Physiological mechanisms associated with the use of a passive heat intervention: positive implications for soccer substitutes.

PURPOSE: Soccer substitutes are exposed to periods of limited activity before entering match-play, likely negating benefits of active warm-ups. This study aimed to determine the effects of using a passive heat intervention following a pre-match, and half-time warm-up, on muscle and core temperature in soccer players during ambient (18 °C) and cold (2 °C) conditions. METHODS: On four occasions, 8 male players, completed a pre-match warm-up, followed by 45 min of rest. Following this, participants completed a half-time re-warm-up followed by an additional 45 min of rest, simulating a full match for an unplaying substitute. During periods of rest, participants wore either standardised tracksuit bottoms (CON), or heated trousers (HEAT), over typical soccer attire. RESULTS: Vastus lateralis temperature declined less in HEAT compared to CON following the 1st half in 2 °C (Δ - 4.39 ± 0.81 vs. - 6.21 ± 1.32 °C, P = 0.002) and 18 °C (Δ - 2.48 ± 0.71 vs. - 3.54 ± 0.88 °C, P = 0.003). These findings were also observed in the 2nd half for the 2 °C (Δ - 4.36 ± 1.03 vs. - 6.26 ± 1.04 °C, P = 0.002) and 18 °C (Δ - 2.85 ± 0.57 vs. - 4.06 ± 1 °C, P = 0.018) conditions. In addition, core temperature declined less in HEAT compared to CON following the 1st (Δ - 0.41 ± 0.25 vs. - 0.84 ± 0.41 °C, P = 0.037) and 2nd (Δ - 0.25 ± 0.33 vs. - 0.64 ± 0.34 °C, P = 0.028) halves of passive rest in 2 °C, with no differences in the 18 °C condition. Perceptual data confirmed that participants were more comfortable in HEAT vs. CON in 2 °C (P < 0.01). CONCLUSIONS: Following active warm-ups, heated trousers attenuate the decline in muscle temperature in ambient and cold environments.

Investigation into the transition to online learning due to the COVID-19 pandemic, between new and continuing undergraduate students.

Higher Education Institutions (HEIs) were required to rapidly respond to the COVID-19 pandemic, integrating online and blended learning approaches to sustain teaching and learning provision. However, limited evidence exists to understand the student experience and perception of the various methods of online learning, in particular across different levels of study (new and continuing students). Therefore, the aim of this study was to compare the experiences of online learning transition, between new first year undergraduate students and continuing second and third year students, enrolled on various undergraduate sport programmes. A total of 182 students responded to an online survey, which investigated the students' perceptions of online learning approaches. Participants were split according to level of study; [Level 3 (Foundation Year) and 4 (First Year Undergraduate) combined N = 62, Level 5 (Second Year Undergraduate), N = 51 and Level 6 (Third Year Undergraduate), N = 69]. Key findings highlight that both new and continuing students had an overall negative perception of online learning but did acknowledge that online learning provided a more flexible approach to their overall learning experience compared to face-to-face. Face-to-face teaching was deemed more engaging and sociable, in particular for the practical aspects of the programmes. Overall, there were no significant differences between the different levels of study for any of the questions asked. Although continuing students raised the difficulties of conducting practical sessions online, whereas this was not mentioned by new students. To conclude, this study provides novel insights into the experience of new and continuing students, and we advise that future blended learning strategies should consider the programme as a whole, rather than tailoring pedagogic strategies based on the level of study.

The Effectiveness of Nutritional Education Interventions on Dietary Intake in Young Black Males: A Near-Empty Systematic Review.

The incidence of several diet and lifestyle-related diseases, previously seen only in adults, is increasing in prevalence in young people. The Black population, and particularly Black males, are at high risk of developing lifestyle-related diseases. Adolescence and young adulthood are considered a transitional period with increasing independence and responsibility, along with the development of lifelong lifestyle habits. This systematic review aimed to establish which methods and approaches to nutritional education interventions are the most effective in improving the nutritional/dietary intake in healthy young Black males. Eligibility criteria were designed using PICOS and included controlled trials of nutrition education interventions designed to improve dietary intake in healthy young Black or mixed-race males aged 14-21 years old. Medline, Cinahl and Scopus were searched in April 2021, resulting in 20,375 records being screened, and subsequently 72 full-text articles were reviewed. Risk of bias was assessed using the ROBINS-I tool. One study met the eligibility criteria. Results are presented in a narrative format as meta-analysis was not possible. This systematic review revealed a lack of evidence on the effectiveness of nutritional education interventions in this high-risk population. Limitations are noted and recommendations have been made.

Mobile applications for the sport and exercise nutritionist: a narrative review.

Mobile technology is widespread in modern society, and the applications (apps) that they run can serve various purposes. Features such as portability, ease of communication, storage, and relative low cost may make such technology attractive to practitioners in several fields. This review provides a critical narrative on the existing literature for apps relevant to the field of sport and exercise nutrition. Three main areas are discussed: (1) dietary analysis of athletes, (2) nutrition education for athletes, (3) estimating body composition. The key purpose of the review was to identify what literature is available, in what areas apps may have a benefit over traditional methods, and considerations that practitioners should make before they implement apps into their practice or recommend their use to coaches and athletes.

The effects of an increased calorie breakfast consumed prior to simulated match-play in Academy soccer players.

Dietary analysis of Academy soccer players highlights that total energy and carbohydrate intakes are less than optimal, especially, on match-days. As UK Academy matches predominantly kick-off at ∼11:00 h, breakfast is likely the last pre-exercise meal and thus may provide an intervention opportunity on match-day. Accordingly, the physiological and performance effects of an increased calorie breakfast consumed ∼135-min before soccer-specific exercise was investigated. English Premier League Academy soccer players (n = 7) repeated a 90-min soccer match simulation on two occasions after consumption of habitual (Bhab; ∼1100 kJ) or increased (Binc; ∼2100 kJ) energy breakfasts standardised for macronutrient contributions (∼60% carbohydrates, ∼15% proteins and ∼25% fats). Countermovement jump height, sprint velocities (15-m and 30-m), 30-m repeated sprint maintenance, gut fullness, abdominal discomfort and soccer dribbling performances were measured. Blood samples were taken at rest, pre-exercise, half-time and every 15-min during exercise. Although dribbling precision (P = .522; 29.9 ± 5.5 cm) and success (P = .505; 94 ± 8%) were unchanged throughout all time-points, mean dribbling speed was faster (4.3 ± 5.7%) in Binc relative to Bhab (P = .023; 2.84 vs 2.75 m s-1). Greater feelings of gut fullness (67 ± 17%, P = .001) were observed in Binc without changes in abdominal discomfort (P = .595). All other physical performance measures and blood lactate and glucose concentrations were comparable between trials (all P > .05). Findings demonstrate that Academy soccer players were able to increase pre-match energy intake without experiencing abdominal discomfort; thus, likely contributing to the amelioration of energy deficits on match-days. Furthermore, whilst Binc produced limited benefits to physical performance, increased dribbling speed was identified, which may be of benefit to match-play.

The Effects of 120 Minutes of Simulated Match Play on Indices of Acid-Base Balance in Professional Academy Soccer Players.

This study investigated the changes in indices of acid-base balance during 120 minutes of simulated soccer match play that included a 30 minute extra-time (ET) period. Eight English Premier League academy soccer players participated in a simulated soccer match that required varying intensities of intermittent exercise including 15-m sprints and soccer dribbling throughout. Blood samples were obtained before (i.e., baseline and pre-exercise) and throughout exercise (i.e., 15, 30, 45, 60, 75, 90, 105, and 120 minutes), and at half time. Sprint speeds over 15 m reduced in ET compared to the first half (-0.39 ± 0.37 m·s, -7 ± 6%, p = 0.021) but not the second half (-0.18 ± 0.25 m·s, -3 ± 4%, p = 0.086). At 105 minutes, blood lactate concentrations reduced compared with that in the opening 30 minutes (-0.9 to -1.2 mmol·L, p ≤ 0.05). Blood pH (-0.03 to -0.04 units), base excess (-0.95 to -1.48 mmol·L), and bicarbonate concentrations (-0.9 ± 0.8 mmol·L) were depressed at 120 minutes compared with those at 105 minutes, baseline and half time (all p ≤ 0.05). There were no significant correlations between changes in acid-base balance and sprint speed (all p > 0.05). Although the perturbations in acid-base balance during ET were statistically significant, the decreases in blood pH, lactate, base excess, and bicarbonate concentrations may not represent metabolic acidosis or impairments in buffering capacity that are likely to explain reduced physical performance. Further research is warranted to investigate mechanisms of fatigue during ET and to develop interventions that attenuate decrements in performance.

Physiological and performance effects of carbohydrate gels consumed prior to the extra-time period of prolonged simulated soccer match-play.

OBJECTIVES: The physiological and performance effects of carbohydrate-electrolyte gels consumed before the 30min extra-time period of prolonged soccer-specific exercise were investigated. DESIGN: Randomised, double-blind, crossover. METHODS: Eight English Premier League academy soccer players performed 120min of soccer-specific exercise on two occasions while consuming fluid-electrolyte beverages before exercise, at half-time and 90min. Carbohydrate-electrolyte (0.7±0.1gkg(-1) BM) or energy-free placebo gels were consumed ∼5min before extra-time. Blood samples were taken before exercise, at half-time and every 15min during exercise. Physical (15-m and 30-m sprint speed, 30-m sprint maintenance and countermovement jump height) and technical (soccer dribbling) performance was assessed throughout each trial. RESULTS: Carbohydrate-electrolyte gels improved dribbling precision (+29±20%) and raised blood glucose concentrations by 0.7±0.8mmoll(-1) during extra-time (both p<0.01). Supplementation did not affect sprint velocities (15m and 30m), 30-m sprint maintenance or dribbling speed as reductions compared to 0-15min values occurred at 105-120min irrespective of trial (all p<0.05). Plasma osmolality and blood sodium concentrations increased post-exercise vs. the opening 15min (p<0.05) but no effect of supplementation existed. Selected markers of physical performance (jump height, 30-m sprint velocity and 30-m repeated sprint maintenance) also reduced by >3% during half-time (all p<0.05). CONCLUSIONS: Carbohydrate-electrolyte gel ingestion raised blood glucose concentrations and improved dribbling performance during the extra-time period of simulated soccer match-play. Supplementation did not attenuate reductions in physical performance and hydration status that occurred during extra-time.

Assessment of Energy Intake and Energy Expenditure of Male Adolescent Academy-Level Soccer Players during a Competitive Week.

This study investigated the energy intake and expenditure of professional adolescent academy-level soccer players during a competitive week. Over a seven day period that included four training days, two rest days and a match day, energy intake (self-reported weighed food diary and 24-h recall) and expenditure (tri-axial accelerometry) were recorded in 10 male players from a professional English Premier League club. The mean macronutrient composition of the dietary intake was 318 ± 24 g·day(-1) (5.6 ± 0.4 g·kg(-1) BM) carbohydrate, 86 ± 10 g·day(-1) (1.5 ± 0.2 g·kg(-1) BM) protein and 70 ± 7 g·day(-1) (1.2 ± 0.1 g·kg(-1) BM) fats, representing 55% ± 3%, 16% ± 1%, and 29% ± 2% of mean daily energy intake respectively. A mean daily energy deficit of -1302 ± 1662 kJ (p = 0.035) was observed between energy intake (9395 ± 1344 kJ) and energy expenditure (10679 ± 1026 kJ). Match days (-2278 ± 2307 kJ, p = 0.012) and heavy training days (-2114 ± 2257 kJ, p = 0.016) elicited the greatest deficits between intake and expenditure. In conclusion, the mean daily energy intake of professional adolescent academy-level soccer players was lower than the energy expended during a competitive week. The magnitudes of these deficits were greatest on match and heavy training days. These findings may have both short and long term implications on the performance and physical development of adolescent soccer players.

Agreement between Two Methods of Dietary Data Collection in Male Adolescent Academy-Level Soccer Players.

Collecting accurate and reliable nutritional data from adolescent populations is challenging, with current methods providing significant under-reporting. Therefore, the aim of the study was to determine the accuracy of a combined dietary data collection method (self-reported weighed food diary, supplemented with a 24-h recall) when compared to researcher observed energy intake in male adolescent soccer players. Twelve Academy players from an English Football League club participated in the study. Players attended a 12 h period in the laboratory (08:00 h-20:00 h), during which food and drink items were available and were consumed ad libitum. Food was also provided to consume at home between 20:00 h and 08:00 h the following morning under free-living conditions. To calculate the participant reported energy intake, food and drink items were weighed and recorded in a food diary by each participant, which was supplemented with information provided through a 24-h recall interview the following morning. Linear regression, limits of agreement (LOA) and typical error (coefficient of variation; CV) were used to quantify agreement between observer and participant reported 24-h energy intake. Difference between methods was assessed using a paired samples t-test. Participants systematically under-reported energy intake in comparison to that observed (p < 0.01) but the magnitude of this bias was small and consistent (mean bias = -88 kcal·day(-1), 95% CI for bias = -146 to -29 kcal·day(-1)). For random error, the 95% LOA between methods ranged between -1.11 to 0.37 MJ·day(-1) (-256 to 88 kcal·day(-1)). The standard error of the estimate was low, with a typical error between measurements of 3.1%. These data suggest that the combined dietary data collection method could be used interchangeably with the gold standard observed food intake technique in the population studied providing that appropriate adjustment is made for the systematic under-reporting common to such methods.

A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players.

Reduced physical performance has been observed following the half-time period in team sports players, likely due to a decrease in muscle temperature during this period. We examined the effects of a passive heat maintenance strategy employed between successive exercise bouts on core temperature (Tcore) and subsequent exercise performance. Eighteen professional Rugby Union players completed this randomised and counter-balanced study. After a standardised warm-up (WU) and 15 min of rest, players completed a repeated sprint test (RSSA 1) and countermovement jumps (CMJ). Thereafter, in normal training attire (Control) or a survival jacket (Passive), players rested for a further 15 min (simulating a typical half-time) before performing a second RSSA (RSSA 2) and CMJ's. Measurements of Tcore were taken at baseline, post-WU, pre-RSSA 1, post-RSSA 1 and pre-RSSA 2. Peak power output (PPO) and repeated sprint ability was assessed before and after the simulated half-time. Similar Tcore responses were observed between conditions at baseline (Control: 37.06±0.05°C; Passive: 37.03±0.05°C) and for all other Tcore measurements taken before half-time. After the simulated half-time, the decline in Tcore was lower (-0.74±0.08% vs. -1.54±0.06%, p<0.001) and PPO was higher (5610±105 W vs. 5440±105 W, p<0.001) in the Passive versus Control condition. The decline in PPO over half-time was related to the decline in Tcore (r = 0.632, p = 0.005). In RSSA 2, best, mean and total sprint times were 1.39±0.17% (p<0.001), 0.55±0.06% (p<0.001) and 0.55±0.06% (p<0.001) faster for Passive versus Control. Passive heat maintenance reduced declines in Tcore that were observed during a simulated half-time period and improved subsequent PPO and repeated sprint ability in professional Rugby Union players.