training, we will provide novel insight regarding nutrient-exercise interactions and the potential to help and develop effective methods to maximize health or performance outcomes in response to regular exercise.

TRIAL REGISTRATION

Current Controlled Trials registration number: ISRCTN27312291 (date assigned: 4 December 2013). The first participant was randomized on 11 December 2013.

Exploring mechanisms of fatigue during repeated exercise and the dose dependent effects of carbohydrate and protein ingestion: study protocol for a randomised controlled trial

Background

Muscle glycogen has been well established as the primary metabolic energy substrate during physical exercise of moderate- to high-intensity and has accordingly been implicated as a limiting factor when such activity is sustained for a prolonged duration. However, the role of this substrate during repeated exercise after limited recovery is less clear, with ongoing debate regarding how recovery processes can best be supported via nutritional intervention. The aim of this project is to examine the causes of fatigue during repeated exercise bouts via manipulation of glycogen availability through nutritional intervention, thus simultaneously informing aspects of the optimal feeding strategy for recovery from prolonged exercise.

Methods/Design

The project involves two phases with each involving two treatment arms administered in a repeated measures design. For each treatment, participants will be required to exercise to the point of volitional exhaustion on a motorised treadmill at 70% of previously determined maximal oxygen uptake, before a four hour recovery period in which participants will be prescribed solutions providing 1.2 grams of sucrose per kilogram of body mass per hour of recovery (g.kg^-1.h^-1) relative to either a lower rate of sucrose ingestion (that is, 0.3 g.kg^-1. h^-1; Phase I) or a moderate dose (that is, 0.8 g.kg^-1.h^-1) rendered isocaloric via the addition of 0.4 g.kg^-1.h^-1 whey protein hydrolysate (Phase II); the latter administered in a double blind manner as part of a randomised and counterbalanced design. Muscle biopsies will be sampled at the beginning and end of recovery for determination of muscle glycogen resynthesis rates, with further biopsies taken following a second bout of exhaustive exercise to determine differences in substrate availability relative to the initial sample taken following the first exercise bout.

Discussion

Phase I will inform whether a dose–response relationship exists between carbohydrate ingestion rate and muscle glycogen availability and/or the subsequent capacity for physical exercise. Phase II will determine whether such effects are dependent on glycogen availability per se or energy intake, potentially via protein mediated mechanisms.

Trial registration

ISRCTN87937960.

Metabolic limitations of performance and fatigue in football

Football participation requires considerable utilization of both aerobic and anaerobic energy systems to match the high energetic demands of the sport. The consequent stresses imposed on the physiological and metabolic systems carries players to the threshold of exhaustion during match-play, from which they are required to recover in preparation for the subsequent game. A high number of players experience fatigue during the high-intensity bouts and a consequent decline in their performance towards the end of the game is a likely outcome during match-play. The current review aims to establish the current understanding that relates to metabolic limitations of performance and the associated mechanisms for the onset of fatigue that may be instrumental in further development of evidence-based nutritional and training interventions in this event.

Carbohydrate-protein ingestion improves subsequent running capacity towards the end of a football-specific intermittent exercise

The majority of football players succumb to fatigue towards the end of the game. This study was designed to examine the influence of protein coingestion with carbohydrate (CHO) vs. an isocaloric CHO supplement on subsequent running capacity towards the end of a simulated football match. Six male amateur football players participated in 3 trials applied in a randomized cross-over experimental design. A laboratory-based, football-specific intermittent exercise was allocated for 75 min interspersed with a 15-min recovery, immediately followed by run time to fatigue (RTF) at 80% peak oxygen consumption. In each trial, prior to exercise and during half-time, participants randomly ingested a placebo (PLC), 6.9% CHO, or 4.8% CHO plus 2.1% protein (CHO-P) supplements matched for color and taste. CHO-P resulted in longer RTF (23.02 ± 5.27 min) than did CHO (16.49 ± 3.25 min) and PLC (11.00 ± 2.80 min) (p < 0.05). Blood glucose was higher in CHO-P at the point of fatigue (4.68 ± 0.64) compared with CHO and PLC (3.92 ± 0.29 and 3.66 ± 0.36, respectively; p < 0.05). Ratings of perceived exertion were lower in the CHO-P subjects at the onset of exercise and towards the end of intermittent exercise when compared with the PLC and CHO subjects (p < 0.05). When protein was added to a CHO supplement, subsequent running capacity following limited recovery from intermittent exercise was enhanced. This improvement suggests that protein coingestion may exert an ergogenic benefit upon endurance capacity during intermittent activity.