Substituting carbohydrate at lunch for added protein increases fat oxidation during subsequent exercise in healthy males.

CONTEXT: How pre-exercise meal composition influences metabolic and health responses to exercise later in the day is currently unclear. OBJECTIVE: Examine the effects of substituting carbohydrate for protein at lunch on subsequent exercise metabolism, appetite, and energy intake. METHODS: Twelve healthy males completed three trials in randomized, counterbalanced order. Following a standardized breakfast (779 ± 66 kcal; ∼08:15), participants consumed a lunch (1186 ± 140 kcal; ∼13:15) containing either 0.2 g·kg-1 carbohydrate and ∼2 g·kg-1 protein (LO-CARB), 2 g·kg-1 carbohydrate and ∼0.4 g·kg-1 protein (HI-CARB), or fasted (FAST). Participants later cycled at ∼60% V̇O2peak for 1 h (∼16:15) and post-exercise ad-libitum energy intake was measured (∼18:30). Substrate oxidation, subjective appetite, and plasma concentrations of glucose, insulin, non-esterified fatty acids (NEFA), peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and acylated ghrelin (AG) were measured for 5 h post-lunch. RESULTS: Fat oxidation was greater during FAST (+11.66 ± 6.63 g) and LO-CARB (+8.00 ± 3.83 g) than HI-CARB (p < 0.001), with FAST greater than LO-CARB (+3.67 ± 5.07 g; p < 0.05). NEFA were lowest in HI-CARB and highest in FAST, with insulin demonstrating the inverse response (all p < 0.01). PYY and GLP-1 demonstrated a stepwise pattern, with LO-CARB greatest and FAST lowest (all p < 0.01). AG was lower during HI-CARB and LO-CARB versus FAST (p < 0.01). Energy intake in LO-CARB was lower than FAST (-383 ± 233 kcal; p < 0.001) and HI-CARB (-313 ± 284 kcal; p < 0.001). CONCLUSION: Substituting carbohydrate for protein in a pre-exercise lunch increased fat oxidation, suppressed subjective and hormonal appetite, and reduced post-exercise energy intake.

Genetic Associations With Acceleration, Change of Direction, Jump Height, and Speed in English Academy Football Players.

ABSTRACT: McAuley, ABT, Hughes, DC, Tsaprouni, LG, Varley, I, Suraci, B, Bradley, B, Baker, J, Herbert, AJ, and Kelly, AL. Genetic associations with acceleration, change of direction, jump height, and speed in English academy football players. J Strength Cond Res 38(2): 350-359, 2024-High-intensity movements and explosive actions are commonly assessed during athlete development in football (soccer). Although many environmental factors underpin these power-orientated traits, research suggests that there is also a sizeable genetic component. Therefore, this study examined the association of 22 single-nucleotide polymorphisms (SNPs) with acceleration, change of direction, jump height, and speed in academy football players. One hundred and forty-nine, male, under-12 to under-23 football players from 4 English academies were examined. Subjects performed 5-, 10-, 20-, and 30-m sprints, countermovement jumps (CMJs), and the 5-0-5 agility test. Simple linear regression was used to analyze individual SNP associations, whereas both unweighted and weighted total genotype scores (TGS; TWGS) were computed to measure the combined influence of all SNPs. To control for multiple testing, a Benjamini-Hochberg false discovery rate of 0.05 was applied to all genotype model comparisons. In isolation, the GALNT13 (rs10196189) G allele and IL6 (rs1800795) G/G genotype were associated with faster (∼4%) 5-, 10-, and 20-m sprints and higher (∼16%) CMJs, respectively (p < 0.001). Furthermore, the TGS and TWGS significantly correlated with all performance assessments, explaining between 6 and 33% of the variance (p < 0.001). This study demonstrates that some genetic variants are associated with power-orientated phenotypes in youth football players and may add value toward a future polygenic profile of physical performance.

Combined Turmeric, Vitamin C, and Vitamin D Ready-to-Drink Supplements Reduce Upper Respiratory Illness Symptoms and Gastrointestinal Discomfort in Elite Male Football Players.

Elite football is associated with the increased risk of illness, although targeted supplementation can reduce illness risk. This study assessed the effects of a supplement containing turmeric root within a black pepper and fat-soluble blend, vitamin C and vitamin D, on upper respiratory symptoms (URS), gastrointestinal symptoms (GIS), muscle soreness, and markers of inflammation and gut permeability in elite male footballers. Twenty-three footballers completed 3 weeks of no intervention (CON), followed by 16 weeks of daily consuming 60 mL of a commercially available supplement containing raw turmeric root (17.5 g, estimated to contain 700 mg of curcumin), vitamin C (1000 mg), and vitamin D3 (3000 IU/75 mcg) (SUP). URS and GIS were measured daily. Immediately (0 h), 40, and 64 h after six competitive matches (two in CON, four in SUP), the subjective soreness and plasma concentrations of creatine kinase [CK], c-reactive protein [CRP], and intestinal fatty-acid binding protein [I-FABP] were assessed. URS incidence (p < 0.001), GIS (p < 0.05), and plasma [I-FABP] at 0 h (p < 0.05) were greater during CON versus SUP. At 40 h, [CRP] was greater than 0 h during CON (p < 0.01) but not SUP (p = 0.204). There were no differences in soreness or [CK]. This study indicates that turmeric root, vitamin C, and vitamin D supplementation over 16 weeks can reduce URS, GIS, and post-match [I-FABP] in elite footballers.

P1NP and ß-CTX-1 Responses to a Prolonged, Continuous Running Bout in Young Healthy Adult Males: A Systematic Review with Individual Participant Data Meta-analysis.

BACKGROUND: Circulating biomarkers of bone formation and resorption are widely used in exercise metabolism research, but their responses to exercise are not clear. This study aimed to quantify group responses and inter-individual variability of P1NP and ß-CTX-1 after prolonged, continuous running (60-120 min at 65-75% V̇O2max) in young healthy adult males using individual participant data (IPD) meta-analysis. METHODS: The protocol was designed following PRISMA-IPD guidelines and was pre-registered on the Open Science Framework prior to implementation ( https://osf.io/y69nd ). Changes in P1NP and ß-CTX-1 relative to baseline were measured during, immediately after, and in the hours and days following exercise. Typical hourly and daily variations were estimated from P1NP and ß-CTX-1 changes relative to baseline in non-exercise (control) conditions. Group responses and inter-individual variability were quantified with estimates of the mean and standard deviation of the difference, and the proportion of participants exhibiting an increased response. Models were conducted within a Bayesian framework with random intercepts to account for systematic variation across studies. RESULTS: P1NP levels increased during and immediately after running, when the proportion of response was close to 100% (75% CrI: 99 to 100%). P1NP levels returned to baseline levels within 1 h and over the next 4 days, showing comparable mean and standard deviation of the difference with typical hourly (0.1 ± 7.6 ng·mL-1) and daily (- 0.4 ± 5.7 ng·mL-1) variation values. ß-CTX-1 levels decreased during and up to 4 h after running with distributions comparable to typical hourly variation (- 0.13 ± 0.11 ng·mL-1). There was no evidence of changes in ß-CTX-1 levels during the 4 days after the running bout, when distributions were also similar between the running data and typical daily variation (- 0.03 ± 0.10 ng·mL-1). CONCLUSION: Transient increases in P1NP were likely biological artefacts (e.g., connective tissue leakage) and not reflective of bone formation. Comparable small decreases in ß-CTX-1 identified in both control and running data, suggested that these changes were due to the markers' circadian rhythm and not the running intervention. Hence, prolonged continuous treadmill running did not elicit bone responses, as determined by P1NP and ß-CTX-1, in this population.

Maturity-Associated Polygenic Profiles of under 12-16-Compared to under 17-23-Year-Old Male English Academy Football Players.

The purpose of this study was to examine polygenic profiles previously associated with maturity timing in male academy football players across different age phases. Thus, 159 male football players from four English academies (U12-16, n = 86, aged 13.58 ± 1.58 years; U17-23, n = 73, aged 18.07 ± 1.69 years) and 240 male European controls were examined. Polygenic profiles comprised 39 single nucleotide polymorphisms and were analysed using unweighted and weighted total genotype scores (TGSs; TWGSs). There were significant differences in polygenic profiles between groups, whereby U17-23 players had more genetic variants associated with later maturity compared to U12-16 players (TGS, p = 0.010; TWGS, p = 0.024) and controls (TGS, p = 0.038; TWGS, p = 0.020). More specifically, U17-23 players had over two-times the odds of possessing >36 later-maturing alleles than <30 compared to U12-16 players (odds ratio (OR) = 2.84) and controls (OR = 2.08). These results suggest there was a greater proportion of relatively later-maturing players as maturation plateaus towards adulthood, which may be explained by the 'underdog hypothesis'. This study provides the first known molecular evidence that supports the notion that a maturity selection bias exists within male academy football.

Experiences of Physical Activity, Healthy Eating and Quality of Life During and Following Pregnancy in Overweight and Obese Postpartum Women.

OBJECTIVES: This retrospective study explored the experiences of women with overweight or obesity regarding physical activity, diet and quality of life leading up to, during, and following pregnancy. METHODS: A qualitative descriptive design was adopted, whereby data collected through semi-structured interviews were analysed using thematic analysis. Throughout the interviews, individuals were asked to describe their barriers to a healthy lifestyle during and following pregnancy. RESULTS: Ten women (34.5 ± 5.2 years old, BMI 30.4 ± 3.5 kg·m- 2) who were between 12 and 52 weeks postpartum participated. A range of themes were identified when discussing barriers to physical activity and healthy eating during and following pregnancy. For example, tiredness, especially in the third trimester of pregnancy, and a lack of support at home, was often cited as preventing engagement in exercise and healthy eating practices. A lack of convenience when attending exercise classes, medical complications following the birth and the cost of attending pregnancy-specific classes were identified as barriers to exercise engagement. Cravings and nausea were identified as barriers to healthy eating during pregnancy. Quality of life was positively associated with exercise and healthy eating, whilst a lack of sleep, loneliness and a loss of freedom since the baby had arrived negatively influenced quality of life. DISCUSSION: Postpartum women with overweight and obesity experience many barriers when attempting to engage in a healthy lifestyle during and following pregnancy. These findings can be used to inform the design and delivery of future lifestyle interventions in this population.

Turmeric supplementation improves markers of recovery in elite male footballers: a pilot study.

Football match-play causes muscle damage and provokes an inflammatory response. Rapid recovery is paramount to optimising subsequent performance and reducing injury risk. Turmeric contains high concentrations of curcumin, a polyphenol that has been shown to reduce muscle damage and soreness post-exercise in recreational exercisers. However, it is unknown whether a curcumin-containing supplement can support elite footballers recovery between matches. This applied study explored whether a turmeric supplement could improve performance, subjective and physiological markers of recovery, in elite male footballers. Twenty-four elite male footballers divided into a turmeric group, who consumed 60 mL of a turmeric drink twice per day, or a control group who did not. After 96 h of rest, baseline measurements of subjective soreness (leg and whole-body), plasma creatine kinase ([CK]), plasma C-reactive protein ([CRP]), isometric mid-thigh pull (IMTP) and counter movement jump (CMJ), were collected. Following eight competitive matches, subjective leg and whole-body soreness and plasma concentrations of inflammation markers ([CK] and [CRP]) were assessed immediately (0 h), 40 and 64 h post-match. Performance markers (IMTP and CMJ) were also assessed at 40 and 64 h post-match. Percentage change from baseline showed a main effect of group (p = 0.035, p = 0.005) and time (p = 0.002, p = 0.002) for both leg and whole-body soreness, respectively. There was a group by time interaction effect (p = 0.049) for [CRP]. There were no effects of turmeric on [CK], CMJ or IMTP. This applied study is the first in elite footballers to show that a curcumin-containing supplementation may attenuate a biomarker of inflammation [CRP] and soreness post-match play.

Perspectives from research and practice: A survey on external load monitoring and bone in sport.

Introduction: There is limited information regarding the association between external load and estimated bone load in sport, which may be important due to the influence exercise can have on bone accrual and injury risk. The aim of this study was to identify external load measuring tools used by support staff to estimate bone load and assess if these methodologies were supported in research. Methods: A survey was comprised of 19 multiple choice questions and the option to elaborate on if/how they monitor external load and if/how they used them to estimate bone load. A narrative review was performed to assess how external load is associated to bone in research. Results: Participants were required to be working as support staff in applied sport. Support staff (n = 71) were recruited worldwide with the majority (85%) working with professional elite athletes. 92% of support staff monitored external load in their organisation, but only 28% used it to estimate bone load. Discussion: GPS is the most commonly used method to estimate bone load, but there is a lack of research assessing GPS metrics with bone load. Accelerometry and force plates were among the most prevalent methods used to assess external load, but a lack of bone specific measurements were reported by support staff. Further research exploring how external load relates to bone is needed as there is no consensus on which method of external load is best to estimate bone load in an applied setting.

Relationship between Football-Specific Training Characteristics and Tibial Bone Adaptation in Male Academy Football Players.

We examined the relationship between football-specific training and changes in bone structural properties across a 12-week period in 15 male football players aged 16 years (Mean ± 1 SD = 16.6 ± 0.3 years) that belonged to a professional football academy. Tibial scans were performed at 4%, 14% and 38% sites using peripheral quantitative computed tomography immediately before and 12 weeks after increased football-specific training. Training was analysed using GPS to quantify peak speed, average speed, total distance and high-speed distance. Analyses were conducted with bias-corrected and accelerated bootstrapped 95% confidence intervals (BCa 95% CI). There were increases in bone mass at the 4% (mean ∆ = 0.15 g, BCa 95% CI = 0.07, 0.26 g, g = 0.72), 14% (mean ∆ = 0.04 g, BCa 95% CI = 0.02, 0.06 g, g = 1.20), and 38% sites (mean ∆ = 0.03 g, BCa 95% CI = 0.01, 0.05 g, g = 0.61). There were increases in trabecular density (4%), (mean ∆ = 3.57 mg·cm-3, BCa 95% CI = 0.38, 7.05 mg·cm-3, g = 0.53), cortical dentsity (14%) (mean ∆ = 5.08 mg·cm-3, BCa 95% CI = 0.19, 9.92 mg·cm-3, g = 0.49), and cortical density (38%) (mean ∆ = 6.32 mg·cm-3, BCa 95% CI = 4.31, 8.90 mg·cm-3, g = 1.22). Polar stress strain index (mean ∆ = 50.56 mm3, BCa 95% CI = 10.52, 109.95 mm3, g = 0.41), cortical area (mean ∆ = 2.12 mm2, BCa 95% CI = 0.09, 4.37 mm2, g = 0.48) and thickness (mean ∆ = 0.06 mm, BCa 95% CI = 0.01, 0.13 mm, g = 0.45) increased at the 38% site. Correlations revealed positive relationships between total distance and increased cortical density (38%) (r = 0.39, BCa 95% CI = 0.02, 0.66), and between peak speed and increased trabecular density (4%) (r = 0.43, BCa 95% CI = 0.03, 0.73). There were negative correlations between total (r = -0.21, BCa 95% CI = -0.65, -0.12) and high-speed distance (r = -0.29, BCa 95% CI = -0.57, -0.24) with increased polar stress strain index (38%). Results suggest that despite football training relating to increases in bone characteristics in male academy footballers, the specific training variables promoting adaptation over a 12-week period may vary. Further studies conducted over a longer period are required to fully elucidate the time-course of how certain football-specific training characteristics influence bone structural properties.

Intermittent fasting and bone health: a bone of contention?

Intermittent fasting (IF) is a promising strategy for weight loss and improving metabolic health, but its effects on bone health are less clear. This review aims to summarise and critically evaluate the preclinical and clinical evidence on IF regimens (the 5:2 diet, alternate-day fasting (ADF) and time-restricted eating (TRE)/time-restricted feeding and bone health outcomes. Animal studies have utilised IF alongside other dietary practices known to elicit detrimental effects on bone health and/or in models mimicking specific conditions; thus, findings from these studies are difficult to apply to humans. While limited in scope, observational studies suggest a link between some IF practices (e.g. breakfast omission) and compromised bone health, although lack of control for confounding factors makes these data difficult to interpret. Interventional studies suggest that TRE regimens practised up to 6 months do not adversely affect bone outcomes and may even slightly protect against bone loss during modest weight loss (< 5 % of baseline body weight). Most studies on ADF have shown no adverse effects on bone outcomes, while no studies on the '5­2' diet have reported bone outcomes. Available interventional studies are limited by their short duration, small and diverse population samples, assessment of total body bone mass exclusively (by dual-energy X-ray absorptiometry) and inadequate control of factors that may affect bone outcomes, making the interpretation of existing data challenging. Further research is required to better characterise bone responses to various IF approaches using well-controlled protocols of sufficient duration, adequately powered to assess changes in bone outcomes and designed to include clinically relevant bone assessments.

Genetic associations with technical capabilities in English academy football players: a preliminary study.

BACKGROUND: Technical capabilities have significant discriminative and prognostic power in youth football. Although, many factors influence technical performance, no research has explored the genetic contribution. As such, the purpose of this study was to examine the association of several single nucleotide polymorphisms (SNPs) with technical assessments in youth football players. METHODS: Fifty-three male under-13 to under-18 outfield football players from two Category 3 English academies were genotyped for eight SNPs. Objective and subjective technical performance scores in dribbling, passing, and shooting were collated. Simple linear regression was used to analyse individual SNP associations each variable, whereas both unweighted and weighted total genotype scores (TGSs; TWGSs) were computed to measure the combined influence of all SNPs. RESULTS: In isolation, the ADBR2 (rs1042714) C allele, BDNF (rs6265) C/C genotype, DBH (rs1611115) C/C genotype, and DRD1 (rs4532) C allele were associated with superior (8-10%) objective dribbling and/or shooting performance. The TGSs and/or TWGSs were significantly correlated with each technical assessment (except subjective passing), explaining up to 36% and 40% of the variance in the objective and subjective assessments, respectively. CONCLUSIONS: The results of this study suggest inter-individual genetic variation may influence the technical capabilities of youth football players and proposes several candidate SNPs that warrant further investigation.

External training load is associated with adaptation in bone and body composition over the course of a season in elite male footballers.

This study examined the relationship between training load and changes in body composition and bone characteristics across a competitive season. Twenty senior male professional football players participated in this prospective longitudinal study. Participants underwent dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) scans on four occasions across the study period, resulting in three phases of the season. Phase 1 (Scan 1-Scan 2: 6-weeks: pre-season), Phase 2 (Scan 2-Scan 3: 24-weeks: first part of the season), and Phase 3 (Scan 3-Scan 4: 13-weeks: second part of the season). External training load was quantified using GPS devices. In Phase 1 there was a significant increase (mean ± SE) in lean mass (from 66.0 ± 1.4 to 67.8 ± 1.4 kg) and a significant decrease in fat mass (from 11.5 ± 0.6 to 10.4 ± 0.6 kg). In Phase 2 there were significant increases in whole-body BMD (from 1.41 ± 0.02 to 1.43 ± 0.02 g/cm2), leg (from 1563 ± 43 to 1572 ± 43 g) and whole-body BMC (from 3807 ± 100 to 3860 ± 100 g), tibial mass (14 % site) (from 3.72 ± 0.08 to 3.74 ± 0.08 g), tibial strength (SSI(POL)14 % site) (from 2331 ± 78 to 2378 ± 78 mm3), and tibial density (4 % site) (from 382 ± 8 to 388 ± 8 mm3). In Phase 3, there was a significant decrease in tibial mass (14 % site) (from 3.74 ± 0.08 to 3.72 ± 0.08 g). Bootstrapped (BCa 95 % CI) Pearson correlations showed that in Phase 2 there were significant positive relationships between the increases in leg BMC and total distance (r = 0.44, 0.01-0.80), accelerations (r = 0.45, 0.08-0.75), and decelerations (r = 0.49, 0.07-0.83), and between the increase in tibial strength (SSI(POL)14 % site) and accelerations (r = 0.53, 0.19-0.80). High magnitude dynamic actions, such as accelerations and decelerations were positively correlated with changes in bone characteristics during a professional football season and should be considered by practitioners when prescribing exercise to induce bone adaptation.

Effects of Morning Vs. Evening exercise on appetite, energy intake, performance and metabolism, in lean males and females.

Exercise is an important component of a weight management strategy. However, little is known about whether circadian variations in physiological and behavioural processes can influence the appetite and energy balance responses to exercise performed at different times of the day. This study compared the effects of morning and evening exercise on appetite, post-exercise energy intake, and voluntary performance. In randomised, counterbalanced order, 16 healthy males and females (n = 8 each) completed two trials, performing morning exercise at 10:30 (AMEx) or evening exercise at 18:30 (PMEx). Exercise consisted of 30 min steady-state cycling (60% V˙ O2peak), and a 15-min performance test. A standardised meal (543 ± 86 kcal) was consumed 2-h before exercise and ad-libitum energy intake was assessed 15 min after exercise, with subjective appetite measured throughout. Absolute ad-libitum energy intake was 152 ± 126 kcal greater during PMEx (P < 0.001), but there was no differences in subjective appetite between trials immediately pre-exercise, or immediately before the post-exercise meal (P ≥ 0.060). Resting energy expenditure (P < 0.01) and carbohydrate oxidation (P < 0.05) were greater during AMEx, but there were no differences in substrate oxidation or energy expenditure during exercise (P ≥ 0.155). Exercise performance was not different between trials (P = 0.628). In conclusion, acute morning and evening exercise prompt similar appetite responses, but post-exercise ad-libitum energy intake is greater following evening exercise. These findings demonstrate discordant responses between subjective appetite and ad-libitum energy intake but suggest that exercise might offset circadian variations in appetite. Longer-term studies are required to determine how exercise timing affects adherence and weight management outcomes to exercise interventions. TRIAL REGISTRATION: NCT04742530, February 8, 2021.

Genetic Variations between Youth and Professional Development Phase English Academy Football Players.

The purpose of this study was to examine differences in the genotype frequency distribution of thirty-three single nucleotide variants (SNVs) between youth development phase (YDP) and professional development phase (PDP) academy football players. One hundred and sixty-six male football players from two Category 1 and Category 3 English academies were examined within their specific age phase: YDP (n = 92; aged 13.84 ± 1.63 years) and PDP (n = 74; aged 18.09 ± 1.51 years). Fisher's exact tests were used to compare individual genotype frequencies, whereas unweighted and weighted total genotype scores (TGS; TWGS) were computed to assess differences in polygenic profiles. In isolation, the IL6 (rs1800795) G allele was overrepresented in PDP players (90.5%) compared to YDP players (77.2%; p = 0.023), whereby PDP players had nearly three times the odds of possessing a G allele (OR = 2.83, 95% CI: 1.13-7.09). The TGS (p = 0.001) and TWGS (p < 0.001) were significant, but poor, in distinguishing YDP and PDP players (AUC = 0.643-0.694), with PDP players exhibiting an overall more power-orientated polygenic profile. If validated in larger independent youth football cohorts, these findings may have important implications for future studies examining genetic associations in youth football.

Exercise interventions for weight management during pregnancy and up to 1 year postpartum among normal weight women and women with overweight and obesity: An updated systematic review.

Background: Given the increased occurrence of pre-gravid obesity in recent years, and the implications of maternal obesity for maternal and offspring health, it is evident that there is a continued need to investigate antenatal and postnatal weight management strategies and to provide evidence-based advice for exercise-based interventions. Given the small number of studies (n = 5) included in an original systematic review by our group in 2015, it was important to add to the dataset by assessing data published since 2015, in order to provide a more in-depth view of current knowledge. Objective: To provide an updated systematic review on studies employing exercise interventions for weight management in pregnant and postpartum women. Methods: A systematic review of randomised controlled trials evaluating the effects of an exercise intervention on gestational weight gain and postpartum weight management in normal weight women, and women with overweight and obesity was conducted. PubMed, Scopus, Central Register of Controlled Trials and Web of Science were searched for studies published between September 2013 and June 2021. No restrictions were set on type, intensity, duration, or frequency of exercise intervention. Only studies that targeted body weight or mass as a primary outcome were included. Results: Thirteen studies were included in this review: 11 during and two following pregnancy. Exercise significantly reduced gestational weight gain in five of the pregnancy studies and induced significant weight loss in one of the postpartum studies. Across studies, there were large disparities in exercise modality, frequency, and duration, although moderate intensity exercise was consistently employed. Conclusions: Some studies showed positive effects of exercise on weight management during and following pregnancy. While there is still no consensus on effective exercise intervention approaches, it is crucial that physical activity, of any safe form, is recommended to encourage healthy weight management during this time.

Modelling Changes in Bone and Body Composition Over a Season in Elite Male Footballers.

This study investigated the change in bone and body composition characteristics of elite football players and recreationally active control participants across the course of a season. Fortysix participants (20 footballers and 26 recreationally active controls) were assessed by dual-energy x-ray absorptiometry and peripheral Quantitative Computed Tomography for a range of bone and body composition characteristics at four points over the course of a competitive season. Multilevel modelling was used to examine changes. Footballers had higher characteristics than controls for 24 out of 29 dual-energy x-ray absorptiometry and peripheral Quantitative Computed Tomography variables (all p<0.05). However, there was also significant random inter-individual variation in baseline values for all variables, for both footballers and controls (p < 0.05). Wholebody bone mineral density, leg and whole-body bone mineral content, tibial bone mass and area (38%) increased across the season in footballers (p < 0.05), and there was significant random inter-individual variation in the rate of increase of leg and whole-body bone mineral content (p<0.05). Whole-body bone mineral density, leg and whole-body bone mineral content, tibial bone mass and area (38%) increased over the course of the season in elite football players. The modelling information on expected changes in bone characteristics provides practitioners with a method of identifying those with abnormal bone response to football training and match-play.

One week of high-fat overfeeding alters bone metabolism in healthy males: A pilot study.

OBJECTIVES: Short periods of excessive consumption of indulgent high-fat foods are common in Western society, but the effect this has on bone is unknown. The aim of this pilot study was to explore how a 7-d hyperenergetic, high-fat diet affects candidate biomarkers of bone metabolism. METHODS: The study included 12 healthy men with a mean age of 24 y (SD = 4 y) and body mass index (BMI) of 24.1 kg/m2 (SD = 1.5). The men consumed a 7-d hyperenergetic, high-fat diet (HE-HFD; 20.9 [SD = 0.8] MJ; 65% total energy as fat) and a control (CON) diet (10.9 [SD = 2] MJ; 36% total energy as fat), in randomized, crossover order, with each trial separated by 3 wk. Markers of bone formation (P1NP) and bone resorption (CTx) were measured at baseline and after 1, 3, and 7 d of each diet. Bone metabolic responses were analyzed using two-factor repeated-measures analysis of variance and subsequent pairwise comparisons. RESULTS: There was a main effect of time (P < 0.05), but no trial (P = 0.270) or time- × -trial interaction (P = 0.693) effects for plasma concentrations of CTx. Mean CTx concentrations did not differ between trials (CON: 0.97 ng/mL [SD = 0.39]; HE-HFD: 1.03 ng/mL [SD = 0.22]; P = 0.225). There was a main effect of trial (P < 0.01), but no time (P = 0.138) or trial- × -interaction (P = 0.179) effects for plasma concentrations of P1NP. Mean P1NP concentrations were lower during the HE-HFD (61.79 ng/mL [SD = 26.54]) than during the CON diet (77.89 ng/mL [SD = 28.71]; P < 0.01). CONCLUSIONS: A 7-d hyperenergetic, high-fat diet reduces a marker of bone formation but does not affect a marker of bone resorption. This pilot study suggested that short periods of excessive energy and fat consumption may detrimentally affect bone health.

A Systematic Review investigating the Effectiveness of Exercise training in Glycogen Storage Diseases.

Introduction: Glycogen storage diseases (GSDs) are rare inborn errors of carbohydrate metabolism typically with skeletal muscle and liver involvement. In those with skeletal muscle involvement, the majority display symptoms of exercise intolerance which can cause profound exercise limitation and impair everyday living and quality of life (QoL). There are no curative treatments for GSDs, thus therapeutic options, such as exercise training, are aimed at improving QoL by alleviating signs and symptoms. In order to investigate the effectiveness of exercise training in adults with GSDs, we systematically reviewed the literature. Methods: In this review we conducted searches within SCOPUS and MEDLINE to identify potential papers for inclusion. These papers were independently assessed for inclusion and quality by two authors. We identified 23 studies which included aerobic training, strength training or respiratory muscle training in patients with McArdles (n = 41) and Pompe disease (n = 139). Results: In McArdle disease, aerobic exercise training improved aerobic capacity (VO2 peak) by 14-111% with further benefits to functional capacity and well-being. Meanwhile, strength training increased muscle peak power by 100-151% and reduced disease severity. In Pompe disease, a combination of aerobic and strength training improved VO2 peak by 9-10%, muscle peak power by 64%, functional capacity and well-being. Furthermore, respiratory muscle training (RMT) improved respiratory muscular strength [maximum inspiratory pressure (MIP) increased by up to 65% and maximum expiratory pressure (MEP) by up to 70%], with additional benefits shown in aerobic capacity, functional capacity and well-being. Conclusion: This adds to the growing body of evidence which suggests that supervised exercise training is safe and effective in improving aerobic capacity and muscle function in adults with McArdle or Pompe disease. However, the literature base is limited in quality and quantity with a dearth of literature regarding exercise training in other GSD subtypes.

A Systematic Review investigating the Effectiveness of Exercise training in Glycogen Storage Diseases Background: Glycogen storage diseases (GSDs) are a group of rare inherited metabolic disorders typically affecting carbohydrate metabolism within the skeletal muscle and liver. In those where the skeletal muscle is affected, the majority display exercise intolerance which can impact everyday living and quality of life. No curative treatments for GSDs exist, therefore exercise training offers a therapeutic option to reduce symptoms and enhance patient's quality of life. In order to investigate the effectiveness of exercise training as a therapeutic option, we systematically reviewed the literature. Study Characteristics: We found 23 studies which included aerobic training, strength training and respiratory muscle training in adults with certain types of GSD including McArdles (n = 41) and Pompe disease (n = 139). Key Results: In McArdle disease, aerobic exercise improved aerobic performance, with further benefits to functional capacity and well-being. Meanwhile, strength training increased muscular strength and reduced disease severity.In Pompe disease a combination of aerobic and strength training improved aerobic capacity, muscular strength, functional capacity and well-being. Furthermore, respiratory muscle training (RMT) improved the strength of respiratory muscles with further benefits in aerobic capacity, functional capacity and well-being. Implications: This systematic review indicates that supervised exercise training is safe and effective in improving aerobic capacity and muscle function in adults with McArdle or Pompe disease. However, the effectiveness of exercise training in other GSDs is as yet unknown.

Corrigendum: Injury Incidence Across the Menstrual Cycle in International Footballers.

[This corrects the article DOI: 10.3389/fspor.2021.616999.].