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Justin Roberts is an Associate Professor in Health and Exercise Nutrition with a focus on applied and health-based nutrition. His interests encompass a wide range of areas, including how both dietary and nutrient interventions can impact on adaptations to exercise, both in terms of physiological and metabolic health, as well as enhancing recovery. He has a particular interest in the use of ‘calorie restriction mimetic’ nutrients on physiological mechanisms associated with fat oxidation and weight management, as well as the use of protein feeding for exercise adaptations and recovery.
We evaluated the impact of protein supplementation on adaptations to arduous concurrent training in healthy adults with potential applications to individuals undergoing military training. Peer-reviewed papers published in English meeting the population, intervention, comparison and outcome criteria were included. Database searches were completed in PubMed, Web of science and SPORTDiscus. Study quality was evaluated using the COnsensus based standards for the selection of health status measurement instruments checklist. Of 11 studies included, nine focused on performance, six on body composition and four on muscle recovery. Cohen’s d effect sizes showed that protein supplementation improved performance outcomes in response to concurrent training (ES = 0.89, 95% CI = 0.08–1.70). When analysed separately, improvements in muscle strength (SMD = +4.92 kg, 95% CI = −2.70–12.54 kg) were found, but not in aerobic endurance. Gains in fat-free mass (SMD = +0.75 kg, 95% CI = 0.44–1.06 kg) and reductions in fat-mass (SMD = −0.99, 95% CI = −1.43–0.23 kg) were greater with protein supplementation. Most studies did not report protein turnover, nitrogen balance and/or total daily protein intake. Therefore, further research is warranted. However, our findings infer that protein supplementation may support lean-mass accretion and strength gains during arduous concurrent training in physical active populations, including military recruits.
Shaun Chapman; Henry Chung; Alex Rawcliffe; Rachel Izard; Lee Smith; Justin Roberts. Does Protein Supplementation Support Adaptations to Arduous Concurrent Exercise Training? A Systematic Review and Meta-Analysis with Military Based Applications. Nutrients 2021, 13, 1416 .
AMA StyleShaun Chapman, Henry Chung, Alex Rawcliffe, Rachel Izard, Lee Smith, Justin Roberts. Does Protein Supplementation Support Adaptations to Arduous Concurrent Exercise Training? A Systematic Review and Meta-Analysis with Military Based Applications. Nutrients. 2021; 13 (5):1416.
Chicago/Turabian StyleShaun Chapman; Henry Chung; Alex Rawcliffe; Rachel Izard; Lee Smith; Justin Roberts. 2021. "Does Protein Supplementation Support Adaptations to Arduous Concurrent Exercise Training? A Systematic Review and Meta-Analysis with Military Based Applications." Nutrients 13, no. 5: 1416.
The aim of this systematic review and meta-analysis was to identify a list of common, candidate genes associated with the three components of fitness, specifically cardiovascular fitness, muscular strength, and anaerobic power, and how these genes are associated with exercise response phenotype variability, in previously untrained participants. A total of 3,969 potentially relevant papers were identified and processed for inclusion. After eligibility and study selection assessment, 24 studies were selected for meta-analysis, comprising a total of 3,012 participants. Meta-Essentials spreadsheet 1.4 (Microsoft Excel) was used in creating the forest plots and meta-analysis. IBM SPSS statistics V24 was implemented for the statistical analyses and the alpha was set at p ≤ 0.05. 13 candidate genes and their associated alleles were identified, which were associated with the phenotypes of interest. Analysis of training group data showed significant differential phenotypic responses. Subgroup analysis showed; 44%, 72% and 10% of the response variance in aerobic, strength and power phenotypes, respectively, were explained by genetic influences. This analysis established that genetic variability explained a significant proportion of the adaptation differences across the three components of fitness in the participants post-training. The results also showed the importance of analysing and reporting specific gene alleles. Information obtained from these findings has the potential to inform and influence future exercise-related genes and training studies.
Henry C Chung; Don R Keiller; Justin D Roberts; Dan A Gordon. Do exercise-associated genes explain phenotypic variance in the three components of fitness? A Systematic review & Meta-analysis. 2021, 1 .
AMA StyleHenry C Chung, Don R Keiller, Justin D Roberts, Dan A Gordon. Do exercise-associated genes explain phenotypic variance in the three components of fitness? A Systematic review & Meta-analysis. . 2021; ():1.
Chicago/Turabian StyleHenry C Chung; Don R Keiller; Justin D Roberts; Dan A Gordon. 2021. "Do exercise-associated genes explain phenotypic variance in the three components of fitness? A Systematic review & Meta-analysis." , no. : 1.
By using deceptive experiments in which participants are informed that they received caffeine when, in fact, they received an inert substance (i.e., placebo), several investigations have demonstrated that exercise performance can be enhanced to a similar degree as a known caffeine dose. This ‘placebo effect’ phenomenon may be part of the mechanisms explaining caffeine’s ergogenicity in exercise. However, there is no study that has established whether the placebo effect of caffeine is also present for other benefits obtained with acute caffeine intake, such as enhanced fat oxidation during exercise. Therefore, the aim of this investigation was to investigate the placebo effect of caffeine on fat oxidation during exercise. Twelve young men participated in a deceptive double-blind cross-over experiment. Each participant completed three identical trials consisting of a step incremental exercise test from 30 to 80% of V . O2max. In the two first trials, participants ingested either 3 mg/kg of cellulose (placebo) or 3 mg/kg of caffeine (received caffeine) in a randomized order. In the third trial, participants were informed that they had received 3 mg/kg of caffeine, but a placebo was provided (informed caffeine). Fat oxidation rates were derived from stoichiometric equations. In received caffeine, participants increased their rate of fat oxidation over the values obtained with the placebo at 30%, 40%, 50%, and 60% of V . O2max (all p < 0.050). In informed caffeine, participants increased their rate of fat oxidation at 30%, 40%, 50% 60%, and 70% of V . O2max (all p < 0.050) over the placebo, while there were no differences between received versus informed caffeine. In comparison to placebo (0.32 ± 0.15 g/min), the rate of maximal fat oxidation was higher in received caffeine (0.44 ± 0.22 g/min, p = 0.045) and in informed caffeine (0.41 ± 0.20 g/min, p = 0.026) with no differences between received versus informed caffeine. However, the intensity at which maximal fat oxidation rate was obtained (i.e., Fatmax) was similar in placebo, received caffeine, and informed caffeine trials (42.5 ± 4.5, 44.2 ± 9.0, and 41.7 ± 10.5% of V . O2max, respectively, p = 0.539). In conclusion, the expectancy of having received caffeine produced similar effects on fat oxidation rate during exercise than actually receiving caffeine. Therefore, the placebo effect of caffeine is also present for the benefits of acute caffeine intake on substrate oxidation during exercise and it may be used to enhance fat oxidation during exercise in participants while reducing any risks to health that this substance may have.
Jorge Gutiérrez-Hellín; Carlos Ruiz-Moreno; Millán Aguilar-Navarro; Alejandro Muñoz; David Varillas-Delgado; Francisco Amaro-Gahete; Justin Roberts; Juan Del Coso. Placebo Effect of Caffeine on Substrate Oxidation during Exercise. Nutrients 2021, 13, 782 .
AMA StyleJorge Gutiérrez-Hellín, Carlos Ruiz-Moreno, Millán Aguilar-Navarro, Alejandro Muñoz, David Varillas-Delgado, Francisco Amaro-Gahete, Justin Roberts, Juan Del Coso. Placebo Effect of Caffeine on Substrate Oxidation during Exercise. Nutrients. 2021; 13 (3):782.
Chicago/Turabian StyleJorge Gutiérrez-Hellín; Carlos Ruiz-Moreno; Millán Aguilar-Navarro; Alejandro Muñoz; David Varillas-Delgado; Francisco Amaro-Gahete; Justin Roberts; Juan Del Coso. 2021. "Placebo Effect of Caffeine on Substrate Oxidation during Exercise." Nutrients 13, no. 3: 782.
This study investigated the effect of decaffeinated green tea extract (dGTE), with or without antioxidant nutrients, on fat oxidation, body composition and cardio-metabolic health measures in overweight individuals engaged in regular exercise. Twenty-seven participants (20 females, 7 males; body mass: 77.5 ± 10.5 kg; body mass index: 27.4 ± 3.0 kg·m2; peak oxygen uptake (
Justin Roberts; Ashley Willmott; Liam Beasley; Mariette Boal; Rory Davies; Laurence Martin; Havovi Chichger; Lata Gautam; Juan Del Coso. The Impact of Decaffeinated Green Tea Extract on Fat Oxidation, Body Composition and Cardio-Metabolic Health in Overweight, Recreationally Active Individuals. Nutrients 2021, 13, 764 .
AMA StyleJustin Roberts, Ashley Willmott, Liam Beasley, Mariette Boal, Rory Davies, Laurence Martin, Havovi Chichger, Lata Gautam, Juan Del Coso. The Impact of Decaffeinated Green Tea Extract on Fat Oxidation, Body Composition and Cardio-Metabolic Health in Overweight, Recreationally Active Individuals. Nutrients. 2021; 13 (3):764.
Chicago/Turabian StyleJustin Roberts; Ashley Willmott; Liam Beasley; Mariette Boal; Rory Davies; Laurence Martin; Havovi Chichger; Lata Gautam; Juan Del Coso. 2021. "The Impact of Decaffeinated Green Tea Extract on Fat Oxidation, Body Composition and Cardio-Metabolic Health in Overweight, Recreationally Active Individuals." Nutrients 13, no. 3: 764.
Background Prevalence of vitamin D insufficiency/deficiency has been noted in athletic populations, although less is known about recreationally active individuals. Biofortification of natural food sources (e.g. UV radiated mushrooms) may support vitamin D status and is therefore of current scientific and commercial interest. The aim of this study was to assess the impact of a mushroom-derived food ingredient on vitamin D status in recreationally active, healthy volunteers. Methods Twenty-eight participants were randomly assigned to either: 25 μg (1000 IU) encapsulated natural mushroom-derived vitamin D2; matched-dose encapsulated vitamin D3 or placebo (PL) for 12 weeks. Venous blood samples were collected at baseline, week 6 and 12 for analysis of serum 25(OH)D2 and 25(OH)D3 using liquid chromatography mass spectrometry. Habitual dietary intake and activity were monitored across the intervention. Results Vitamin D status (25(OH)DTOTAL) was significantly increased with vitamin D3 supplementation from 46.1 ± 5.3 nmol·L− 1 to 88.0 ± 8.6 nmol·L− 1 (p < 0.0001) across the intervention, coupled with an expected rise in 25(OH)D3 concentrations from 38.8 ± 5.2 nmol·L− 1 to 82.0 ± 7.9 nmol·L− 1 (p < 0.0001). In contrast, D2 supplementation increased 25(OH)D2 by + 347% (7.0 ± 1.1 nmol·L− 1 to 31.4 ± 2.1 nmol·L− 1, p < 0.0001), but resulted in a − 42% reduction in 25(OH)D3 by week 6 (p = 0.001). A net + 14% increase in 25(OH)DTOTAL was established with D2 supplementation by week 12 (p > 0.05), which was not statistically different to D3. Vitamin D status was maintained with PL, following an initial − 15% reduction by week 6 (p ≤ 0.046 compared to both supplement groups). Conclusions The use of a UV radiated mushroom food ingredient was effective in maintaining 25(OH)DTOTAL in healthy, recreationally active volunteers. This may offer an adjunct strategy in supporting vitamin D intake. However, consistent with the literature, the use of vitamin D3 supplementation likely offers benefits when acute elevation in vitamin D status is warranted.
Jorge Marques Pinto; Viviane Merzbach; Ashley G. B. Willmott; Jose Antonio; Justin Roberts. Assessing the impact of a mushroom-derived food ingredient on vitamin D levels in healthy volunteers. Journal of the International Society of Sports Nutrition 2020, 17, 1 -10.
AMA StyleJorge Marques Pinto, Viviane Merzbach, Ashley G. B. Willmott, Jose Antonio, Justin Roberts. Assessing the impact of a mushroom-derived food ingredient on vitamin D levels in healthy volunteers. Journal of the International Society of Sports Nutrition. 2020; 17 (1):1-10.
Chicago/Turabian StyleJorge Marques Pinto; Viviane Merzbach; Ashley G. B. Willmott; Jose Antonio; Justin Roberts. 2020. "Assessing the impact of a mushroom-derived food ingredient on vitamin D levels in healthy volunteers." Journal of the International Society of Sports Nutrition 17, no. 1: 1-10.
Objective Low-grade inflammation in the young may contribute to the early development of adverse cardiometabolic risk profiles. We assessed whether measures of glycoprotein acetylation (GlycA) were better able to detect the development of these changes compared to the more commonly used biomarker high-sensitivity C-reactive protein (CRP), and investigated whether these relationships differed in an adolescent compared to young adult cohort. Research Design and Methods A total of 3306 adolescents (Avon Longitudinal Study of Parents and Children - ALSPAC; mean age 15.4±0.3; n=1750) and young adults (Cardiovascular Risk in Young Finns Study - YFS; mean age 32.1±5.0; n=1556) were included. Inflammatory biomarkers (GlycA/CRP), body composition (BMI / waist circumference) and cardiometabolic risk factors (blood pressure, triglycerides, HDL-c, glucose, insulin, and homeostasis model of insulin resistance [HOMA_IR]), were measured at baseline and again in 9-10 year follow-up. Metabolic Syndrome (MetS) was defined using adolescent-specific National Cholesterol Education Programme (NCEP) guidelines in ALSPAC and standard NCEP guidelines in YFS. Results GlycA levels showed greater within-subject correlation over the 9-10 year duration of follow-up in both cohorts when compared to CRP, particularly in the younger adolescent group. In adjusted models, only GlycA was found to increase in line with cardiometabolic risk factor burden at baseline, and to predict adverse changes in several cardiometabolic risk factors in follow-up. In both cohorts, GlycA predicted future risk of MetS (OR [95%CI] for Q4 vs. Q1 = 1.95 [1.08,3.53] and 2.74 [1.30,5.73] for ALSPAC and YFS, respectively), whereas CRP showed a neutral or even negative relationship in fully-adjusted models (OR [95%CI] = 0.50 [0.29,0.86] and 0.93 [0.53,1.64]). Conclusions Chronic inflammation is associated with adverse cardiometabolic risk profiles from as early as adolescence and predicts risk of future cardiometabolic risk and MetS in up to 10 year follow-up. GlycA may be a more sensitive inflammatory biomarker to CRP for detecting early cardiometabolic and cardiovascular risk in the young.
Scott T. Chiesa; Marietta Charakida; Georgios Georgiopoulos; Justin D. Roberts; Simon J. Stafford; Chloe Park; Juha Mykkänen; Mika Kähönen; Terho Lehtimäki; Mika Ala-Korpela; Olli Raitakari; Alun D. Hughes; Naveed Sattar; Nicholas J. Timpson; John E. Deanfield. Elevated glycoprotein acetyl levels in adolescence and early adulthood predict adverse cardiometabolic profiles and risk of metabolic syndrome in up to 10 year follow-up. 2020, 1 .
AMA StyleScott T. Chiesa, Marietta Charakida, Georgios Georgiopoulos, Justin D. Roberts, Simon J. Stafford, Chloe Park, Juha Mykkänen, Mika Kähönen, Terho Lehtimäki, Mika Ala-Korpela, Olli Raitakari, Alun D. Hughes, Naveed Sattar, Nicholas J. Timpson, John E. Deanfield. Elevated glycoprotein acetyl levels in adolescence and early adulthood predict adverse cardiometabolic profiles and risk of metabolic syndrome in up to 10 year follow-up. . 2020; ():1.
Chicago/Turabian StyleScott T. Chiesa; Marietta Charakida; Georgios Georgiopoulos; Justin D. Roberts; Simon J. Stafford; Chloe Park; Juha Mykkänen; Mika Kähönen; Terho Lehtimäki; Mika Ala-Korpela; Olli Raitakari; Alun D. Hughes; Naveed Sattar; Nicholas J. Timpson; John E. Deanfield. 2020. "Elevated glycoprotein acetyl levels in adolescence and early adulthood predict adverse cardiometabolic profiles and risk of metabolic syndrome in up to 10 year follow-up." , no. : 1.
We assessed dietary intake and nitrogen balance during 14 weeks of Basic Training (BT) in British Army Infantry recruits. Nineteen men (mean ± SD: age 19.9 ± 2.6 years, height: 175.7 ± 6.5 cm, body mass 80.3 ± 10.1 kg) at the Infantry Training Centre, Catterick (ITC(C)) volunteered. Nutrient intakes and 24-h urinary nitrogen balance were assessed in weeks 2, 6 and 11 of BT. Nutrient intake was assessed using researcher-led weighed food records and food diaries, and Nutritics professional dietary software. Data were compared between weeks using a repeated-measures analysis of variance (ANOVA) with statistical significance set at p ≤ 0.05. There was a significant difference in protein intake (g) between weeks 2 and 11 of BT (115 ± 18 vs. 91 ± 20 g, p = 0.02, ES = 1.26). There was no significant difference in mean absolute daily energy (p = 0.44), fat (p = 0.79) or carbohydrate (CHO) intake (p = 0.06) between weeks. Nitrogen balance was maintained in weeks 2, 6 and 11, but declined throughout BT (2: 4.6 ± 4.1 g, 6: 1.6 ± 4.5 g, 11: −0.2 ± 5.5 g, p = 0.07). A protein intake of 1.5 g·kg−1·d−1 may be sufficient in the early stages of BT, but higher intakes may be individually needed later on in BT.
Shaun Chapman; Alex J. Rawcliffe; Rachel Izard; Kimberley Jacka; Hayley Tyson; Lee Smith; Justin Roberts. Dietary Intake and Nitrogen Balance in British Army Infantry Recruits Undergoing Basic Training. Nutrients 2020, 12, 2125 .
AMA StyleShaun Chapman, Alex J. Rawcliffe, Rachel Izard, Kimberley Jacka, Hayley Tyson, Lee Smith, Justin Roberts. Dietary Intake and Nitrogen Balance in British Army Infantry Recruits Undergoing Basic Training. Nutrients. 2020; 12 (7):2125.
Chicago/Turabian StyleShaun Chapman; Alex J. Rawcliffe; Rachel Izard; Kimberley Jacka; Hayley Tyson; Lee Smith; Justin Roberts. 2020. "Dietary Intake and Nitrogen Balance in British Army Infantry Recruits Undergoing Basic Training." Nutrients 12, no. 7: 2125.
Protein is an important component of a healthy diet and appears to be integral to enhancing training adaptations in exercising individuals. The purpose of this narrative review is to provide an evidence-based assessment of the current literature examining increases in dietary protein intake above the recommended dietary allowance (RDA: 0.8 g/kg/d) in conjunction with chronic exercise on body composition (i.e., muscle, fat and bone). We also highlight acute and chronic pre-sleep protein studies as well as the influence of exercise timing on body composition. Overall, a high-protein diet appears to increase muscle accretion and fat loss and may have beneficial effects on bone when combined with exercise. Pre-sleep protein is a viable strategy to help achieve total daily protein goals. Importantly, there appears to be no deleterious effects from a high-protein diet on muscle, fat or bone in exercising individuals.
Jose Antonio; Darren G. Candow; Scott C. Forbes; Michael J. Ormsbee; Patrick G. Saracino; Justin Roberts. Effects of Dietary Protein on Body Composition in Exercising Individuals. Nutrients 2020, 12, 1890 .
AMA StyleJose Antonio, Darren G. Candow, Scott C. Forbes, Michael J. Ormsbee, Patrick G. Saracino, Justin Roberts. Effects of Dietary Protein on Body Composition in Exercising Individuals. Nutrients. 2020; 12 (6):1890.
Chicago/Turabian StyleJose Antonio; Darren G. Candow; Scott C. Forbes; Michael J. Ormsbee; Patrick G. Saracino; Justin Roberts. 2020. "Effects of Dietary Protein on Body Composition in Exercising Individuals." Nutrients 12, no. 6: 1890.
Objective This study aimed to investigate the potential antiobesity benefits of hot tea consumption at the population level. Methods Using data from the National Health and Nutrition Examination Survey (NHANES) 2003‐2006, the association between hot tea consumption and dual‐energy x‐ray–measured body fat was examined in a large representative sample of US adults (n = 5,681, 51.9% women). Results Compared with non–tea drinkers, men who consumed 0.25 to 1 cup per day of hot tea had 1.5% (95% CI: 0.4% to 2.6%) and 1.7% (95% CI: 0.4% to 3.0%) less total and trunk body fat, respectively. The associations were stronger among men 45 to 69 years old compared with younger men (20‐44 years). For men who consumed 1 or more cups per day of hot tea, lower total (−1.2%, 95% CI: −2.3% to −0.2%) and trunk body fat (−1.3%, 95% CI: −2.6 to −0.1%) was observed among men 45 to 69 years old only. In women, those who drank 1 or more cups per day had 1.5% lower (95% CI: −2.7% to −0.3%) trunk body fat compared with non–tea drinkers. Conclusions Consumption of hot tea might be considered as part of a healthy diet in order to support parameters associated with metabolic health and may be particularly important in older male age groups in supporting reduced central adiposity.
Justin Roberts; Qinran Liu; Chao Cao; Sarah E. Jackson; Xiaoyu Zong; Gretchen A. Meyer; Lin Yang; W. Todd Cade; Xiaobin Zheng; Guillermo Felipe López Sánchez; Xiaojian Wu; Lee Smith. Association of Hot Tea Consumption with Regional Adiposity Measured by Dual‐Energy X‐Ray Absorptiometry in NHANES 2003‐2006. Obesity 2020, 28, 445 -451.
AMA StyleJustin Roberts, Qinran Liu, Chao Cao, Sarah E. Jackson, Xiaoyu Zong, Gretchen A. Meyer, Lin Yang, W. Todd Cade, Xiaobin Zheng, Guillermo Felipe López Sánchez, Xiaojian Wu, Lee Smith. Association of Hot Tea Consumption with Regional Adiposity Measured by Dual‐Energy X‐Ray Absorptiometry in NHANES 2003‐2006. Obesity. 2020; 28 (2):445-451.
Chicago/Turabian StyleJustin Roberts; Qinran Liu; Chao Cao; Sarah E. Jackson; Xiaoyu Zong; Gretchen A. Meyer; Lin Yang; W. Todd Cade; Xiaobin Zheng; Guillermo Felipe López Sánchez; Xiaojian Wu; Lee Smith. 2020. "Association of Hot Tea Consumption with Regional Adiposity Measured by Dual‐Energy X‐Ray Absorptiometry in NHANES 2003‐2006." Obesity 28, no. 2: 445-451.
Background British Army Phase One training exposes men and women to challenging distances of 13.5 km·d− 1 vs. 11.8 km·d− 1 and energy expenditures of ~ 4000 kcal·d− 1 and ~ 3000 kcal·d− 1, respectively. As such, it is essential that adequate nutrition is provided to support training demands. However, to date, there is a paucity of data on habitual dietary intake of British Army recruits. The aims of this study were to: (i) compare habitual dietary intake in British Army recruits undergoing Phase One training to Military Dietary Reference Values (MDRVs), and (ii) establish if there was a relative sex difference in dietary intake between men and women. Method Researcher led weighed food records and food diaries were used to assess dietary intake in twenty-eight women (age 21.4 ± 3.0 yrs., height: 163.7 ± 5.0 cm, body mass 65.0 ± 6.7 kg), and seventeen men (age 20.4 ± 2.3 yrs., height: 178.0 ± 7.9 cm, body mass 74.6 ± 8.1 kg) at the Army Training Centre, Pirbright for 8-days in week ten of training. Macro and micronutrient content were estimated using dietary analysis software (Nutritics, Dublin) and assessed via an independent sample t-test to establish if there was a sex difference in daily energy, macro or micronutrient intakes. Results Estimated daily energy intake was less than the MDRV for both men and women, with men consuming a greater amount of energy compared with women (2846 ± 573 vs. 2207 ± 585 kcal·day− 1, p < 0.001). Both sexes under consumed carbohydrate (CHO) when data was expressed relative to body mass with men consuming a greater amount than women (4.8 ± 1.3 vs. 3.8 ± 1.4 g·kg− 1·day− 1, p = 0.025, ES = 0.74). Both sexes also failed to meet MDRVs for protein intake with men consuming more than women (1.5 ± 0.3 vs. 1.3 ± 0.3 g·kg− 1·day− 1, p > 0.030, ES = 0.67). There were no differences in dietary fat intake between men and women (1.5 ± 0.2 vs. 1.5 ± 0.5 g·kg− 1·day− 1, p = 0.483, ES = 0.00). Conclusions Daily EI in men and women in Phase One training does not meet MDRVs. Interventions to increase macronutrient intakes should be considered along with research investigating the potential benefits for increasing different macronutrient intakes on training adaptations.
Shaun Chapman; Justin Roberts; Lee Smith; Alex Rawcliffe; Rachel Izard. Sex differences in dietary intake in British Army recruits undergoing phase one training. Journal of the International Society of Sports Nutrition 2019, 16, 1 -9.
AMA StyleShaun Chapman, Justin Roberts, Lee Smith, Alex Rawcliffe, Rachel Izard. Sex differences in dietary intake in British Army recruits undergoing phase one training. Journal of the International Society of Sports Nutrition. 2019; 16 (1):1-9.
Chicago/Turabian StyleShaun Chapman; Justin Roberts; Lee Smith; Alex Rawcliffe; Rachel Izard. 2019. "Sex differences in dietary intake in British Army recruits undergoing phase one training." Journal of the International Society of Sports Nutrition 16, no. 1: 1-9.
Background In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~ 60% of energy intake, 5–8 g·kg− 1·d− 1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~ 1.6 g·kg− 1·d− 1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 g.kg− 1·d− 1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150–400 Kcal·h− 1 (carbohydrate, 30–50 g·h− 1; protein, 5–10 g·h− 1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450–750 mL·h− 1 (~ 150–250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., > 575 mg·L− 1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety.
Nicholas Tiller; Justin D. Roberts; Liam Beasley; Shaun Chapman; Jorge M. Pinto; Lee Smith; Melanie Wiffin; Mark Russell; Andy Sparks; Lauren Duckworth; John O’Hara; Louise Sutton; Jose Antonio; Darryn S. Willoughby; Michael D. Tarpey; Abbie E. Smith-Ryan; Michael J. Ormsbee; Todd A. Astorino; Richard Kreider; Graham McGinnis; Jeffrey R. Stout; Johneric W. Smith; Shawn M. Arent; Bill I. Campbell; Laurent Bannock. International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition 2019, 16, 1 -23.
AMA StyleNicholas Tiller, Justin D. Roberts, Liam Beasley, Shaun Chapman, Jorge M. Pinto, Lee Smith, Melanie Wiffin, Mark Russell, Andy Sparks, Lauren Duckworth, John O’Hara, Louise Sutton, Jose Antonio, Darryn S. Willoughby, Michael D. Tarpey, Abbie E. Smith-Ryan, Michael J. Ormsbee, Todd A. Astorino, Richard Kreider, Graham McGinnis, Jeffrey R. Stout, Johneric W. Smith, Shawn M. Arent, Bill I. Campbell, Laurent Bannock. International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition. 2019; 16 (1):1-23.
Chicago/Turabian StyleNicholas Tiller; Justin D. Roberts; Liam Beasley; Shaun Chapman; Jorge M. Pinto; Lee Smith; Melanie Wiffin; Mark Russell; Andy Sparks; Lauren Duckworth; John O’Hara; Louise Sutton; Jose Antonio; Darryn S. Willoughby; Michael D. Tarpey; Abbie E. Smith-Ryan; Michael J. Ormsbee; Todd A. Astorino; Richard Kreider; Graham McGinnis; Jeffrey R. Stout; Johneric W. Smith; Shawn M. Arent; Bill I. Campbell; Laurent Bannock. 2019. "International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing." Journal of the International Society of Sports Nutrition 16, no. 1: 1-23.
Variations in the fat mass and obesity-associated gene (FTO) are associated with obesity; however, it is unclear if changes in energy intake affect the adaptive response to caloric restriction in those with risk variants. The three FTO single nucleotide polymorphisms (SNPs), rs1421085, rs17817449 and rs9939609, are in strong linkage disequilibrium. Thus, the purpose of this investigation was to determine the role of these FTO SNPs vis-à-vis the effects of a 4-week hypocaloric diet on body composition in exercise-trained men and women. Two salivary biomarkers that associate with energy expenditure were also assessed (cortisol and salivary alpha-amylase, sAA). Forty-seven exercise-trained men (n = 11) and women (n = 36) (mean ± SD: age 32 ± 9 years; height 169 ± 8 cm, body mass index 24.5 ± 2.9 kg/m2, hours of aerobic training per week 4.9 ± 3.8, hours of weight training per week 3.9 ± 2.4, years of training experience 13.4 ± 7.0) completed a 4-week hypocaloric diet (i.e., decrease total calories by ~ 20–25% while maintaining a protein intake of ~ 2.0 g/kg/d). Subjects were instructed to maintain the same training regimen and to decrease energy intake via carbohydrate and/or fat restriction during the treatment period. Body composition was assessed via dual-energy X-ray absorptiometry (DXA) (Model: Hologic Horizon W; Hologic Inc., Danbury CT USA). Total body water was determined via a multifrequency bioelectrical impedance (BIA) device (InBody 770). Saliva samples were collected pre and post intervention in order to genotype the participants as well as to determine the concentrations of cortisol and sAA. Of the 47 subjects, 15 were of normal risk for obesity whereas 32 were carriers of the FTO gene risk alleles. Subjects were grouped based on their genotype for the three FTO SNPs (i.e., rs1421085, rs17817449 and rs9939609) due to their strong linkage disequilibrium. We have classified those with the normal obesity risk as “non-risk allele” versus those that carry the “risk allele” (i.e., both heterozygous and homozygous). Both groups experienced a significant decrease in total energy intake (p < 0.01); non-risk allele: pre kcal 2081 ± 618, post kcal 1703 ± 495; risk allele: pre kcal 1886 ± 515, post kcal 1502 ± 366). Both groups lost a significant amount of body weight (p < 0.01); however, there was no difference between groups for the change (post minus pre) in each group (risk allele change: − 1.0 ± 1.2 kg, non-risk allele change: − 1.2 ± 1.4 kg). Additionally, both groups lost a significant amount of fat mass (p < 0.01) with no differences between groups for the change in fat mass (risk allele change for fat mass: 1.1 ± 0.7 kg, non-risk allele change − 0.9 ± 0.4 kg). There were no significant changes in either group for fat free mass or total body water. The change in salivary alpha-amylase or cortisol was not different between groups. In the short-term (i.e., 4 weeks), exercise-trained men and women consuming a hypocaloric diet that is relatively high in protein experience similar changes in body composition due exclusively to a decrement in fat mass and independent of FTO allele status. Therefore, weight and fat loss on a hypocaloric diet is, at least in the short-term, unaffected by the FTO gene.
Jose Antonio; Sarah Knafo; Madaline Kenyon; Alina Ali; Cassandra Carson; Anya Ellerbroek; Cailey Weaver; Justin Roberts; Corey A. Peacock; Jaime L. Tartar. Assessment of the FTO gene polymorphisms (rs1421085, rs17817449 and rs9939609) in exercise-trained men and women: the effects of a 4-week hypocaloric diet. Journal of the International Society of Sports Nutrition 2019, 16, 1 -9.
AMA StyleJose Antonio, Sarah Knafo, Madaline Kenyon, Alina Ali, Cassandra Carson, Anya Ellerbroek, Cailey Weaver, Justin Roberts, Corey A. Peacock, Jaime L. Tartar. Assessment of the FTO gene polymorphisms (rs1421085, rs17817449 and rs9939609) in exercise-trained men and women: the effects of a 4-week hypocaloric diet. Journal of the International Society of Sports Nutrition. 2019; 16 (1):1-9.
Chicago/Turabian StyleJose Antonio; Sarah Knafo; Madaline Kenyon; Alina Ali; Cassandra Carson; Anya Ellerbroek; Cailey Weaver; Justin Roberts; Corey A. Peacock; Jaime L. Tartar. 2019. "Assessment of the FTO gene polymorphisms (rs1421085, rs17817449 and rs9939609) in exercise-trained men and women: the effects of a 4-week hypocaloric diet." Journal of the International Society of Sports Nutrition 16, no. 1: 1-9.
The psychomotor vigilance test (PVT) measures one’s behavioral alertness. It is a visual test that involves measuring the speed at which a person reacts to visual stimuli over a fixed time frame (e.g., 5 min). The purpose of this study was to assess the effects of an energy drink on psychomotor vigilance as well as a simple measure of muscular endurance (i.e., push-ups). A total of 20 exercise-trained men (n = 11) and women (n = 9) (mean SD: age 32 7 years; height 169 10 cm; weight; 74.5 14.5 kg; percent body fat 20.3 6.2%; years of training 14 9; daily caffeine intake 463 510 mg) volunteered for this randomized, double-blind, placebo-controlled, crossover trial. In a randomized counterbalanced order, they consumed either the energy drink (ED) (product: BANG®, Weston Florida) or a similar tasting placebo drink (PL). In the second visit after a 1-week washout period, they consumed the alternate drink. A full 30 minutes post-consumption, they performed the following tests in this order: a 5-minute psychomotor vigilance test, three sets of push-ups, followed once more by a 5-minute psychomotor vigilance test. Reaction time was recorded. For the psychomotor vigilance test, lapses, false starts and efficiency score are also assessed. There were no differences between groups for the number of push-ups that were performed or the number of false starts during the psychomotor vigilance test. However, the ED treatment resulted in a significantly lower (i.e., faster) psychomotor vigilance mean reaction time compared to the PL (p = 0.0220) (ED 473.8 42.0 milliseconds, PL 482.4 54.0 milliseconds). There was a trend for the ED to lower the number of lapses (i.e., reaction time > 500 milliseconds) (p = 0.0608). The acute consumption of a commercially available ED produced a significant improvement in psychomotor vigilance in exercise-trained men and women.
Jose Antonio; Madaline Kenyon; Christopher Horn; Lia Jiannine; Cassandra Carson; Anya Ellerbroek; Justin Roberts; Corey Peacock; Jaime Tartar. The Effects of an Energy Drink on Psychomotor Vigilance in Trained Individuals. Journal of Functional Morphology and Kinesiology 2019, 4, 47 .
AMA StyleJose Antonio, Madaline Kenyon, Christopher Horn, Lia Jiannine, Cassandra Carson, Anya Ellerbroek, Justin Roberts, Corey Peacock, Jaime Tartar. The Effects of an Energy Drink on Psychomotor Vigilance in Trained Individuals. Journal of Functional Morphology and Kinesiology. 2019; 4 (3):47.
Chicago/Turabian StyleJose Antonio; Madaline Kenyon; Christopher Horn; Lia Jiannine; Cassandra Carson; Anya Ellerbroek; Justin Roberts; Corey Peacock; Jaime Tartar. 2019. "The Effects of an Energy Drink on Psychomotor Vigilance in Trained Individuals." Journal of Functional Morphology and Kinesiology 4, no. 3: 47.
The authors wish to make a correction to the published version of their paper [...].
Justin Roberts; Anastasia Zinchenko; KrishnaA Mahbubani; James Johnstone; Lee Smith; Viviane Merzbach; Miguel Blacutt; Oscar Banderas; Luis Villasenor; Fredrik T. Vårvik; Menno Henselmans. Correction: Roberts et al. "Satiating Effect of High Protein Diets on Resistance-Trained Individuals in Energy Deficit" Nutrients 2019, 11(1), 56. Nutrients 2019, 11, 1543 .
AMA StyleJustin Roberts, Anastasia Zinchenko, KrishnaA Mahbubani, James Johnstone, Lee Smith, Viviane Merzbach, Miguel Blacutt, Oscar Banderas, Luis Villasenor, Fredrik T. Vårvik, Menno Henselmans. Correction: Roberts et al. "Satiating Effect of High Protein Diets on Resistance-Trained Individuals in Energy Deficit" Nutrients 2019, 11(1), 56. Nutrients. 2019; 11 (7):1543.
Chicago/Turabian StyleJustin Roberts; Anastasia Zinchenko; KrishnaA Mahbubani; James Johnstone; Lee Smith; Viviane Merzbach; Miguel Blacutt; Oscar Banderas; Luis Villasenor; Fredrik T. Vårvik; Menno Henselmans. 2019. "Correction: Roberts et al. "Satiating Effect of High Protein Diets on Resistance-Trained Individuals in Energy Deficit" Nutrients 2019, 11(1), 56." Nutrients 11, no. 7: 1543.
Justin Roberts; Anastasia Zinchenko; KrishnaA Mahbubani; James Johnstone; Lee Smith; Vivianne Merzbach; Miguel Blacutt; Oscar Banderas; Luis Villasenor; Fredrik Varvik; Menno Henselmans. Satiating Effect Of High Protein Diets On Resistance-trained Individuals In Energy Deficit. Medicine & Science in Sports & Exercise 2019, 51, 543 -544.
AMA StyleJustin Roberts, Anastasia Zinchenko, KrishnaA Mahbubani, James Johnstone, Lee Smith, Vivianne Merzbach, Miguel Blacutt, Oscar Banderas, Luis Villasenor, Fredrik Varvik, Menno Henselmans. Satiating Effect Of High Protein Diets On Resistance-trained Individuals In Energy Deficit. Medicine & Science in Sports & Exercise. 2019; 51 (6S):543-544.
Chicago/Turabian StyleJustin Roberts; Anastasia Zinchenko; KrishnaA Mahbubani; James Johnstone; Lee Smith; Vivianne Merzbach; Miguel Blacutt; Oscar Banderas; Luis Villasenor; Fredrik Varvik; Menno Henselmans. 2019. "Satiating Effect Of High Protein Diets On Resistance-trained Individuals In Energy Deficit." Medicine & Science in Sports & Exercise 51, no. 6S: 543-544.
The purpose of this investigation was to compare two different methods of assessing body composition (i.e., a multi-frequency bioelectrical impedance analysis (MF-BIA) and dual-energy x-ray absorptiometry (DXA)) over a four-week treatment period in exercise-trained men and women. Subjects were instructed to reduce their energy intake while maintaining the same exercise regimen for a period of four weeks. Pre and post assessments for body composition (i.e., fat-free mass, fat mass, percent body fat) were determined via the MF-BIA and DXA. On average, subjects reduced their energy intake by ~18 percent. The MF-BIA underestimated fat mass and percentage body fat and overestimated fat-free mass in comparison to the DXA. However, when assessing the change in fat mass, fat-free mass or percent body fat, there were no statistically significant differences between the MF-BIA vs. DXA. Overall, the change in percent body fat using the DXA vs. the MF-BIA was −1.3 ± 0.9 and −1.4 ± 1.8, respectively. Our data suggest that when tracking body composition over a period of four weeks, the MF-BIA may be a viable alternative to the DXA in exercise-trained men and women.
Jose Antonio; Madaline Kenyon; Anya Ellerbroek; Cassandra Carson; Victoria Burgess; Denvyr Tyler-Palmer; Jonathan Mike; Justin Roberts; Gerseli Angeli; Corey Peacock. Comparison of Dual-Energy X-Ray Absorptiometry (DXA) versus a Multi-frequency Bioelectrical Impedance (InBody 770) Device for Body Composition Assessment after a 4-Week Hypoenergetic Diet. Journal of Functional Morphology and Kinesiology 2019, 4, 23 .
AMA StyleJose Antonio, Madaline Kenyon, Anya Ellerbroek, Cassandra Carson, Victoria Burgess, Denvyr Tyler-Palmer, Jonathan Mike, Justin Roberts, Gerseli Angeli, Corey Peacock. Comparison of Dual-Energy X-Ray Absorptiometry (DXA) versus a Multi-frequency Bioelectrical Impedance (InBody 770) Device for Body Composition Assessment after a 4-Week Hypoenergetic Diet. Journal of Functional Morphology and Kinesiology. 2019; 4 (2):23.
Chicago/Turabian StyleJose Antonio; Madaline Kenyon; Anya Ellerbroek; Cassandra Carson; Victoria Burgess; Denvyr Tyler-Palmer; Jonathan Mike; Justin Roberts; Gerseli Angeli; Corey Peacock. 2019. "Comparison of Dual-Energy X-Ray Absorptiometry (DXA) versus a Multi-frequency Bioelectrical Impedance (InBody 770) Device for Body Composition Assessment after a 4-Week Hypoenergetic Diet." Journal of Functional Morphology and Kinesiology 4, no. 2: 23.
Research has demonstrated that low fermentable oligiosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diets improve gastrointestinal (GI) symptoms in irritable bowel syndrome sufferers. Exercise-related GI issues are a common cause of underperformance, with current evidence focusing on the use of FODMAP approaches with recreationally competitive or highly trained athletes. However, there is a paucity of research exploring the potential benefit of FODMAP strategies to support healthy, recreational athletes who experience GI issues during training. This study therefore aimed to assess whether a short-term LOWFODMAP diet improved exercise-related GI symptoms and the perceived ability to exercise in recreational runners. Sixteen healthy volunteers were randomly assigned in a crossover design manner to either a LOWFODMAP (16.06 ± 1.79 g·d- 1) or HIGHFODMAP (38.65 ± 6.66 g·d- 1) diet for 7 days, with a one week washout period followed by a further 7 days on the alternate diet. Participants rated their gastrointestinal symptoms on an adapted version of the Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) questionnaire before and at the end of each dietary period. Perceived ability to exercise (frequency, intensity and duration) in relation to each dietary period was also rated using a visual analogue scale. Resting blood samples were collected prior to and on completion of each diet to determine plasma intestinal fatty acid binding protein (I-FABP) as a marker of acute GI injury. Overall IBS-SSS score significantly reduced in the LOWFODMAP condition from 81.1 ± 16.4 to 31.3 ± 9.2 (arbitrary units; P = 0.004). Perceived exercise frequency (z = 2.309, P = 0.02) and intensity (z = 2.687, P = 0.007) was significantly improved following a short-term LOWFODMAP approach compared to HIGHFODMAP. No significant differences were reported between dietary conditions for plasma I-FABP (P > 0.05). A short-term LOWFODMAP diet under free-living conditions reduced exercise-related GI symptoms and improved the perceived ability to exercise in otherwise healthy, recreational runners. These findings may be explained by a reduction in indigestible carbohydrates available for fermentation in the gut. The therapeutic benefits of LOWFODMAP diets in recreational and trained athletes during sustained training periods warrants further investigation.
Melanie Wiffin; Lee Smith; Jose Antonio; James Johnstone; Liam Beasley; Justin Roberts. Effect of a short-term low fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diet on exercise-related gastrointestinal symptoms. Journal of the International Society of Sports Nutrition 2019, 16, 1 .
AMA StyleMelanie Wiffin, Lee Smith, Jose Antonio, James Johnstone, Liam Beasley, Justin Roberts. Effect of a short-term low fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diet on exercise-related gastrointestinal symptoms. Journal of the International Society of Sports Nutrition. 2019; 16 (1):1.
Chicago/Turabian StyleMelanie Wiffin; Lee Smith; Jose Antonio; James Johnstone; Liam Beasley; Justin Roberts. 2019. "Effect of a short-term low fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diet on exercise-related gastrointestinal symptoms." Journal of the International Society of Sports Nutrition 16, no. 1: 1.
Short-term energy deficit strategies are practiced by weight class and physique athletes, often involving high protein intakes to maximize satiety and maintain lean mass despite a paucity of research. This study compared the satiating effect of two protein diets on resistance-trained individuals during short-term energy deficit. Following ethical approval, 16 participants (age: 28 ± 2 years; height: 1.72 ± 0.03 m; body-mass: 88.83 ± 5.54 kg; body-fat: 21.85 ± 1.82%) were randomly assigned to 7-days moderate (PROMOD: 1.8 g·kg−1·d−1) or high protein (PROHIGH: 2.9 g·kg−1·d−1) matched calorie-deficit diets in a cross-over design. Daily satiety responses were recorded throughout interventions. Pre-post diet, plasma ghrelin and peptide tyrosine tyrosine (PYY), and satiety ratings were assessed in response to a protein-rich meal. Only perceived satisfaction was significantly greater following PROHIGH (67.29 ± 4.28 v 58.96 ± 4.51 mm, p = 0.04). Perceived cravings increased following PROMOD only (46.25 ± 4.96 to 57.60 ± 4.41 mm, p = 0.01). Absolute ghrelin concentration significantly reduced post-meal following PROMOD (972.8 ± 130.4 to 613.6 ± 114.3 pg·mL−1; p = 0.003), remaining lower than PROHIGH at 2 h (−0.40 ± 0.06 v −0.26 ± 0.06 pg·mL−1 normalized relative change; p = 0.015). Absolute PYY concentration increased to a similar extent post-meal (PROMOD: 84.9 ± 8.9 to 147.1 ± 11.9 pg·mL−1, PROHIGH: 100.6 ± 9.5 to 143.3 ± 12.0 pg·mL−1; p < 0.001), but expressed as relative change difference was significantly greater for PROMOD at 2 h (+0.39 ± 0.20 pg·mL−1 v −0.28 ± 0.12 pg·mL−1; p = 0.001). Perceived hunger, fullness and satisfaction post-meal were comparable between diets (p > 0.05). However, desire to eat remained significantly blunted for PROMOD (p = 0.048). PROHIGH does not confer additional satiating benefits in resistance-trained individuals during short-term energy deficit. Ghrelin and PYY responses to a test-meal support the contention that satiety was maintained following PROMOD, although athletes experiencing negative symptoms (i.e., cravings) may benefit from protein-rich meals as opposed to over-consumption of protein.
Justin Roberts; Anastasia Zinchenko; Krishnaa T. Mahbubani; James Johnstone; Lee Smith; Viviane Merzbach; Miguel Blacutt; Oscar Banderas; Luis Villasenor; Fredrik T. Vårvik; Menno Henselmans. Satiating Effect of High Protein Diets on Resistance-Trained Individuals in Energy Deficit. Nutrients 2018, 11, 56 .
AMA StyleJustin Roberts, Anastasia Zinchenko, Krishnaa T. Mahbubani, James Johnstone, Lee Smith, Viviane Merzbach, Miguel Blacutt, Oscar Banderas, Luis Villasenor, Fredrik T. Vårvik, Menno Henselmans. Satiating Effect of High Protein Diets on Resistance-Trained Individuals in Energy Deficit. Nutrients. 2018; 11 (1):56.
Chicago/Turabian StyleJustin Roberts; Anastasia Zinchenko; Krishnaa T. Mahbubani; James Johnstone; Lee Smith; Viviane Merzbach; Miguel Blacutt; Oscar Banderas; Luis Villasenor; Fredrik T. Vårvik; Menno Henselmans. 2018. "Satiating Effect of High Protein Diets on Resistance-Trained Individuals in Energy Deficit." Nutrients 11, no. 1: 56.
β-alanine (βA) supplementation has been shown to increase intramuscular carnosine content and subsequent high-intensity performance in events lasting < 4 minutes (min), which may be dependent on total, as opposed to daily, dose. The ergogenic effect of βA has also been demonstrated for 2000-m rowing performance prompting interest in whether βA may be beneficial for sustained aerobic exercise. This study therefore investigated the effect of two βA dosing strategies on 30-min rowing and subsequent sprint performance. Following University Ethics approval, twenty-seven healthy, male rowers (age: 24 ± 2 years; body-height: 1.81 ± 0.02 m; body-mass: 82.3 ± 2.5 kg; body-fat: 14.2 ± 1.0%) were randomised in a double-blind manner to 4 weeks of: i) βA (2.4 g·d− 1, βA1); ii) matched total βA (4.8 g on alternate days, βA2); or iii) cornflour placebo (2.4 g·d− 1, PL). Participants completed a laboratory 30-min rowing time-trial, followed by 3x30-seconds (s) maximal sprint efforts at days 0, 14 and 28 (T1-T3). Total distance (m), average power (W), relative average power (W·kg− 1), cardio-respiratory measures and perceived exertion were assessed for each 10-min split. Blood lactate ([La-]b mmol·L− 1) was monitored pre-post time-trial and following maximal sprint efforts. A 3-way repeated measures ANOVA was employed for main analyses, with Bonferonni post-hoc assessment (P ≤ 0.05). Total 30-min time-trial distance significantly increased from T1-T3 within βA1 only (7397 ± 195 m to 7580 ± 171 m, P = 0.002, ƞp2 = 0.196), including absolute average power (194.8 ± 18.3 W to 204.2 ± 15.5 W, P = 0.04, ƞp2 = 0.115) and relative average power output (2.28 ± 0.15 W·kg− 1 to 2.41 ± 0.12 W·kg− 1, P = 0.031, ƞp2 = 0.122). These findings were potentially explained by within-group significance for the same variables for the first 10 min split (P ≤ 0.01), and for distance covered (P = 0.01) in the second 10-min split. However, no condition x time interactions were observed. No significant effects were found for sprint variables (P > 0.05) with comparable values at T3 for mean distance (βA1: 163.9 ± 3.8 m; βA2: 161.2 ± 3.5 m; PL: 162.7 ± 3.6 m), average power (βA1: 352.7 ± 14.5 W; βA2: 342.2 ± 13.5 W; PL: 348.2 ± 13.9 W) and lactate (βA1: 10.0 ± 0.9 mmol·L− 1; βA2: 9.2 ± 1.1 mmol·L− 1; PL: 8.7 ± 0.9 mmol·L− 1). Whilst daily βA may confer individual benefits, these results demonstrate limited impact of βA (irrespective of dosing strategy) on 30-min rowing or subsequent sprint performance. Further investigation of βA dosage > 2.4 g·d− 1 and/or chronic intervention periods (> 4–8 weeks) may be warranted based on within-group observations.
Liam Beasley; Lee Smith; Jose Antonio; Dan Gordon; James Johnstone; Justin Roberts. The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized, controlled trial. Journal of the International Society of Sports Nutrition 2018, 15, 1 -11.
AMA StyleLiam Beasley, Lee Smith, Jose Antonio, Dan Gordon, James Johnstone, Justin Roberts. The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized, controlled trial. Journal of the International Society of Sports Nutrition. 2018; 15 (1):1-11.
Chicago/Turabian StyleLiam Beasley; Lee Smith; Jose Antonio; Dan Gordon; James Johnstone; Justin Roberts. 2018. "The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized, controlled trial." Journal of the International Society of Sports Nutrition 15, no. 1: 1-11.
This article discusses the literature on overweight and obesity with a specific focus on older adults. Overweight and obesity refers to an excess of body fat relative to lean body mass. Globally data suggests that overweight and obesity are on the rise and this is likely driving the corresponding increase in metabolic syndrome. Strong evidence exists from meta-analyses that overweight and obesity is associated with increased risk of several physical and mental health conditions, but in older adults some evidence now exists that it may offer protection against some of these conditions, including mortality, particularly in clinical samples. A growing concern in older adults is that of sarcopenic obesity, highlighting a need to reduce both muscle loss and weight gain. Weight loss and conditioning advice may be best delivered to older adults by health care professionals.
Lee Smith; Justin Roberts; James Johnstone; Lin Yang. Overweight and Obesity. Reference Module in Biomedical Sciences 2018, 1 .
AMA StyleLee Smith, Justin Roberts, James Johnstone, Lin Yang. Overweight and Obesity. Reference Module in Biomedical Sciences. 2018; ():1.
Chicago/Turabian StyleLee Smith; Justin Roberts; James Johnstone; Lin Yang. 2018. "Overweight and Obesity." Reference Module in Biomedical Sciences , no. : 1.