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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 signaling, metabolic processes, p53, cell cycle, oxidative phosphorylation, and fatty acid metabolism. Histone deacetylase (HDAC) family members 2, 4, 10, and 11 demonstrated hypomethylation, with HDAC2 and HDAC11 possessing alternative regulation of gene expression in energy balance versus deficit conditions.

This qualitative study explores player and stakeholder perceptions of menstrual health support in elite female soccer.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).Via thematic analysis, data demonstrate that elite female soccer players experience a range of physical and psychological symptoms primarily at the onset of and during menses (as also perceived by stakeholders), with most participants perceiving these symptoms to impact performance. Nonetheless, menstrual health support is perceived as minimal and although players have their menstrual status tracked, they report little understanding as to why or how this information is used. This confusion was also present among stakeholders, often as a result of uncertainty about the evidence supporting the need for menstrual health support. The perceived lack of support may also be reflective of a culture where conversations about the menstrual cycle are not normalised. Overall, this may result in failure to identify and treat menstrual irregularities despite non-coaching staff members perceiving them to be common amongst players.These data support the need for individualised support based on the lived experiences of individual players and support staff. Furthermore, our research identifies the need for organisational, stakeholder, and player centred education programmes (led by experts in female athlete health) that create an environment where players receive personalised menstrual health support.

Purpose Despite unequivocal evidence demonstrating high carbohydrate (CHO) availability improves endurance performance, athletes often report under-eating CHO during competition. Such findings may be related to a lack of knowledge though currently there are no practical or time-efficient tools to assess CHO knowledge in athletes. Accordingly, we aimed to validate a novel questionnaire to rapidly assess endurance athletes’ knowledge of competition CHO guidelines. Methods The Carbohydrate for Endurance Athletes in Competition Questionnaire (CEAC-Q) was created by research-active practitioners, based on contemporary guidelines. The CEAC-Q comprised 25 questions divided into 5 subsections (assessing CHO metabolism, CHO loading, pre-event meal, during-competition CHO and recovery) each worth 20 points for a total possible score of 100. Results A between-group analysis of variance compared scores in three different population groups to assess construct validity: general population (GenP; n = 68), endurance athletes (EA; n = 145), and sports dietitians/nutritionists (SDN; n = 60). Total scores were different (mean ± SD) in all pairwise comparisons of GenP (17 ± 20%), EA (46 ± 19%) and SDN (76 ± 10%, p p r = 0.742, p Conclusion Taking ~ 10 min to complete, the CEAC-Q is a new psychometrically valid, practical and time-efficient tool for practitioners to assess athletes’ knowledge of CHO for competition and guide subsequent nutrition intervention.

Men are often considered as the default sex for studies in sports nutrition. Indeed, most of the seminal work to date in sports nutrition has been exclusively conducted on male participants. The 2021 Olympic Games had 49% female participation, signalling [almost] parity between sportsmen and sportswomen at the most elite sporting level for the first time. The volume of sports nutrition research using women as participants has, however, not kept pace with this rise in participation and professionalism. Therefore, to highlight what we currently know and don't know about sports nutrition for female athletes we invited well-known and emerging researchers to contribute to this special edition on Nutrition for Female Athletes. Contributions cover three main themes: dietary and hydration requirements; low energy availability and making weight; and dietary supplements and gut health. In addition, this special addition explores why our understanding on this topic is limited and how we can further progress and promote this research area.

This qualitative study explores player and stakeholder perceptions of the role of nutrition in supporting player development and performance in elite female soccer. Semi-structured interviews (36 ± 18 mins in length) 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). Via thematic analysis, data provided an insight into the nutrition culture within elite women's soccer. Data demonstrate that considerable confusion and misconceptions exist amongst players and stakeholders regarding the theoretical underpinning and practical application of meeting energy requirements, colloquially referred to as "fuelling". As such, it is perceived that players "under-fuel", which is likely caused by misunderstandings about the impact of carbohydrate intake on body composition, a fear of weight gain and the associated impacts upon body image. The "carbohydrate fear" that is experienced by players is exacerbated by external pressures arising from social media, key stakeholders (e.g., coaches) and the skinfold culture surrounding measurement of body composition. Such cultural issues are amplified by the lack of full-time professionally accredited nutritionists overseeing the provision of nutrition support. Indeed, the infrastructure supporting the women's game (e.g. staffing resource, on-site food provision, player education programmes etc.) was considered incomparable to the men's game. When taken together, our data provide a platform for which to develop organisational, stakeholder and player centred education and behaviour change interventions that strive to promote a positive performance nutrition culture within the women's game.

Energy availability (EA) is defined as the amount of dietary energy available to sustain physiological function after subtracting the energetic cost of exercise. Insufficient EA due to increased exercise, reduced energy intake, or a combination of both, is a potent disruptor of the endocrine milieu. As such, EA is conceived as a key etiological factor underlying a plethora of physiological dysregulations described in the female athlete triad, its male counterpart and the Relative Energy Deficiency in Sport models. Originally developed upon female-specific physiological responses, this concept has recently been extended to males, where experimental evidence is limited. The majority of data for all these models are from cross-sectional or observational studies where hypothesized chronic low energy availability (LEA) is linked to physiological maladaptation. However, the body of evidence determining causal effects of LEA on endocrine, and physiological function through prospective studies manipulating EA is comparatively small, with interventions typically lasting ≤ 5 days. Extending laboratory-based findings to the field requires recognition of the strengths and limitations of current knowledge. To aid this, this review will: (1) provide a brief historical overview of the origin of the concept in mammalian ecology through its evolution of algebraic calculations used in humans today, (2) Outline key differences from the ‘energy balance’ concept, (3) summarise and critically evaluate the effects of LEA on tissues/systems for which we now have evidence, namely: hormonal milieu, reproductive system endocrinology, bone metabolism and skeletal muscle; and finally (4) provide perspectives and suggestions for research upon identified knowledge gaps.

Purpose: Here we assess the feasibility of using machine learning models to non-invasively predict muscle glycogen use during exercise. Methods: Two data sets comprised of: 1. Open-source group data from 166 studies, 2. Manually compiled granular data reported at an individual level from 8 studies published subsequently from the first data set matching the same criteria. The target variable in this study was glycogen use during exercise. Modelling was conducted on the entire data set and on four separate subsets of the data corresponding to different time durations: bands One t ≤ 20min, Two 20 < t ≤ 40min, Three 40 < t ≤ 80min, and Four t > 80min. A baseline Linear Regressor model was used for reference and four models were compared to the performance of the baseline: polynomial Support Vector Regressor (pSVR), Gradient Boosting Regressor (GBR), Random Forest Regressor (RFR) and Voting Regressor. Time band models were evaluated using 3-fold cross validation. Results: Baseline glycogen was identified as the most important variable influencing glycogen delta in all time bands. The best performing models were pSVR in band One, Voting Regressor in band Two, GBR in band Three and Linear and Voting Regressors in band Four. The magnitude of errors made by models increased with time band, from Mean Absolute Error (MAE) of 41 mmol·kg-1 in band One, to MAE of 55 mmol·kg-1 in band Four. Conclusion: We present novel predictive models for estimating glycogen utilization during exercise. Our analysis demonstrates the need for individual models for specific exercise durations.

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 to resting metabolic rate (RMR) (1700 kcal·day) (Phase 1), 5 days of reduced EI (1200-300 kcal·day) prior to weigh-in (Phase 2) and one week of ad libitum EI post-competition (Phase 3). EA fluctuated day by day due to variations in exercise energy expenditure. Regular assessments of body composition, RMR, cardiac function, cardiorespiratory capacity, strength & power, psychological state and blood clinical chemistry for endocrine, bone turnover, hydration, electrolyte, renal, liver and lipid profiles were performed. RESULTS: BM was reduced over the 8 week period by 13.5% (72.5 to 62.7 kg). No consequences of Male Athlete Triad or RED-S were evident during phase 1, where mean daily EA equated to 20 kcal·kg·FFM·day (range: 7 to 31 kcal·kg·FFM·day) and BM and fat mass (FM) losses were 6.5 and 4.4 kg, respectively. However, consequences did present in phase 2 when mean daily EA was consistently

The present study compared the effects of postexercise carbohydrate plus protein (CHO+PROT) and carbohydrate (CHO)-only supplementation on muscle glycogen metabolism, anabolic cell signaling, and subsequent exercise performance. Nine endurance-trained males cycled twice to exhaustion (muscle glycogen decreased from ~495 to ~125 mmol/kg dry wt) and received either CHO only (1.2 g·kg-1·h-1) or CHO+PROT (0.8/0.4 g·kg-1·h-1) during the first 90 min of recovery. Glycogen content was similar before the performance test after 5 h of recovery. Glycogen synthase (GS) fractional activity increased after exhaustive exercise and remained activated 5 h after, despite substantial glycogen synthesis (176.1 ± 19.1 and 204.6 ± 27.0 mmol/kg dry wt in CHO and CHO+PROT, respectively; P = 0.15). Phosphorylation of GS at site 3 and site 2+2a remained low during recovery. After the 5-h recovery, cycling time to exhaustion was improved by CHO+PROT supplementation compared with CHO supplementation (54.6 ± 11.0 vs. 46.1 ± 9.8 min; P = 0.009). After the performance test, muscle glycogen was equally reduced in CHO+PROT and CHO. Akt Ser473 and p70s6k Thr389 phosphorylation was elevated after 5 h of recovery. There were no differences in Akt Ser473, p70s6k Thr389, or TSC2 Thr1462 phosphorylation between treatments. Nitrogen balance was positive in CHO+PROT (19.6 ± 7.6 mg nitrogen/kg; P = 0.04) and higher than CHO (-10.7 ± 6.3 mg nitrogen/kg; P = 0.009). CHO+PROT supplementation during exercise recovery improved subsequent endurance performance relative to consuming CHO only. This improved performance after CHO+PROT supplementation could not be accounted for by differences in glycogen metabolism or anabolic cell signaling, but may have been related to differences in nitrogen balance.NEW & NOTEWORTHY Endurance athletes competing consecutive days need optimal dietary intake during the recovery period. We report that coingestion of protein and carbohydrate soon after exhaustive exercise, compared with carbohydrate only, resulted in better performance the following day. The better performance after coingestion of protein and carbohydrate was not associated with a higher rate of glycogen synthesis or activation of anabolic signaling compared with carbohydrate only. Importantly, nitrogen balance was positive after coingestion of protein and carbohydrate, which was not the case after intake of carbohydrate only, suggesting that protein synthesis contributes to the better performance the following day.

The purpose of this case study was to evaluate the benefits that evidence-based nutritional and training recommendations could have on the time course of reconditioning following hip arthroplasty in a competitive master triathlete. Methods: During 38 weeks (from 6 weeks prior to surgery through to the return to competition), the athlete was provided with detailed training and nutritional recommendations based on the latest research evidence. Dietary intake (via the remote food photographic method), body composition (via DXA), peak oxygen uptake (VO2peak), peak power output (PPO) and cycling efficiency (GE) were assessed 6 weeks pre- and 8, 12, 18, 21 and 25-weeks post-surgery. Training load was quantified (TRIMP score) daily during the retraining. Results: Total body mass increased by 8.2 kg (attributable to a 3.5 and 4.6 kg increase in fat mass and lean mass, respectively) between week -6 and week 8 despite a reduction in carbohydrate (CHO) intake post-surgery (

Purpose: We determined the effect of suppressing lipolysis via administration of Nicotinic acid (NA) and pre-exercise feeding on rates of whole-body substrate utilisation and cycling time trial (TT) performance. Methods: In a randomised, single-blind, crossover design, eight trained male cyclists/triathletes completed two series of TTs in which they performed a predetermined amount of work calculated to last ~60, 90 and 120 min. TTs were undertaken after a standardised breakfast (2 g kg−1 BM of carbohydrate (CHO)) and ingestion of capsules containing either NA or placebo (PL). Results: Plasma [free fatty acids] were suppressed with NA, but increased in the later stages of TT90 and TT120 with PL (p < 0.05). There was no treatment effect on time to complete TT60 (60.4 ± 4.1 vs. 59.3 ± 3.4 min) or TT90 (90.4 ± 9.1 vs. 89.5 ± 6.6 min) for NA and PL, respectively. However, TT120 was slower with NA (123.1 ± 5.7 vs. 120.1 ± 8.7 min, p < 0.001), which coincided with a decline in plasma [glucose] during the later stages of this ride (p < 0.05). For TTs of the same duration, the rates of whole-body CHO oxidation were unaffected by NA, but decreased with increasing TT time (p < 0.05). CHO was the predominant substrate for all TTs contributing between 83 and 94 % to total energy expenditure, although there was a small use of lipid-based fuels for all rides. Conclusion: (1) NA impaired cycling TT performance lasting 120 min, (2) cycling TTs lasting from 60 to 120 min are CHO dependent, and (3) there is an obligatory use of lipid-based fuels in TTs lasting 1–2 h.

Objectives To determine if a 4 d period of high carbohydrate intake can supercompensate muscle glycogen and exercise work capacity on back-to-back occasions. Design Seven trained cyclists (6 male, VO2peak: 57 ± 4 mL kg−1 min−1) completed a 9-d experimental period, consisting of three intermittent exhaustive cycling trials on days 1 (trial 1), 5 (trial 2) and 9 (trial 3). Following trial 1 cyclists were fed a high carbohydrate diet (˜10 g kg−1 day−1) for eight days to assess their capacity to repeatedly supercompensate muscle glycogen with 4 d recovery. Methods A resting muscle biopsy was obtained prior to each trial consisting of 2 min work intervals (90–60% peak power output) interspersed with 2 min recovery (40% peak power output) repeated until exhaustion. Each 72-h period between trial days included two days of low volume cycling and a rest day. Resting muscle glycogen and total work completed was determined for each trial day. Results Baseline muscle glycogen on day 1 (583.6 ± 111.0 mmol kg−1 dry mass) was supercompensated on day 5 (835.1 ± 112.8 mmol kg−1 dry mass; p = 0.04, d = 2.25) and again on day 9 (848.3 ± 111.4 mmol kg−1 dry mass; p = 0.01, d = 2.38). Total cycling work capacity increased from trial 1 to trial 2 (+8.7 ± 5.4 kJ kg−1; p = 0.01; d = 1.41); a large effect was observed in trial 3 compared to trial 1 (+6.4 ± 6.8 kJ kg−1; p = 0.10; d = 1.10). Conclusions A 4 d high carbohydrate feeding strategy is sufficient to repeatedly supercompensate muscle glycogen content following exhaustive exercise and results in enhanced work capacity.

Skeletal muscle glycogen is an important energy source for muscle contraction and a key regulator of metabolic responses to exercise. Manipulation of muscle glycogen is therefore a strategy to improve performance in competitions and potentially adaptation to training. However, assessing muscle glycogen in the field is impractical, and there are no normative values for glycogen concentration at rest and during exercise. The objective of this study was to meta-analyse the effects of fitness, acute dietary carbohydrate (CHO) availability and other factors on muscle glycogen concentration at rest and during exercise of different durations and intensities. PubMed was used to search for original articles in English published up until February 2018. Search terms included muscle glycogen and exercise, filtered for humans. The analysis incorporated 181 studies of continuous or intermittent cycling and running by healthy participants, with muscle glycogen at rest and during exercise determined by biochemical analysis of biopsies. Resting muscle glycogen was determined with a meta-regression mixed model that included fixed effects for fitness status [linear, as maximal oxygen uptake ( $$\dot{V}$$ O2max) in mL·kg−1·min−1] and CHO availability (three levels: high, ≥ 6 g·kg−1 of CHO per day for ≥ 3 days or ≥ 7 g·kg−1 CHO per day for ≥ 2 days; low, glycogen depletion and low-CHO diet; and normal, neither high nor low, or not specified in study). Muscle glycogen during exercise was determined with a meta-regression mixed model that included fixed effects for fitness status, resting glycogen [linear, in mmol·kg−1 of dry mass (DM)], exercise duration (five levels, with means of 5, 23, 53 and 116 min, and time to fatigue), and exercise intensity (linear, as percentage of $$\dot{V}$$ O2max); intensity, fitness and resting glycogen were interacted with duration, and there were also fixed effects for exercise modes, CHO ingestion, sex and muscle type. Random effects in both models accounted for between-study variance and within-study repeated measurement. Inferences about differences and changes in glycogen were based on acceptable uncertainty in standardised magnitudes, with thresholds for small, moderate, large and very large of 25, 75, 150 and 250 mmol·kg−1 of DM, respectively. The resting glycogen concentration in the vastus lateralis of males with normal CHO availability and $$\dot{V}$$ O2max (mean ± standard deviation, 53 ± 8 mL·kg−1·min−1) was 462 ± 132 mmol·kg−1. High CHO availability was associated with a moderate increase in resting glycogen (102, ± 47 mmol·kg−1; mean ± 90% confidence limits), whereas low availability was associated with a very large decrease (− 253, ± 30 mmol·kg−1). An increase in $$\dot{V}$$ O2max of 10 mL·kg−1·min−1 had small effects with low and normal CHO availability (29, ± 44 and 67, ± 15 mmol·kg-1, respectively) and a moderate effect with high CHO availability (80, ± 40 mmol·kg−1). There were small clear increases in females and the gastrocnemius muscle. Clear modifying effects on glycogen utilisation during exercise were as follows: a 30% $$\dot{V}$$ O2max increase in intensity, small (41, ± 20 mmol·kg−1) at 5 min and moderate (87–134 mmol·kg−1) at all other timepoints; an increase in baseline glycogen of 200 mmol·kg−1, small at 5–23 min (28–59 mmol·kg−1), moderate at 116 min (104, ± 15 mmol·kg−1) and moderate at fatigue (143, ± 33 mmol·kg−1); an increase in $$\dot{V}$$ O2max of 10 mL·kg−1·min−1, mainly clear trivial effects; exercise mode (intermittent vs. continuous) and CHO ingestion, clear trivial effects. Small decreases in utilisation were observed in females (vs. males: − 30, ± 29 mmol·kg−1), gastrocnemius muscle (vs. vastus lateralis: − 31, ± 46 mmol·kg−1) and running (vs. cycling: − 70, ± 32 mmol·kg−1). Dietary CHO availability and fitness are important factors for resting muscle glycogen. Exercise intensity and baseline muscle glycogen are important factors determining glycogen use during exercise, especially with longer exercise duration. The meta-analysed effects may be useful normative values for prescription of endurance exercise.

to the editor: It was with great interest that we read the recent article by Goncalves et al. ([2][1]). Given the Journal of Applied Physiology ’s reputation for quality and the forthright title, we anticipated a significant advance in our understanding. Indeed, the study displays high standards

Introduction: Yerba Mate (YM) is a South American plant, rich in polyphenols, saponins, and xanthines, of growing scientific interest because of its metabolic effects. YM has been shown to increase fat utilization during exercise in untrained humans, but its effects on well-trained individuals during exercise are unknown. Methods: We characterized metabolic and physical performance effects of YM in 11 well-trained male cyclists. In a double-blind crossover design, participants ingested 5 g of YM or placebo (PL; maltodextrin) daily for 5 d and 1 h before experimental trials. Results: Ergometer-based tests included a submaximal step test (SST) at 30%–80% of V˙O2max (6 × 5-min stages), followed by a cycloergometer-based time trial (TT) test to complete mechanical work (~30 min; n = 9). Before and during tests, blood and respiratory gas samples were collected. YM increased resting plasma adrenaline concentration (P = 0.002), and fat utilization by 23% at 30%–50% V˙O2max versus PL (Glass effect sizes (ES) ± 95% confidence interval (CI), 0.8 ± 0.55) correlating strongly with post-SST plasma (glycerol; r = 0.758). Treatment effects on rates of perceived exertion, heart rate, and gross efficiency were unclear during SST. Respiratory exchange ratio during TT indicated carbohydrate dependence and did not differ between treatments (PL, 0.95 ± 0.03 (SD); YM, 0.95 ± 0.02). TT performance showed a small (ES = 0.38 ± 0.33) but significant (P = 0.0278) improvement with YM (PL, 30.1 ± 1.8 min (SD); YM, 29.4 ± 1.4 min; 2.2% ± 2% (95% CI)), with an average increase of 7-W power output (ES = 0.2 ± 0.19; P = 0.0418; 2.3% ± 2% (95% CI)) and 2.8% V˙O2 (P = 0.019). Pacing displayed lower power output after 30% of total TT workload in PL vs YM. Conclusions: YM increased fat utilization during submaximal exercise and improved TT performance, but performance-enhancement effect was unrelated to measures of substrate metabolism during maximal exercise.

Autophagy contributes to remodeling of skeletal muscle and is sensitive to contractile activity and prevailing energy availability. We investigated changes in targeted genes and proteins with roles in autophagy following 5 days of energy balance (EB), energy deficit (ED), and resistance exercise (REX) after ED. Muscle biopsies from 15 subjects (8 males, 7 females) were taken at rest following 5 days of EB [45 kcal·kg fat free mass (FFM)−1·day−1] and 5 days of ED (30 kcal·kg FFM−1·day−1). After ED, subjects completed a bout of REX and consumed either placebo (PLA) or 30 g whey protein (PRO) immediately postexercise. Muscle biopsies were obtained at 1 and 4 h into recovery in each trial. Resting protein levels of autophagy-related gene protein 5 (Atg5) decreased after ED compared with EB (∼23%, P < 0.001) and remained below EB from 1 to 4 h postexercise in PLA (∼17%) and at 1 h in PRO (∼18%, P < 0.05). In addition, conjugated Atg5 (cAtg12) decreased below EB in PLA at 4 h (∼20, P < 0.05); however, its values were increased above this time point in PRO at 4 h alongside increases in FOXO1 above EB (∼22–26%, P < 0.05). Notably, these changes were subsequent to increases in unc-51-like kinase 1Ser757phosphorylation (∼60%) 1 h postexercise in PRO. No significant changes in gene expression of selected autophagy markers were found, but EGR-1 increased above ED and EB in PLA (∼417–864%) and PRO (∼1,417–2,731%) trials 1 h postexercise ( P < 0.001). Postexercise protein availability, compared with placebo, can selectively promote autophagic responses to REX in ED.