Appetite, energy intake and resting metabolic responses to 60 min treadmill running performed in a fasted versus a postprandial state.

This study investigated the effect of fasted and postprandial exercise on appetite, energy intake and resting metabolic responses. Twelve healthy males (mean±SD: age 23±3 years, body mass index 22.9±2.1 kg m(-2), maximum oxygen uptake 57.5±9.7 mL kg(-1) min(-1)) performed three 10 h experimental trials (control, fasted exercise and postprandial exercise) in a Latin Square design. Trials commenced at 8 am after an overnight fast. Sixty min of treadmill running at ∼70% of maximum oxygen uptake was performed at 0-1 h in the fasted exercise trial and 4-5 h in the postprandial exercise trial. A standardised breakfast was provided at 1.5 h and ad libitum buffet meals at 5.5 and 9.5 h. Appetite ratings and resting expired air samples were collected throughout each trial. Postprandial exercise suppressed appetite to a greater extent than fasted exercise. Ad libitum energy intake was not different between trials, resulting in a negative energy balance in exercise trials relative to control after accounting for differences in energy expenditure (control: 9774±2694 kJ; fasted exercise: 6481±2318 kJ; postprandial exercise: 6017±3050 kJ). These findings suggest that 60 min treadmill running induces a negative daily energy balance relative to a sedentary day but is no more effective when performed before or after breakfast

Non-targeted metabolomics in sport and exercise science

Metabolomics incorporates the study of metabolites that are produced and released through physiological processes at both the systemic and cellular level. Biological compounds at the metabolite level are of paramount interest in the sport and exercise sciences, although research in this field has rarely been referred to with the global ‘omics terminology. Commonly studied metabolites in exercise science are notably within cellular pathways for ATP production such as glycolysis (e.g. pyruvate and lactate), β-oxidation of free fatty acids (e.g. palmitate) and ketone bodies (e.g. β-hydroxybutyrate). Non-targeted metabolomic technologies are able to simultaneously analyse the large numbers of metabolites present in human biological samples such as plasma, urine and saliva. These analytical technologies predominately employ nuclear magnetic resonance spectroscopy and chromatography coupled to mass spectrometry. Performing experiments based on non-targeted methods allows for systemic metabolite changes to be analysed and compared to a particular physiological state (e.g. pre/post-exercise) and provides an opportunity to prospect for metabolite signatures that offer beneficial information for translation into an exercise science context, for both elite performance and public health monitoring. This narrative review provides an introduction to non-targeted metabolomic technologies and discusses current and potential applications in sport and exercise science

Listeners are sensitive to the speech breathing time series: Evidence from a gap detection task

The effect of non-speech sounds, such as breathing noise, on the perception of speech timing is currently unclear. In this paper we report the results of three studies investigating participants' ability to detect a silent gap located adjacent to breath sounds during naturalistic speech. Experiment 1 (n = 24, in-person) asked whether participants could either detect or locate a silent gap that was added adjacent to breath sounds during speech. In Experiment 2 (n = 182; online), we investigated whether different placements within an utterance were more likely to elicit successful detection of gaps. In Experiment 3 (n = 102; online), we manipulated the breath sounds themselves to examine the effect of breath-specific characteristics on gap identification. Across the study, we document consistent effects of gap duration, as well as gap placement. Moreover, in Experiment 2, whether a gap was positioned before or after an interjected breath significantly predicted accuracy as well as the duration threshold at which gaps were detected, suggesting that nonverbal aspects of audible speech production specifically shape listeners' temporal expectations. We also describe the influences of the breath sounds themselves, as well as the surrounding speech context, that can disrupt objective gap detection performance. We conclude by contextualising our findings within the literature, arguing that the verbal acoustic signal is not "speech itself" per se, but rather one part of an integrated percept that includes speech-related respiration, which could be more fully explored in speech perception studies

Changes In Jump Performance And Dynamic Balance At High Terrestrial Altitude

The purpose of this study was to examine the effects of altitude on dynamic balance and jump performance of a controlled landing during a 12-day high altitude trek. Following a two-legged jump, time to stabilization (5% of body mass for 0.5 s), maximum power, and jump height were measured in 11 participants using a portable force platform at sea level (BL), 3619 m (C1), and 5140 m (C3). Jump performance significantly decreased at C1 and C3 compared to BL (P=0.001). There were no significant differences found in time to stabilization and maximum power with increasing altitude. The present findings indicate that jump performance is significantly decreased with increasing altitude. However, dynamic balance and jump power remain unaffected

THE IMPACT OF ESSENTIAL AMINO ACID SUPPLEMENTS ENRICHED WITH L-LEUCINE ON APPETITE AND ENERGY INTAKE IN ELDERLY WOMEN

Rationale: Inadequate protein intake (PI), the main source of essential amino acids (EAAs), and reduced appetite are contributing factors to age-related sarcopenia. The satiating effects of dietary protein may negatively affect energy intake (EI), thus there is a need to explore alternative strategies to facilitate PI without compromising appetite and subsequent EI. Methods: Elderly women completed two experiments (EXP1&2) where they consumed either a Bar (B, 135 kcal) or a Gel (G, 114 kcal), rich in EAAs (7.5 g, 40% L-Leucine), or nothing [control (C)]. In EXP1, subjects (n=10, 68±5 years, mean±SD) consumed B, G or C with appetite sensations and appetite-related hormonal responses monitored for 1h, followed by consumption of an ad libitum breakfast (ALB). In EXP2, subjects (n=11, 69±5 years) ingested B, G or C alongside an ALB. Results: In EXP1, EI at ALB was not different (P=0.674) between conditions (282±135, 299±122, 288±131 kcal for C, B and G respectively). However, total EI was significantly higher in B and G compared to C after accounting for the energy content of the supplements (P<0.0005). Analysis revealed significantly higher appetite Area under the Curve (AUC) (P<0.007), a tendency for higher acylated ghrelin AUC (P=0.087), and significantly lower pancreatic polypeptide AUC (P=0.02) in C compared with B and G. In EXP2, EI at ALB was significantly higher (P=0.028) in C (306±122 kcal) compared to B (245±135 kcal) and G (254±118 kcal). However, total EI was significantly higher in B and G after accounting for the energy content of the supplements (P<0.007). Conclusion: Supplementation with either the bar or gel increased total energy intake whether consumed 1h before or during breakfast. This may represent an effective nutritional means for addressing protein and total energy deficiencies in elderly women

Associations between the rate, amount and composition of weight loss as predictors of spontaneous weight regain in adults achieving clinically significant weight loss: a systematic review and meta-regression

Weight regain following weight loss is common although little is known regarding the associations between amount, rate, and composition of weight loss and weight regain. Forty-three studies (52 groups; n = 2379) with longitudinal body composition measurements were identified in which weight loss (≥5%) and subsequent weight regain (≥2%) occurred. Data were synthesized for changes in weight and body composition. Meta-regression models were used to investigate associations between amount, rate, and composition of weight loss and weight regain. Individuals lost 10.9% of their body weight over 13 weeks composed of 19.6% fat-free mass, followed by a regain of 5.4% body weight over 44 weeks composed of 21.6% fat-free mass. Associations between the amount (P < 0.001) and rate (P = 0.049) of weight loss and their interaction (P = 0.042) with weight regain were observed. Fat-free mass (P = 0.017) and fat mass (P < 0.001) loss both predicted weight regain although the effect of fat-free mass was attenuated following adjustment. The amount (P < 0.001), but not the rate of weight loss (P = 0.150), was associated with fat-free mass loss. The amount and rate of weight loss were significant and interacting factors associated with weight regain. Loss of fat-free mass and fat mass explained greater variance in weight regain than weight loss alone

Ballistic Performance Model of Crater Formation in Monolithic, Porous Thermal Protection Systems

Porous monolithic ablative systems insulate atmospheric reentry vehicles from reentry plasmas generated by atmospheric braking from orbital and exo-orbital velocities. Due to the necessity that these materials create a temperature gradient up to several thousand Kelvin over their thickness, it is important that these materials are near their pristine state prior to reentry. These materials may also be on exposed surfaces to space environment threats like orbital debris and meteoroids leaving a probability that these exposed surfaces will be below their prescribed values. Owing to the typical small size of impact craters in these materials, the local flow fields over these craters and the ablative process afford some margin in thermal protection designs for these locally reduced performance values. In this work, tests to develop ballistic performance models for thermal protection materials typical of those being used on Orion are discussed. A density profile as a function of depth of a typical monolithic ablator and substructure system is shown in Figure 1a

Case Study: Using Contemporary Behaviour Change Science to Design and Implement an Effective Nutritional Intervention within Professional Rugby League

Designing and implementing successful dietary intervention is integral to the role of sport nutrition professionals as they attempt to positively change the dietary behaviours of athletes. High-performance sport is a time-pressured environment where immediate results can often supersede pursuit of the most effective evidence-based practice. However, efficacious dietary intervention necessitates comprehensive, systematic and theoretical behavioural design and implementation if the habitual dietary behaviours of athletes are to be positively changed. Therefore, this case study demonstrates how the Behaviour Change Wheel was used to design and implement an effective nutritional intervention within professional rugby league. The eight-step intervention targeted athlete consumption of a high quality dietary intake of 25.1 MJ each day, to achieve an overall body mass increase of 5 kg across a twelve-week intervention period. The Capability, Opportunity, Motivation-Behaviour model and APEASE criteria were used to identify population-specific intervention functions, policy categories, behaviour change techniques and modes of intervention delivery. The resulting intervention was successful, increasing the average daily energy intake of the athlete to 24.5 MJ, which corresponded in a 6.2 kg body mass gain. Despite consuming 0.6 MJ less per day than targeted, secondary outcome measures of diet quality, strength, body composition and immune function all substantially improved, supporting a sufficient energy intake and the overall efficacy of a behavioural approach. Ultimately, the Behaviour Change Wheel provides sport nutrition professionals with an effective and practical step-wise method via which to design and implement effective nutritional interventions for use within high-performance sport