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Introduction
Skills and Expertise
Publications
Publications (257)
Nutritional epidemiology aims to link dietary exposures to chronic disease, but the instruments for evaluating dietary intake are inaccurate. One way to identify unreliable data and the sources of errors is to compare estimated intakes with the total energy expenditure (TEE). In this study, we used the International Atomic Energy Agency Doubly Labe...
Background and Aim
Professional soccer players’ self-reported dietary intakes often do not meet recommended sport nutrition guidelines. Although behaviour change models have previously explored barriers and enablers to nutritional adherence, the cultural factors influencing players’ nutritional habits also warrant investigation. Accordingly, we aim...
Background
Golf is played both recreationally and professionally by approximately 66.6 million people worldwide. Despite the potential for nutrition to influence golf performance, research in this area is somewhat limited.
Objective
To identify the existing literature regarding nutrition and golf and where the current research gaps lie.
Design
Sc...
To better understand the in-match fuelling practices of elite football players and compare against current
guidelines, we quantified the carbohydrate, fluid, and caffeine intake of players from an English Premier
League club (n = 22) during 90 min of competitive match-play. Mean carbohydrate intake across match-play
was 17 ± 11 g.h−1 with players d...
Endurance athletes fail to meet carbohydrate (CHO) guidelines for competition, which may be due to limited knowledge. However, the relationship between knowledge and practice in this population is unknown. To investigate this, we assessed the dietary intake in 50 athletes (37 females) who completed endurance events ≥2.5 h in duration and compared C...
Purpose
To test the hypothesis that training with reduced carbohydrate (CHO) availability increases bone resorption in adolescent soccer players.
Methods
In a randomised crossover design, ten male players (age: 17.4 ± 0.8 years) from an English Premier League academy completed an acute 90-min field-based training session (occurring between 10:30–1...
Female soccer players have been identified as presenting with low energy availability (LEA), though the prevalence of LEA may be overestimated given inaccuracies associated with self‐reporting dietary intakes. Accordingly, we aimed to quantify total daily energy expenditure (TDEE) via the doubly labelled water (DLW) method, energy intake (EI) and e...
Purpose
Whey protein ingestion is typically considered an optimal dietary strategy to maximize myofibrillar protein synthesis (MyoPS) following resistance exercise. While single source plant protein ingestion is typically less effective, at least partly, due to less favorable amino acid profiles, this could theoretically be overcome by blending pla...
Understanding the daily energy expenditure of athletes during training is important to support recovery, adaptation, and the maintenance of performance. The aim of the current research was to assess the total daily energy expenditure (TDEE) and the acute energy expenditure (EE) of tennis training sessions during habitual training of elite tennis pl...
Despite its growing popularity and participation rates, mixed martial arts (MMA) coaching has not been the subject of much critical scholarly analysis. Accordingly, knowledge of this activity is limited, and inadequate, as a means of understanding this MMA context, and supporting those coaches who practice in it. To begin to address this gap, we re...
Purpose: As a multi-disciplined combat sport, relationships between external and internal training loads and intensities of mixed martial arts (MMA) have not been described. The aim of this study was to determine the external loads and intensities of MMA training categories and their relationship to internal loads and intensities. Methods: 20 MMA a...
Previous studies demonstrate that “under-fuelling” (i.e., reduced carbohydrate (CHO) and energy intake (EI) in relation to recommended guidelines) is prevalent within adult female soccer players, the consequence of which may have acute performance and chronic health implications. However, the dietary practices of adolescent female soccer players, a...
There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits m...
Despite the well-documented role of carbohydrate (CHO) in promoting endurance exercise performance, endurance athletes typically fail to meet current recommendations in competition. Adequate nutrition knowledge is key to drive athletes' behaviour, but the current level of knowledge in this population is not known. The present study assessed knowled...
Purpose
Carbohydrate (CHO) intake periodization via the sleep low train low (SL‐TL) diet–exercise model increases fat oxidation during exercise and may enhance endurance‐training adaptation and performance. Conversely, training under environmental heat stress increases CHO oxidation, but the potential of combined SL‐TL and heat stress to enhance me...
The assessment of total energy expenditure (TEE) is imperative to ensure appropriate fuelling during competition and training, although the current lack of TEE research in para sport make the prescription of nutritional strategies challenging. This study aimed to assess TEE of an elite wheelchair tennis (WT) player during training and competition o...
The aim of the present study was to simultaneously audit hormonal contraceptive (HC) use, menstrual cycle characteristics and training/nutrition related profiles in pre-menopausal women from varying athletic and exercise backgrounds. Elite ( n = 51), sub-elite ( n = 118) and amateur ( n = 392) female athletes and exercisers were examined via an ano...
We identify novel epigenetically regulated genes associated with train-low sleep-low paradigms. Exercise under low-carbohydrate (CHO) energy-balance (high-fat) conditions elicited a more prominent DNA hypomethylation signature 30 minutes postexercise compared with low-CHO energy-deficit (low-fat) conditions. This was enriched within IL6-JAK-STAT si...
Purpose:
An understanding of an athlete's total daily energy expenditure (TEE) is necessary to inform nutritional strategies, particularly where daily training and competitive demands are highly variable. This observational case series assessed the TEE of elite tennis players during high-level competition.
Methods:
Senior female singles particip...
Jockeys are unique given that they make weight daily and, therefore, often resort to fasting and dehydration. Through increasing daily food frequency (during energy deficit), we have reported short-term improvements in jockey’s body composition. While these changes were observed over 6–12 weeks with food provided, it is unclear whether such improve...
Using untargeted metabolomics, we aimed to characterise the systemic impact of environmental heat stress during exercise. Twenty‐three trained male triathletes (V̇O2peak${\dot V_{{{\rm{O}}_2}{\rm{peak}}}}$ = 64.8 ± 9.2 ml kg min⁻¹) completed a 30‐min exercise test in hot (35°C) and temperate (21°C) conditions. Venous blood samples were collected im...
We aimed to investigate the human skeletal muscle (SkM) DNA methylome after exercise in low carbohydrate (CHO) energy balance (with high fat) compared with exercise in low-CHO energy deficit (with low fat) conditions. The objective to identify novel epigenetically regulated genes and pathways associated with train-low sleep-low paradigms. The sleep...
Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely reflect water turnover (WT), the water used by the body each day. We investigated the determinants of human WT in 5604 people from the ages of 8 days to 96 years from 23 countries using...
Considering that academy soccer players frequently train in the evening (i.e. 17:00-20:00 h), there is often limited time to nutritionally prepare and recover due to schooling, travel and sleep schedules. Accordingly, we assessed the timing and quantity of dietary intake of academy soccer players in the pre-training and post-training period. Over a...
Purpose: This qualitative study explores player and stakeholder perceptions of menstrual health support in elite female soccer.
Methods: Semi-structured interviews were conducted with 47 participants including players (n = 12), parents (n = 9), coaches (n = 9), sport scientists (n = 7), nutritionists (n = 5) and medical staff (n = 5).
Results: Via...
In response to the ongoing sex data gap, the present study provides a qualitative exploration of females’ nutritional experiences in elite sporting environments. Semistructured interviews were conducted with multiple participant groups ( n = 18), including athletes ( n = 7), practitioners ( n = 6), and researchers ( n = 5) across differing discipli...
In mammals, trait variation is often reported to be greater among males than females. However, to date, mainly only morphological traits have been studied. Energy expenditure represents the metabolic costs of multiple physical, physiological, and behavioral traits. Energy expenditure could exhibit particularly high greater male variation through a...
This case study follows a professional internationally capped female soccer player’s two-year journey from eumenorrhea, through injury, to amenorrhea, and the challenges faced by the player and nutritionist. The two years are split into three sections: (1) longitudinal profiling of the player, (2) nutrition to support her return from injury, and (3...
Purpose:
To test the hypothesis that a novel nutritional blend comprised of tryptophan, glycine, magnesium, tart cherry powder and L-theanine, enhances subjective and objective measures of sleep during free living conditions.
Methods:
In a randomised, repeated measures crossover and double blind deception design, participants (n = 9 male and 7 f...
Purpose:
This qualitative study explores player and stakeholder perceptions of the role of nutrition in supporting player development and performance in elite female soccer.
Methods:
Semi-structured interviews (36 ± 18 mins in length) were conducted with 47 participants, including players (n = 12), parents (n = 9), coaches (n = 9), sport scienti...
Fully revised and expanded, the second edition of Molecular Exercise Physiology offers a student-friendly introduction. It introduces a history documenting the emergence of molecular biology techniques to investigate exercise physiology, the methodology used, exercise genetics and epigenetics, and the molecular mechanisms that lead to adaptation af...
We examined the effects of carbohydrate (CHO) delivery form on exogenous CHO oxidation, gastrointestinal discomfort, and exercise capacity. In a randomised repeated measures design (after 24 h of high CHO intake (8 g·kg-1) and pre-exercise meal (2 g·kg-1)), nine trained males ingested 120 g CHO·h-1 from fluid (DRINK), semi-solid gel (GEL), solid je...
Athletes from weight-sensitive sports are reported to consume low-fiber diets (LOW) to induce acute reductions in body mass (BM). However, evidence supporting their efficacy is anecdotal. Therefore, we aimed to determine the effect of a LOW on acute changes in BM. Nineteen healthy males (32 ± 10 years, 1.79 ± 0.07 m, 77.5 ± 8.1 kg) consumed their h...
Purpose:
To audit the current provision of performance nutrition services provided to male adolescent players within academies from the English soccer leagues.
Methods:
Practitioners from all eighty-nine academies (status categorised as one-four according to the Elite Player Performance Plan, EPPP) completed an online survey to audit: a) job rol...
Objectives: To investigate if maturity status was associated with injury risk in male academy soccer players. Design: Prospective cohort surveillance study.
Setting: Professional soccer academies.
Participants: 501 players (aged 9-23 years) from eight academies in England, Spain, Uruguay and Brazil.
Main outcome measures: Players were grouped...
Despite more than four decades of research examining the physical demands of match-play, quantification of the customary training loads of adult male professional soccer players is comparatively recent. The training loads experienced by players during weekly micro-cycles are influenced by phase of season, player position, frequency of games, player...
Context
It is unclear whether playing position influences injury in male academy soccer players (ASP).
Objective
To determine if playing position is associated with injury in ASP.
Design
Descriptive Epidemiology Study.
Setting
English, Spanish, Uruguayan and Brazilian soccer academies.
Participants
369 ASP from Under 14 (U14) to U23 age groups,...
Background
It has recently been identified that manipulating carbohydrate availability around exercise activity can enhance training-induced metabolic adaptations. Despite this approach being accepted in the athletic populations, athletes do not systematically follow the guidelines. Digital environments appear to allow nutritionists to deliver this...
Low total energy expenditure (TEE, MJ/d) has been a hypothesized risk factor for weight gain, but repeatability of TEE, a critical variable in longitudinal studies of energy balance, is understudied. We examine repeated doubly labeled water (DLW) measurements of TEE in 348 adults and 47 children from the IAEA DLW Database (mean ± SD time interval:...
Muscle glycogen is an important fuel source for contracting skeletal muscle, and it is well documented that exercise performance is impaired when the muscle’s stores of glycogen are exhausted. The role of carbohydrate (CHO) availability on exercise performance has been known for more than a century, while the specific role of muscle glycogen for mu...
Aim: This study aimed to explore athletes' experiences and opinions of communication strategies in applied sports nutrition, as well as capture suggestions for future mobile app supportive solutions.
Methods: A qualitative approach was used for this research. Data was generated from semi-structured focus groups (n = 9) with a purposive sample of 4...
Purpose:
To quantify total daily energy expenditure (TEE) of international adult female soccer players.
Methods:
Twenty-four professional players were studied during a twelve-day period where they participated in an international training camp (also inclusive of two competitive games) representing the English national team. TEE was assessed via...
Background
“Sleep Low-Train Low” is a training-nutrition strategy intended to purposefully reduce muscle glycogen availability around specific exercise sessions, potentially amplifying the training stimulus via augmented cell signalling. The aim of this study was to assess the feasibility of a 3-week home-based “sleep low-train low” programme and i...
It is currently unknown if injury risk is associated with genetic variation in academy soccer players (ASP). We investigated whether nine candidate single nucleotide polymorphisms were associated (individually and in combination) with injury in ASP at different stages of maturation. Saliva samples and one season’s injury records were collected from...
Weight cycling is thought to increase the risk of obesity and cardiometabolic disease in nonathletic and athletic populations. However, the magnitude and frequency of weight cycling is not well characterized in elite athletes. To this end, we quantified the weight cycling practices of a male World Champion professional boxer competing at super midd...
Background:
Physical activity may be a way to increase and maintain fat-free mass (FFM) in later life, similar to the prevention of fractures by increasing peak bone mass.
Objectives:
A study is presented of the association between FFM and physical activity in relation to age.
Methods:
In a cross-sectional study, FFM was analyzed in relation t...
The metabolic perturbations caused by competitive rugby are not well characterized. Our aim is to utilize untargeted metabolomics to develop appropriate interventions, based on the metabolic fluctuations that occur in response to this collision-based team sport. Seven members of an English Premiership rugby squad consented to provide blood, urine,...
A lifetime of change
Measurements of total and basal energy in a large cohort of subjects at ages spanning from before birth to old age document distinct changes that occur during a human lifetime. Pontzer et al . report that energy expenditure (adjusted for weight) in neonates was like that of adults but increased substantially in the first year o...
Few data are available that describe how probiotics influence systemic metabolism during endurance exercise. Metabolomic profiling of endurance athletes will elucidate mechanisms by which probiotics may confer benefits to the athlete. In this study, twenty-four runners (20 male, 4 female) were block randomised into two groups using a double-blind m...
Understanding the impacts of activity on energy balance is crucial. Increasing levels of activity may bring diminishing returns in energy expenditure because of compensatory responses in non-activity energy expenditures.1, 2, 3 This suggestion has profound implications for both the evolution of metabolism and human health. It implies that a long-te...
Methods:
Doubly labeled water assessed TEE during a 17-d period analyzed by days 1 to 7 (P1) and 7-17 (P2) which included a Women's Tennis Association/Association of Tennis Professionals tournament and culminated at the Wimbledon Championships. Daily training and match loads were assessed using a 10-point Borg scale multiplied by time. Match data...
Optimal carbohydrate and protein intakes are vital for modulating training adaptation, recovery, and exercise performance. However, the research base underpinning contemporary sport nutrition guidelines has largely been conducted in male populations with a lack of consensus on whether the menstrual phase and associated changes in sex hormones allow...
Purpose
To audit hormonal contraceptive use and associated symptomology in elite women’s soccer in England.
Methods
Seventy-five elite women’s soccer players from the Women’s Super League (WSL) completed a questionnaire to assess: hormonal contraceptive (HC) use or non-use, reasons for initiation and discontinuation and the symptoms experienced by...
The aim of this study was to quantify typical training load and periodisation practices of MMA athletes. MMA competitors (n = 14; age = 22.4 ± 4.4 years; body mass = 71.3 ± 7.7 kg; stature = 171 ±9.9 cm) were observed during training for 8 consecutive weeks without intervention. Seven athletes were training for competitive bouts whilst the remainin...
Key points
Muscle glycogen and intramuscular triglycerides (IMTG, stored in lipid droplets) are important energy substrates during prolonged exercise.
Exercise‐induced changes in lipid droplet (LD) morphology (i.e. LD size and number) have not yet been studied under nutritional conditions typically adopted by elite endurance athletes, that is, afte...
There has been substantial progress in the knowledge of exercise and type 1 diabetes, with the development of guidelines for optimal glucose management. In addition, an increasing number of people living with type 1 diabetes are pushing their physical limits to compete at the highest level of sport. However, the post-exercise recovery routine, part...
Sports nutrition is becoming increasingly recognised as one of the most important sub-disciplines of strength and conditioning. In the UK, sports nutritionists (commonly referred to as performance nutrition- ists or sports dieticians if the practitioner is clinically trained) usually work on a consultancy basis, though there are now an increasing n...
Whilst the assessment of body composition is routine practice in sport, there remains considerable debate on the best tools available, with the chosen technique often based upon convenience rather than understanding the method and its limitations. The aim of this manuscript was threefold: 1) provide an overview of the common methodologies used with...
We quantified on pitch external loading of English Premier League (EPL) academy soccer players (n=76; U12-U18 age groups) over an entire competitive season. Mean accumulative weekly duration and total distance, respectively, was similar in the U12 (329±29 min; 19.9±2.2 km), U13 (323±29 min; 20.0±2.0 km) and U14 (339±25 min; 21.7±2.0 km; P>0.05 for...
The doubly labeled water (DLW) method measures total energy expenditure (TEE) in free-living subjects. Several equations are used to convert isotopic data into TEE. Using the International Atomic Energy Agency (IAEA) DLW database (5,756 measurements of adults and children), we show considerable variability is introduced by different equations. The...
The remote food photography method (RFPM), often referred to as ‘Snap-N-Send’ by sport nutritionists, has been reported as a valid method to assess energy intake in athletic populations. However, preliminary studies were not conducted in true free-living conditions and dietary assessment was performed by one researcher only. We therefore assessed t...
This investigation sought to determine whether post-exercise cold water immersion and low glycogen availability, separately and in combination, would preferentially activate either the Exon 1a or Exon 1b Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) promoter. Through a reanalysis of sample design, we identified that...
Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising...
Purpose: To evaluate the effects of low energy availability (EA) on health and performance indices associated with the Male Athlete Triad and Relative Energy Deficiency in Sports (RED-S) models.
Methods: Over an 8 week period, a male combat sport athlete adhered to a phased body mass (BM) loss plan consisting of 7 weeks energy intake (EI) equating...
New findings:
What is the central question of this study? Does achieving energy balance mainly with ingested fat in a 'sleep-low' model of training with low muscle glycogen affect the early training adaptive response during recovery? What is the main finding and its importance? Replenishing the energy expended during exercise mainly from ingested...
