Nutrition in team sports

Changes in Body Composition and Nutritional Periodization during the Training Macrocycle in Football-A Narrative Review

Nutrition periodization in football training is an important determinant of adaptation to cyclic training loads. Personalizing an athlete's diet is crucial to ensure optimal performance and body composition, depending on the phase of training. The purpose of this review is to answer the question of how the body composition of football players changes over the training macrocycle and how dietary recommendations should be tailored to specific training periods. The review of scientific evidence was conducted based on the available literature, typing in phrases related to training and nutrition periodization using the PubMed and Google Scholar database methodology tools. A literature search resulted in the selection of 346 sources directly related to the topic of the study, and then those with the highest scientific value were selected. There is a need to adjust energy and nutrient intake according to the different training phases in a football player's preparation cycle. During the preparatory phase, it is recommended to increase protein and energy intake to support anabolic processes and muscle mass development. During the competitive period, due to the intensity of matches and training, the importance of carbohydrates for glycogen replenishment and recovery is emphasized. The transition phase requires the regulation of caloric intake to prevent adverse changes in body composition. Hydration has been identified as a key element in each phase of training. Cooperation between coaches, nutritionists, and players is essential to optimize sports performance and rapid recovery, and the authors recommend continuous adaptation and nutritional optimization as an integral part of football training.

Supplement Consumption by Elite Soccer Players: Differences by Competitive Level, Playing Position, and Sex

Soccer is a sport practiced all over the world and whose practice begins in young athletes. Currently, the consumption of nutritional supplements is essential to achieve the maximum performance of players. The aim of this study was to describe the consumption of sports supplements (CSS) by elite soccer players and its association with their competitive level, playing position, and sex. A comparative descriptive and non-experimental study was performed during the 2021-2022 competitive season. A total of 70 elite players completed one online questionnaire about their CSS. We found that sports drinks (55.7%), sports bars (50.0%), whey protein (48.6%), caffeine (47.1%), and creatine (60.0%) were the most consumed supplements by the total sample. Relative to the categories, the CSS was higher in the senior teams for both men and women. Regarding playing positions, caffeine was more consumed by midfielders and forwards (p = 0.013). Finally, in relation to sex, significant differences were found in the consumption of sports confectionery (p = 0.036), whey protein (p = 0.002), β-alanine (p = 0.013), and melatonin (p = 0.016). Soccer club SS questionnaires gather data to understand patterns, assess effectiveness and risks, and aid research. In conclusion, differences were found in the CSS according to competitive level, sex, and playing position.

Pattern of Consumption of Sports Supplements of Spanish Handball Players: Differences According to Gender and Competitive Level

(1) Background: Given the physiological characteristics of handball, players may require the use of certain sports supplements (SS). However, very few studies have investigated the consumption of SS in handball. The aims were to determine the number of handball players who consume SS, to analyze their SS consumption pattern according to gender and competitive level, and to assess whether the SS they consume are supported by scientific evidence, and to which group they belong according to the classification of the Australian Institute of Sport (AIS). (2) Methods: A descriptive-correlational study was carried out on the habitual consumption of SS in 360 federated Spanish players by using a self-administered and validated questionnaire. (3) Results: These showed 65.8% of the sample consumed SS. According to the total number of participants, the most consumed supplements were from Group A: sports drinks (30.8%) and whey protein (30.4%). When analyzing the data by gender, the men's consumption was significantly higher for whey protein (p < 0.001), caffeine (p = 0.009), and creatine monohydrate (p < 0.001). When analyzed by competitive level, the provincial category players group showed a significantly lower consumption than the rest of the groups for protein bars (p = 0.038), whey protein (p = 0.005) and creatine monohydrate (p < 0.001), while the honor division group showed a significantly higher intake of creatine monohydrate than the remaining groups (p < 0.001). (4) Conclusions: The handball players showed a moderate consumption of SS, without using substances that were not supported by scientific evidence and opting in most cases for supplements belonging to group A from the AIS classification. Men tended to consume more SS, and SS consumption increased based on competitive level.

Effects of exchange vs. controlled diet on biochemical, body composition and functional parameters in elite female soccer players

Due to the increasing level of professionalism, the high frequency of competitions, and the alarming injury rate observed in elite female soccer players, multidisciplinary strategies, including nutritional monitoring, need to be implemented. This study aimed to quantify energy, macronutrient and micronutrient intakes during the competitive period and to analyze the effects of two different nutritional interventions on nutritional knowledge, anthropometric data, biochemical values and physical performance. 19 elite female soccer players were randomly divided into two groups: the controlled-diet group (CG, n = 10), that followed a diet based on pre-established menus, and the exchange-diet group (EG, n = 9), that designed their own menus with an exchanged list. A cross-sectional study was designed to evaluate the dietary intake, while an experimental randomized controlled trial was designed to compare the effects of both 12-week nutritional interventions. Total energy, CHO, PROT, fibre and micronutrients intakes were below the general recommendations for athletes while, total and saturated fat intakes were above these. Moreover, there were no differences in diet during weekdays, pre-competition and competition days. The study also revealed a low nutritional knowledge and exchanged diet has demonstrated to be a better strategy to improve this. Biochemical monitoring showed that participants presented decreased concentration of haemoglobin and controlled diet may lead to greater effects on haemoglobin concentration and in anemia prevention. Both EG and CG showed significant reduction on skinfolds sum after intervention, but no significant differences were observed in thigh and calf indices. However, no significant changes were observed in soccer-related skills for any group.

Continuous Monitoring of Interstitial Fluid Glucose Responses to Endurance Exercise with Different Levels of Carbohydrate Intake

We compared the 24 h changes in interstitial fluid glucose concentration (IGC) following a simulated soccer match between subjects consuming a high-carbohydrate (HCHO; 8 g/kg BW/day) diet and those consuming a moderate-carbohydrate (MCHO; 4 g/kg BW/day) diet. Eight active healthy males participated in two different trials. The subjects were provided with the prescribed diets from days 1 to 3. On day 3, the subjects performed 90 min (2 bouts × 45 min) of exercise simulating a soccer match. The IGC of the upper arm was continuously monitored from days 1 to 4. No significant difference in the IGC was observed between trials during exercise. The total area under the curve (t-AUC) value during exercise did not significantly differ between the HCHO (9719 ± 305 mg/dL·90 min) and MCHO (9991 ± 140 mg/dL·90 min). Serum total ketone body and beta-hydroxybutyrate concentrations were significantly higher in the MCHO than in the HCHO after a second bout of exercise. No significant differences in the IGC were observed between trials at any time point during the night after exercise (0:00-7:00). In addition, t-AUC value during the night did not significantly differ between the HCHO (32,378 ± 873 mg/dL·420 min) and MCHO (31,749 ± 633 mg/dL·420 min). In conclusion, two days of consuming different carbohydrate intake levels did not significantly affect the IGC during a 90 min simulated soccer match. Moreover, the IGC during the night following the exercise did not significantly differ between the two trials despite the different carbohydrate intake levels (8 vs. 4 g/kg BW/day).

Dietary Habits of Elite Soccer Players: Variations According to Competitive Level, Playing Position and Sex

Soccer is a sport practiced worldwide by both men and women, where nutrition plays a fundamental role in the performance of soccer players, providing them with the nutrients necessary for energy, muscle recovery and injury prevention. The aim of this study is to describe the dietary habits in elite soccer players and their association with their competitive level, playing position and sex. A descriptive and non-experimental comparative study was conducted during the 2021-2022 competitive season. A total of 105 players belonging to a Spanish elite soccer team completed a food frequency questionnaire (FCFQ). It was observed that male players presented a higher consumption of carbohydrate-rich foods (p < 0.05), fermented foods (p = 0.014), frozen foods (p = 0.049) and red meat (p = 0.012) compared to female players, with the exception of lean meats, which were higher in females (p = 0.012). Furthermore, the U16-15 categories stand out for consuming carbohydrate-rich foods such as pasta (p = 0.000), bread (p = 0.004) and sweets (p = 0.046), as well as frozen foods (p = 0.002). Finally, alcohol consumption is higher in the senior categories (42.9%), where men are more likely to drink mixed drinks (6.2%), and beer and wine by women (10.7%). Practically no differences were found between the playing positions. In conclusion, differences were found in FCFQ according to competitive level and sex.

Prevalence of adulteration in dietary supplements and recommendations for safe supplement practices in sport

The prevalence of dietary supplement use among athletes continues to rise with 60-80% of athletes often reporting current or previous use of dietary supplements. While select dietary ingredients have been shown to improve acute performance and enhance training adaptations over time, it is important to still consider the risk vs. reward for athletes before opting to consume a dietary supplement. Previous work has indicated that certain dietary supplements may pose risks for inadvertent doping, may be susceptible to mislabelling, could be banned by certain governing bodies of sport, or pose health risks for certain populations. The purpose of the current narrative review is to summarize the prevalence of adulteration in dietary sport supplement products, outline the risks of inadvertent doping for athletes, and highlight best practices regarding safe supplementation strategies. Analytical studies have found anywhere from 14 to 50% of samples analyzed from dietary supplement products have tested positive for anabolic agents or other prohibited substances. It is important for the consumer to adhere to safe supplementation strategies, which include following serving size recommendations, cross-referencing ingredient profiles with the list of prohibited substances, choosing quality products that have been verified by a third-party certification program, and being cognizant of consuming multiple dietary supplement products with overlapping ingredient profiles. Once these practices have been considered, it is reasonable for an athlete to utilize dietary supplements as a strategy to optimize performance and health, with a low risk of failing a drug test (adverse analytical finding) and experiencing adverse events.

Adherence to the Mediterranean diet in young male soccer players

INTRODUCTION

Nutrition is vital in health and sports performance by improving anthropometric-related parameters and dietary habits, especially in the youngest ages. The Mediterranean diet (MD) has been highly recognized for its positive health effects and low adverse environmental impact.

OBJECTIVES

We aimed to characterize adherence to the MD and analyze its association with anthropometric parameters in young soccer players.

METHODOLOGY

In the present study, 132 male young soccer players from under 9 to under 15 categories (aged 7 to 15 years) from a Portuguese football club participated. The Mediterranean Diet Quality Index for Children and Adolescents (KIDMED) questionnaire was applied to assess adherence to the MD. Anthropometric-related parameters, including body mass, height, triceps skinfold thickness (TSKF), suprailiac skinfold thickness (SISKF), body mass index (BMI) and body fat percentage (%BF), were determined. The differences between groups were performed accordingly to normal and non-normal distribution. Spearman's correlations were performed to analyze the hypothetical correlation between KIDMED and BMI.

RESULTS

Players reached an average KIDMED score of 8.36 ± 1.92, showing that 68.2% (n = 90) reached high adherence to the MD, 31.1% (n = 41) had moderate adherence to the MD, and 0.78% (n = 1) had poor adherence to the MD. When the analysis was made for age group and BMI classification, no significant differences were observed in adherence to the MD. Considering the main characteristics of the MD, 50.8% consumed fruit (vs. 49,2%), 52.3% consumed vegetables (vs. 47,7%), and only 20% consumed oleaginous dried fruits (vs. 80%). Dairy consumption throughout the day was 49,2% (vs. no: 50,8%).

CONCLUSION

Data from the present study showed that many soccer players adhered to the MD, and no differences were observed for age group or BMI classification.

Cooking and food skills confidence of team sport athletes in Ireland

Nutritional support often focuses on cooking and food skills such as food selection, recipe planning and meal preparation. Individuals with greater cooking and food skills confidence have previously displayed higher diet quality scores and lower intakes of overall calories, saturated fat and sugar. Despite this, the cooking and food skills of team sport athletes have yet to be investigated. This study aimed to evaluate the relationship between cooking and food skills confidence and athletes' demographic characteristics. A validated measure for the assessment of cooking and food skills confidence was distributed via an online survey. Participants were required to rate their confidence on a Likert scale (1 "very poor" - 7 "very good") for 14 items related to cooking skills and 19 items for food skills. Food engagement, general health interest and self-reported fruit and vegetable consumption as a measure of diet quality were also measured. The survey was completed by 266 team sport athletes (male: 150, female: 116, age: 24.8 ± 6.1 years). Group differences were explored using t-tests and ANOVA and associations were evaluated using Spearman's correlation and hierarchical multiple regressions. Athletes' total cooking and food skills confidence was 62.7 ± 17.4 (64.0 ± 17.8%) and 83.8 ± 20.1 (63.0 ± 15.1%), respectively. Females reported greater confidence in both cooking (+20.3%, p < 0.01) and food skills (+9.2%, p < 0.01). Hierarchical multiple regressions explained 48.8% of the variance in cooking skills confidence and 44% of the variance in food skills confidence with gender, previous culinary training, cooking learning stage, general health interest and food engagement all remaining significant in the cooking skills confidence model and cooking frequency, previous culinary training, general health interest and food engagement remaining significant in the food skills confidence model. Male team sport athletes may benefit the most from educational interventions designed to increase cooking and food skills confidence.

Prevalence of low energy availability and associations with seasonal changes in salivary hormones and IgA in elite male Gaelic footballers

PURPOSE

Evidence suggests low energy availability (LEA) is prevalent in elite male Gaelic football (GF) players. Previous research in male and female team sports found LEA may negatively impact endocrine function. The aim of this study was to examine the seasonal variations in energy availability (EA) and its associations with salivary measures in elite male GF players across the competitive season.

METHODS

Energy availability was assessed using field-based methods in conjunction with salivary testosterone (s-T), cortisol (s-C) and immunoglobin A (s-IgA) concentrations at pre-season (PRE), in-season (IN) and post-season (POST).

RESULTS

38% reported LEA at PRE, 33% at IN, and 28.5% at POST. s-C, s-T and s-IgA levels were within normal ranges at PRE, IN and POST. Salivary cortisol declined significantly from PRE to IN, remaining reduced at POST. Salivary testosterone decreased significantly from PRE to IN but was significantly elevated at POST compared to IN. Salivary IgA was significantly greater at POST than IN. No significant associations were found between s-C or s-T and EA at any time point. Pre-season s-IgA exhibited a significant inverse association with PRE EA. Decreased s-IgA flow rate and s-IgA secretion rate were significantly associated with decreased EA at PRE. Reduced carbohydrate (CHO) intake was also associated with decreased s-IgA secretion rate at PRE.

CONCLUSION

This study suggests that LEA is prevalent in elite male GF players, but is not associated with s-C or s-T. However, EA is associated with s-IgA which may impact the immune system. Therefore, education and interventions surrounding the prevalence and associations of EA should be implemented in this population.

Energy availability and macronutrient intake in elite male Gaelic football players

Evidence suggests that Gaelic football (GF) players do not meet the recommended energy intake (EI) levels and therefore may be at risk of low energy availability (LEA). This study examined energy availability (EA) in 20 elite male GF players. At two stages during a season (2019-2020), repeated measures of EI, exercise energy expenditure (EEE), EA and body composition were performed. Sixty-five percent reported with LEA [<30 kcal.kg Lean Body Mass (LBM)^-1.day^-1] at pre-season (PRE), with 70% at in-season (IN). Mean daily carbohydrate intake (PRE 3.2 ± 0.82 g.kg; IN 3.4 ± 0.79 g.kg) was below the recommended intake (5-7 g.kg) in 95% at PRE and 100% at IN. All consumed the recommended daily amount of protein (PRE 1.85 ± 0.57 g.kg; IN 1.87 ± 0.48 g.kg) and fat (PRE 1.23 ± 0.4 g.kg; IN 1.02 ± 0.3 g.kg). Significant correlations (P = 0.001) were reported between EA and carbohydrates (PRE r = 0.801; IN r = 0.714); protein (PRE r = 0.675; IN r = 0.769); fat (PRE r = 0.805; IN r = 0.733) and energy intake (PRE r = 0.960; IN r = 0.949). Twenty percent were at risk of disordered eating. This study suggests male elite GF players require education and interventions surrounding nutrition, in particular EA.

Metabolic and Body Composition Changes in Ice Hockey Players Using an Ergogenic Drug (Cytoflavin)

BACKGROUND AND OBJECTIVES

In ice hockey, the major physical workload comes from acceleration in all planes of motion and transitions between skating trajectories. Hockey players' anthropometric characteristics correlate with performance. In team sports, the use of ergogenic drugs for recovery is relevant to avoid athletes' overtraining. It is very important to protect athletes' health and allow them to maintain high-performance levels. Cytoflavin is an ergogenic drug whose action is based on the combined effects of its active ingredients (succinic acid, inosine, nicotinamide and riboflavin), which are naturally occurring metabolites that stimulate tissue respiration. The study aimed to assess the 6-week Cytoflavin consumption effects on body composition (body weight, body mass index, body fat percentage and bioimpedance phase angle) and aerobic performance.

METHODS

This study included 60 male professional hockey players (aged 19 to 36 years) divided into two groups of 30 subjects: group I (body weight 87.90 ± 7.44 kg, BMI 25.86 ± 2.04 kg/m²) and group II (body weight 87.04 ± 6.22 kg, BMI 25.52 ± 2.38 kg/m²). Athletes in group I received Cytoflavin, whereas athletes in group II did not.

RESULTS

In group I, statistically significant reductions in body weight and body mass index were not observed until 14 and 35 days, respectively. In contrast, in group II, both body weight and BMI significantly decreased both times. Aerobic performance significantly increased in both groups, with significantly greater increases in group I.

CONCLUSIONS

Cytoflavin can be considered an ergogenic drug that improves body composition parameters, especially in the control of weight reduction and improvement in aerobic performance.

A randomized open-labeled study to examine the effects of creatine monohydrate and combined training on jump and scoring performance in young basketball players

Background

Creatine monohydrate (CrM) supplementation has been shown to be an effective and safe nutritional supplement to improve performance; however, the impact of CrM supplementation in young basketball players is less clear. This study evaluated the effects of CrM supplementation during a strength and conditioning training (SCT) program on lower-limb strength parameters and performance in under-16 (U16) basketball players.

Methods

Twenty-three male U16 basketball players participated in this study (14.3 ± 0.4 years; BMI: 20.7 ± 2.2 kg∙m⁻²). The players were randomly assigned to either a CrM group (n = 12) that ingested 0.1 g·kg⁻¹·day⁻¹ of CrM or to a non-supplemented control group (n = 11, CON). The athletes participated in an 8-week SCT program consisting of two lower-limb resistance-training sessions and two plyometric sessions per week. Squat jump (SJ), drop jump (DP), countermovement jump (CMJ), and Abalakov (ABK) jump power tests as well as basketball performance (points and minutes per game) were measured before, during and/or after the intervention. Data were analyzed using a general linear model with repeated measures with independent Student’s t-test pairwise comparisons.

Results

The results (95% confidence interval for mean change from baseline) show that there were significant differences for all variables for CrM and CON, respectively: SJ (cm): 2.6 – 6.4, P < 0.01 and 2.2–5.1 P < 0.01; DJ (cm): 2.5–5.6, P < 0.01, and 1.8–4.4, P < 0.01; CMJ (cm): 0.3–0.8, P < 0.01, and 0.2–0.5, P < 0.01; ABK (cm): 2.8–5.5, P < 0.01 and 0.7–2.6, P = 0.003. A significant group x time interaction (p = 0.003, η_p² = 0.342) was observed in ABK performance. No significant group x time effects were seen in squat jump (p = 0.449, η_p² = 0.028), drop jump (p = 0.143, η_p² = 0.099), or counter movement jump (p = 0.304, η_p² = 0.05). A significant interaction effect was also observed in points per game (p = 0.049, η_p² = 0.149), while a non-significant but medium effect was seen in minutes per game (p = 0.166, η_p² = 0.094).

Conclusions

CrM supplementation in conjunction with resistance and plyometric training increased the lower-limb ABK power and scoring performance in U16 basketball players.

Energy and Macronutrients Intake in Indoor Sport Team Athletes: Systematic Review

Indoor team sports are characterized by matches that are shorter in duration and with frequent substitution (high-intensity intermittent). The main goal of teams is to best cover athletes' physiological demands, while meeting their dietary intake needs is critical. The aim of this study is to conduct a systematic review of the dietary intake of indoor team sports athletes and to analyze whether they comply with nutritional recommendations. A search of PubMed-MEDLINE, Web of Science, and Scopus databases from 2008 to July 2022 was conducted and 2727 documents were identified. The studies focused on adult professional or semi-professional volleyball, basketball, handball, or futsal athletes. Two independent researchers screened and extracted the data, with 20 documents included after they met the inclusion criteria. Most of the athletes, both men and women, did not meet the official recommendations based on under-consumption (energy and carbohydrates) or over-consumption (fats). In relation to protein, 28.6% of studies met the recommendations, with 50% of those who did not meet it being due to under-consumption. Although there are references on athletes' dietary intakes, there are no references considering sexes or types of sport. More adapted recommendations are needed in order to more precisely evaluate athletes' intake to know if they meet their real nutritional requirements.

Dietary Intake of Young Male Ice Hockey Players 10-13 Years of Age during a Week-Long Hockey Camp

This study recorded the dietary intakes of young male ice hockey players (10-13 year (yr)) for 3 consecutive days while participating in a 5-day summer hockey camp. Players were categorized as older children (OC, n = 10; 10.7 ± 0.2 yr; 37.1 ± 1.5 kg; 147.9 ± 2.1 cm) and young adolescents (YA, n = 10; 12.9 ± 0.1 yr; 45.2 ± 1.5 kg; 157.0 ± 2.4 cm). Players consumed their usual daily intakes. Parents recorded food intake in the mornings and evenings, while the researchers recorded food intake at camp. Energy intake was higher in both groups when compared to data for age-matched young Canadian (CDN) males (OC, 2967 ± 211 vs. 2000 kcal/day; YA, 2773 ± 91 vs. 2250 kcal/day). Carbohydrate (CHO) (OC, 11.2 ± 0.8 vs. YO, 8.9 ± 0.5 g/kg body mass/day) and protein (OC, 3.2 ± 0.3; YO, 2.4 ± 0.1 g/kg/day) intakes were higher than reported for young CDN males (CHO, 3.6 and protein, 1.0 g/kg/day) and were within the Acceptable Macronutrient Distribution Range (AMDR; CHO, 56 ± 2.3; 57.4 ± 0.8%; protein, 16.1 ± 1.0; 15.7 ± 0.7%). Fat intake was also within the AMDR in both groups (OC, 29.8 ± 1.6%; YA, 28.3 ± 1.0%). Micronutrient intake was adequate except for Vitamin D intakes that were below the recommended 15 ug/day at 6.3 ± 0.7 (OC) and 5.0 ± 1.5 ug/day (YA). In summary, energy and macronutrient intakes of the OC (10-11 yr) and YA (12-13 yr) players were high and well above the age matched CDN norms. The older children had higher energy intakes/kg body mass than the young adolescents. Higher energy intakes allowed for micronutrients intakes to be met in these young active males, except for vitamin D intake.

A Multidisciplinary Approach to Game Day Preparation for Team Sports: A Delphi Study With Expert Consensus

ABSTRACT

Mason, BRJ, Pumpa, KL, McKune, AJ, Gill, ND, and Ball, NB. A multidisciplinary approach to game day preparation for team sports: A Delphi study with expert consensus. J Strength Cond Res 36(5): 1345-1352, 2022-The aim of this study was to identify game day preparation strategies used by performance staff to improve team sport performance and to determine consensus regarding the application and importance of these strategies. Twenty-five performance staff working in high performance or professional team sports participated in this Delphi study, which implemented 3 survey rounds. The first round sought responses to open-ended questions relating to the use of game day preparation strategies. These responses were developed into statements and recirculated (round-2 survey), with subjects asked to rate their level of agreement with each statement. The third and final survey presented revised versions of statements that did not reach a consensus in the previous round, along with new statements derived from subject responses. A thematic analysis of the open-ended responses in the first survey identified 5 key themes relating to game day preparation strategies: "exercise," "nutrition," "psychological," "technical and tactical," and "other." The round-2 survey included 38 statements across the 5 themes, with 22 reaching the consensus threshold (≥75%) for agreement. The remaining 16 statements did not reach consensus. The final survey included 18 statements (16 revised and 2 new) with 12 reaching the consensus threshold for agreement. Key preparation strategies identified in this study include structured and progressive warm-ups, strength and power-based priming sessions, individualized nutrition plans, and precooling in hot conditions. Performance staff working in similar environments should consider adopting these strategies to improve athlete or team performance.

Energy Requirements and Nutritional Strategies for Male Soccer Players: A Review and Suggestions for Practice

Soccer is a high intensity intermittent sport, featuring critical events completed at high/maximal intensity which is superimposed onto an aerobic base of lower intensity activities and rest. Due to these varying energic demands and the duration of competition the need for optimal nutritional strategies to offset and delay fatigue are paramount. Over the last 50 years, several investigations have been reported on aspects of soccer be they nutrition-focused or those concerning the demands of the sport. Emanating from these scientific papers, observations have been made on the likely factors which result in the fatigue during match-play. Factors such as muscle glycogen depletion and hypoglycaemia are discussed. Studies on the energy demands of soccer have employed a variety of methodologies which are briefly reviewed and vary between the use of heart rate telemetry to the use of global positioning systems (GPS). Moving on from observations of the energy demands of the sport leads to the major focus of this review which highlights key nutritional strategies to support the preparation and recovery of male soccer players to enhance performance, or at least to enable players to perform adequately. This review examines relevant methodologies in assessing training and competitive energy costs as well as the concomitant energy intakes demanded for successful performance outcomes. In order to bring an applied aspect to the overall findings from areas discussed, some practical ideas of feeding strategies are presented.

In-Season Nutrition Strategies and Recovery Modalities to Enhance Recovery for Basketball Players: A Narrative Review

Basketball players face multiple challenges to in-season recovery. The purpose of this article is to review the literature on recovery modalities and nutritional strategies for basketball players and practical applications that can be incorporated throughout the season at various levels of competition. Sleep, protein, carbohydrate, and fluids should be the foundational components emphasized throughout the season for home and away games to promote recovery. Travel, whether by air or bus, poses nutritional and sleep challenges, therefore teams should be strategic about packing snacks and fluid options while on the road. Practitioners should also plan for meals at hotels and during air travel for their players. Basketball players should aim for a minimum of 8 h of sleep per night and be encouraged to get extra sleep during congested schedules since back-to back games, high workloads, and travel may negatively influence night-time sleep. Regular sleep monitoring, education, and feedback may aid in optimizing sleep in basketball players. In addition, incorporating consistent training times may be beneficial to reduce bed and wake time variability. Hydrotherapy, compression garments, and massage may also provide an effective recovery modality to incorporate post-competition. Future research, however, is warranted to understand the influence these modalities have on enhancing recovery in basketball players. Overall, a strategic well-rounded approach, encompassing both nutrition and recovery modality strategies, should be carefully considered and implemented with teams to support basketball players' recovery for training and competition throughout the season.

Portuguese Football Federation consensus statement 2020: nutrition and performance in football

Nutrition is an undeniable part of promoting health and performance among football (soccer) players. Nevertheless, nutritional strategies adopted in elite football can vary significantly depending on culture, habit and practical constraints and might not always be supported by scientific evidence. Therefore, a group of 28 Portuguese experts on sports nutrition, sports science and sports medicine sought to discuss current practices in the elite football landscape and review the existing evidence on nutritional strategies to be applied when supporting football players. Starting from understanding football's physical and physiological demands, five different moments were identified: preparing to play, match-day, recovery after matches, between matches and during injury or rehabilitation periods. When applicable, specificities of nutritional support to young athletes and female players were also addressed. The result is a set of practical recommendations that gathered consensus among involved experts, highlighting carbohydrates periodisation, hydration and conscious use of dietary supplements.

Dietary Macronutrient and Micronutrient Intake over a 7-Day Period in Female Varsity Ice Hockey Players

This study examined the energy, macronutrient, and micronutrient intakes of female ice hockey players over a 7-d period including game, practice, and rest days. Twenty-three female varsity players (19.0 ± 1.1 yr, 167.1 ± 6.5 cm, 67.0 ± 8.0 kg) volunteered for the study. Average total daily energy expenditure (TDEE) was estimated over the 7-day period. Average 7-day energy intake (EI) and TDEE were 2354 ± 353 and 2304 ± 204 kcal. The majority (n = 19) of athletes had an EI ≥ 90% of their estimated TDEE. Macronutrient intake was 52% carbohydrate (CHO), 32% fat, and 16% protein of total EI, although CHO intake was slightly below recommendations (5 g/kg BM/d) on game and practice (4.8 ± 1.4 and 4.5 g/kg BM/d) days. Game day EI was greater than practice and rest days. Recommended micronutrient intakes were not met by most athletes for iron, calcium, vitamin D, and potassium, and intakes were similar between game, practice, and rest days. In summary, the average EI for female varsity ice hockey players appeared adequate to meet their energy needs over a weekly cycle of game, practice, and rest days. However, these female athletes would benefit from increasing CHO intake on game and practice days and selecting foods that are rich in vitamins and minerals.

The Influence of Sport Nutrition Knowledge on Body Composition and Perceptions of Dietary Requirements in Collegiate Athletes

Sport nutrition knowledge has been shown to influence dietary habits of athletes. The purpose of the current study was to examine relationships between sport nutrition knowledge and body composition and examine potential predictors of body weight goals in collegiate athletes. Participants included National Collegiate Athletic Association Division III women (n = 42, height: 169.9 ± 6.9 cm; body mass: 67.1 ± 8.6 kg; fat-free mass: 51.3 ± 6.6 kg; body fat percent: 24.2 ± 5.3%) and men (n = 25, height: 180.8 ± 7.2 cm; body mass: 89.2 ± 20.5 kg; fat-free mass: 75.9 ± 12.2 kg; body fat percent: 13.5 ± 8.9%) athletes. Body composition was assessed via air displacement plethysmography. Athletes completed a validated questionnaire designed to assess sport nutrition knowledge and were asked questions about their perceived dietary energy and macronutrient requirements, as well as their body weight goal (i.e., lose, maintain, gain weight). Athletes answered 47.98 ± 11.29% of questions correctly on the nutrition questionnaire with no differences observed between sexes (men: 49.52 ± 11.76% vs. women: 47.03 ± 11.04%; p = 0.40). An inverse relationship between sport nutrition knowledge scores and body fat percentage (BF%) (r = −0.330; p = 0.008), and fat mass (r = −0.268; p = 0.032) was observed for all athletes. Fat mass (β = 0.224), BF% (β = 0.217), and body mass index (BMI) (β = 0.421) were all significant (p < 0.05) predictors of body weight goal in women. All athletes significantly (p < 0.001) underestimated daily energy (−1360 ± 610.2 kcal/day), carbohydrate (−301.6 ± 149.2 grams/day [g/day]), and fat (−41.4 ± 34.5 g/day) requirements. Division III collegiate athletes have a low level of sport nutrition knowledge, which was associated with a higher BF%. Women athletes with a higher body weight, BF% and BMI were more likely to select weight loss as a body weight goal. Athletes also significantly underestimated their energy and carbohydrate requirements based upon the demands of their sport, independent of sex.

How Does the Dietary Intake of Female Field-Based Team Sport Athletes Compare to Dietary Recommendations for Health and Performance? A Systematic Literature Review

Field-based team sports present large energetic demands given their intermittent high-intensity nature. Current evidence suggests that the dietary intake of female athletes may be insufficient to meet such demands, resulting in negative consequences for athletic performance and health. The primary aim of this review was to therefore assess the adequacy of dietary intake of female field-based team sport athletes when compared to dietary recommendations. A systematic search of databases, including PubMed, Web of Science, SPORTDiscus, and OpenGrey, was performed from the earliest record available until July 2020, obtaining an initial total of 2588 articles. To be included within the final review, articles were required to provide a quantitative assessment of baseline dietary intake specific to the target population. A total of 20 studies (n = 462) met the full eligibility criteria. A majority reported that the dietary intake of female field-based team sport athletes was insufficient in overall energy (2064 ± 309 kcal·day^-1), carbohydrate (4.3 ± 1.2 g·kg·day^-1), and iron intake (13.6 ± 6.2 mg·day^-1) when compared to recommendations. Future research is required to establish why female team sport athletes consistently demonstrate deficient dietary practices, and to explore the potential negative consequences of this.

The 4R's Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates

Post-exercise recovery is a broad term that refers to the restoration of training capacity. After training or competition, there is fatigue accumulation and a reduction in sports performance. In the hours and days following training, the body recovers and performance is expected to return to normal or improve. ScienceDirect, PubMed/MEDLINE, and Google Scholar databases were reviewed to identify studies and position declarations examining the relationship between nutrition and sports recovery. As an evidence-based framework, a 4R’s approach to optimizing post-exercise recovery was identified: (i) Rehydration—a fundamental process that will depend on the athlete, environment and sports event; (ii) Refuel—the consumption of carbohydrates is not only important to replenish the glycogen reserves but also to contribute to the energy requirements for the immune system and tissue reparation. Several bioengineered carbohydrates were discussed but further research is needed; (iii) Repair—post-exercise ingestion of high-quality protein and creatine monohydrate benefit the tissue growth and repair; and (iv) Rest—pre-sleep nutrition has a restorative effect that facilitates the recovery of the musculoskeletal, endocrine, immune, and nervous systems. Nutritional consultancy based on the 4R’s is important for the wise stewardship of the hydration, feeding, and supplementation strategies to achieve a timely recovery.

Addition of Caffeine to a Carbohydrate Feeding Strategy Prior to Intermittent Exercise

The ergogenic effect of caffeine is well established, although no investigations providing a high carbohydrate feeding strategy (pre-exercise meal=2 g/kg BM) co-ingested with caffeine exist for soccer. This investigation examines the effect of caffeine in addition to a pre-exercise carbohydrate meal and drink mid-way through a soccer simulation. Eight recreational soccer players completed an 85-minute soccer simulation followed by an exercise capacity test (Yo-yo Intermittent Endurance test level 2) on two occasions. Prior to exercise participants consumed a high carbohydrate meal, with placebo or 5 mg/kg BM_-1 caffeine. No significant performance effect was identified (p=0.099) despite a 12.8% (109 m) improvement in exercise capacity following caffeine. Rates of carbohydrate and fat oxidation did not differ between conditions and nor were differences apparent for plasma glucose, fatty acids, glycerol, β-hydroxybutyrate (p>0.05). However, an increase in lactate was observed for caffeine (p=0.039). A significant condition effect on rating of perceived exertion was identified (p<0.001), with the overall mean for the protocol lowered to 11.7±0.9 au for caffeine compared to 12.8±1.3 au. Caffeine supplementation with a carbohydrate feeding strategy failed to affect metabolic and metabolite responses, although reductions in perception of exercise were observed. While a 12.8% increase in exercise capacity was noted the findings were not significant, possibly due to the small sample size.

Which are the Nutritional Supplements Used by Beach-Volleyball Athletes? A Cross-Sectional Study at the Italian National Championship

Beach volleyball is an intermittent team sport played under high temperature and humidity. Given that some nutritional supplements can enhance sports performance, this study aimed to evaluate the quantity and the heterogeneity of the nutritional supplementation practices of amateur (n = 69) and professional (n = 19) beach volley athletes competing in the Italian National Championship; an online form was used to collect data about the supplementation habits. The latent class analysis was used to find sub-groups characterised by different habits regarding supplements consumption. The most frequently used supplements (more than once a week) are vitamins B and C (39.2% of athletes), protein (46.8%), and caffeine (36.9%). The latent class analysis revealed three different sub-groups of athletes: the first class (56.7%) included athletes who were used to take very few supplements, the second class (17.0%) was characterised by higher consumption of supplements and the third class (26.2%) was in the middle between the others two. Groups were characterised not only by the quantity but also by the category of supplements used. Our results highlighted a high heterogeneity in supplementation habits. A pragmatic approach to supplements and sports foods is needed in the face of the evidence that some products can usefully contribute to enhancing performance.

Assessment of Dietary Under-Reporting in Italian College Team Sport Athletes

BACKGROUND

Nutrition is an important factor for sports performance and the assessment of dietary intakes in athletes can correct unhealthy eating habits. However, dietary assessment may be biased due to misreporting. The aim of our study was to investigate the occurrence of misreporting in a sample of collegiate team sport athletes.

METHODS

A total of 50 athletes participated. Each athlete filled in food records for seven days. Reported energy intake (EI) was considered in relation to the predicted basal metabolic rate (BMR) and expressed as the ratio EI/ BMR. All participants with EI/BMRestd ≤1.23 were classified as "low energy reporters" (LER), and those with an EI/BMRestd ratio >1.23 were classified as "adequate energy reporters" (AER).

RESULTS

According to cut-off values for under-reporting, 28 out of 50 athletes (56%) were classified as LER. The LER (16 M/12 F) had significantly higher BMI (23.17 ± 3.46 kg/m2 compared to 21.41 ± 1.91 kg/m2; p = 0.038) than the AER. The EI/kg fat free mass (FFM) was significantly lower in LER than the AER (33.34 ± 6.56 kcal/FFM compared to 48.51 ± 8.59 kcal/FFM, p < 0.0001). Nutrient intake was also significantly different between the two groups.

CONCLUSIONS

Our results suggest that under-reporting of energy intake by collegiate team sport athletes may occur frequently and needs to be taken into consideration in the interpretation of nutrient intake.

Effects of Creatine Supplementation on Athletic Performance in Soccer Players: A Systematic Review and Meta-Analysis

Studies have shown that creatine supplementation increases intramuscular creatine concentrations, favoring the energy system of phosphagens, which may help explain the observed improvements in high-intensity exercise performance. However, research on physical performance in soccer has shown controversial results, in part because the energy system used is not taken into account. The main aim of this investigation was to perform a systematic review and meta-analysis to determine the efficacy of creatine supplementation for increasing performance in skills related to soccer depending upon the type of metabolism used (aerobic, phosphagen, and anaerobic metabolism). A structured search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the Medline/PubMed and Web of Science, Cochrane Library, and Scopus databases until January 2019. The search included studies with a double-blind and randomized experimental design in which creatine supplementation was compared to an identical placebo situation (dose, duration, timing, and drug appearance). There were no filters applied to the soccer players' level, gender, or age. A final meta-analysis was performed using the random effects model and pooled standardized mean differences (SMD) (Hedges's g). Nine studies published were included in the meta-analysis. This revealed that creatine supplementation did not present beneficial effects on aerobic performance tests (SMD, -0.05; 95% confidence interval (CI), -0.37 to 0.28; p = 0.78) and phosphagen metabolism performance tests (strength, single jump, single sprint, and agility tests: SMD, 0.21; 95% CI, -0.03 to 0.45; p = 0.08). However, creatine supplementation showed beneficial effects on anaerobic performance tests (SMD, 1.23; 95% CI, 0.55⁻1.91; p <0.001). Concretely, creatine demonstrated a large and significant effect on Wingate test performance (SMD, 2.26; 95% CI, 1.40⁻3.11; p <0.001). In conclusion, creatine supplementation with a loading dose of 20⁻30 g/day, divided 3⁻4 times per day, ingested for 6 to 7 days, and followed by 5 g/day for 9 weeks or with a low dose of 3 mg/kg/day for 14 days presents positive effects on improving physical performance tests related to anaerobic metabolism, especially anaerobic power, in soccer players.

Partial Replacement of Maltodextrin by Sweet Potato Flour (Ipomoea Batatas L. Lamarck) in the Development of a Shake Beverage

Sweet potato flour contains low-glycemic complex carbohydrates and, when it is ingested, prevents insulin spikes and prolongs the feeling of satiety. The aim of this study was to elaborate and to verify the acceptability of the shake with the total or partial substitution of maltodextrin for sweet potato flour. To elaborate the shake beverage, we used a 22 factorial design, with three central points, thus generating seven formulations. For the taste, color, texture, appearance, acceptance and attitude of purchase properties, sensory tests were conducted using a nine-point hedonic scale and panelists (n = 50). The highest acceptability formulations, formulations 3 (10% sweet potato flour; 25% maltodextrin) and 7 (0% sweet potato flour; 25% maltodextrin), were submitted to pH, moisture, ash, protein, lipid, crude fiber and total carbohydrate analyses. The statistical difference between the formulations from the T test (p < 0.05) was verified for the moisture, ash and lipid parameters. Formulation 3 presented higher values of moisture (93.26 ± 0.57) and lipids (1.91 ± 0.01), and formulation 7 had higher values of ash (0.39 ± 0.01). The results of the sensorial and physicochemical analyses of the shake indicate that sweet potato flour shows potential for the elaboration of this drink.

Muscle Glycogen Utilization During an Australian Rules Football Game

PURPOSE

To better understand the carbohydrate (CHO) requirement of Australian Football (AF) match play by quantifying muscle glycogen utilization during an in-season AF match.

METHODS

After a 24-h CHO-loading protocol of 8 and 2 g/kg in the prematch meal, 2 elite male forward players had biopsies sampled from m. vastus lateralis before and after participation in a South Australian Football League game. Player A (87.2 kg) consumed water only during match play, whereas player B (87.6 kg) consumed 88 g CHO via CHO gels. External load was quantified using global positioning system technology.

RESULTS

Player A completed more minutes on the ground (115 vs 98 min) and covered greater total distance (12.2 vs 11.2 km) than player B, although with similar high-speed running (837 vs 1070 m) and sprinting (135 vs 138 m). Muscle glycogen decreased by 66% in player A (pre: 656 mmol/kg dry weight [dw], post: 223 mmol/kg dw) and 24% in player B (pre: 544 mmol/kg dw, post: 416 mmol/kg dw).

CONCLUSION

Prematch CHO loading elevated muscle glycogen concentrations (ie, >500 mmol/kg dw), the magnitude of which appears sufficient to meet the metabolic demands of elite AF match play. The glycogen cost of AF match play may be greater than in soccer and rugby, and CHO feeding may also spare muscle glycogen use. Further studies using larger sample sizes are now required to quantify the interindividual variability of glycogen cost of match play (including muscle and fiber-type-specific responses), as well examining potential metabolic and ergogenic effects of CHO feeding.

Nutritional Intake in Australian Football Players: Sports Nutrition Knowledge and Macronutrient and Micronutrient Intake

This study compared the energy, macronutrient, and micronutrient intake in elite and sub-elite Australian football players and compared nutritional intake to current recommendations. Sports nutrition knowledge was also quantified and compared between elite and sub-elite players. Nutritional intake was quantified in elite (n = 35) and sub-elite (n = 31) players using the Automated Self-Administered 24-Hour Dietary Assessment Tool. The 88-item Sports Nutrition Knowledge Questionnaire was used to quantify knowledge related to general nutrition concepts, fluid, recovery, weight control, and supplements. Elite players had a higher nutritional intake (mean ± SD) for energy (14,140 ± 5,887 kJ [elite players] vs 10,412 ± 3,316 kJ [sub-elite players]; P = .002) and fat (40% ± 6% [elite players] vs 34% ± 6% [sub-elite players]; P < .001). Protein intake exceeded the recommended intake in 77% of elite players and 68% of sub-elite players, and carbohydrate intake was below the recommended intake for 91% of elite players and 97% of sub-elite players. Sodium intake recommendations were exceeded by 100% of elite and sub-elite players. Both elite and sub-elite players answered 51% of the Sports Nutrition Knowledge Questionnaire questions correctly. The percentage of correctly answered questions specific to supplements was 27% for elite players and 18% for sub-elite players. The results of the current investigation suggest that Australian football players' nutritional intake is inconsistent with current recommendations for macronutrients and some micronutrients. Furthermore, players may benefit from additional knowledge of the risks and benefits of supplement use.

Dietetic-nutritional, physical and physiological recovery methods post-competition in team sports

To a proper recovery, is absolutely necessary to know that athletes with enhanced recovery after maximal exercise are likely to perform better in sports. Recovery strategies are commonly used in team sports despite limited scientific evidence to support their effectiveness in facilitating optimal recovery and the players spend a much greater proportion of their time recovering than they do in training. According to authors, some studies investigated the effect of recovery strategies on physical performance in team sports, lack of experimental studies about the real origin of the fatigue, certify the need for further study this phenomenon. Thus, developing effective methods for helping athletes to recover is deemed essential. Therefore, the aim of this review is provide information for his practical application, based on scientific evidence about recovery in team sports.

Effects of beetroot juice supplementation on intermittent high-intensity exercise efforts

Beetroot juice contains high levels of inorganic nitrate (NO3-) and its intake has proved effective at increasing blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of investigations have sought to assess the effects of this supplement on performance at high-intensity exercise. Here we review the few studies that have addressed this issue. The databases Dialnet, Elsevier, Medline, Pubmed and Web of Science were searched for articles in English, Portuguese and Spanish published from 2010 to March 31 to 2017 using the keywords: beet or beetroot or nitrate or nitrite and supplement or supplementation or nutrition or "sport nutrition" and exercise or sport or "physical activity" or effort or athlete. Nine articles fulfilling the inclusion criteria were identified. Results indicate that beetroot juice given as a single dose or over a few days may improve performance at intermittent, high-intensity efforts with short rest periods. The improvements observed were attributed to faster phosphocreatine resynthesis which could delay its depletion during repetitive exercise efforts. In addition, beetroot juice supplementation could improve muscle power output via a mechanism involving a faster muscle shortening velocity. The findings of some studies also suggested improved indicators of muscular fatigue, though the mechanism involved in this effect remains unclear.

Quantification of training load, energy intake, and physiological adaptations during a rugby preseason: a case study from an elite European rugby union squad

Rugby Union (RU) is a high-speed collision sport consisting of an intermittent activity profile. Given the extreme physical demands of the sport, significant emphasis is placed on players possessing high lean body mass while minimizing body fat. Anecdotally, the most significant changes in body composition are observed during the preseason; however, there are no objective data on the physiological demands and energy intake during this time. We therefore monitored 45 elite European RU players over the 10-week preseason period by assessing training load using Global Positioning System and session rate of perceived exertion (sRPE) while also assessing changes in anthropometry and physical performance. For forwards and backs, respectively, mean weekly distance covered was 9,774 m (1,404) and 11,585 m (1,810) with a total mean weekly sRPE of 3,398 (335) arbitrary units and 2,944 (410) arbitrary units. Mean daily energy intake was 14.8 MJ (1.9) and 13.3 MJ (1.9), carbohydrate (CHO) intake was 3.3 (0.7) and 4.14 (0.4) g·kg body mass, protein intake was 2.52 (0.3) and 2.59 (0.6) g·kg body mass, and fat intake was 1.0 (0.3) and 0.95 (0.3) g·kg body mass for forwards and backs, respectively. Markers of physical performance (1 repetition maximum strength, speed, and repeated sprint tests) and anthropometry (body fat and estimated lean mass) improved in all players. Interestingly, all players self-selected a "low" CHO "high" protein diet. Based on physiological improvements the training load and energy intake seems appropriate, although further research is required to evaluate if such energy intakes would also be suitable for match day performance.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game seems to have the greatest impact on intermittent sports performance towards the end of the game.

Physiological and health-related adaptations to low-volume interval training: influences of nutrition and sex

Interval training refers to the basic concept of alternating periods of relatively intense exercise with periods of lower-intensity effort or complete rest for recovery. Low-volume interval training refers to sessions that involve a relatively small total amount of exercise (i.e. ≤10 min of intense exercise), compared with traditional moderate-intensity continuous training (MICT) protocols that are generally reflected in public health guidelines. In an effort to standardize terminology, a classification scheme was recently proposed in which the term 'high-intensity interval training' (HIIT) be used to describe protocols in which the training stimulus is 'near maximal' or the target intensity is between 80 and 100 % of maximal heart rate, and 'sprint interval training' (SIT) be used for protocols that involve 'all out' or 'supramaximal' efforts, in which target intensities correspond to workloads greater than what is required to elicit 100 % of maximal oxygen uptake (VO2max). Both low-volume SIT and HIIT constitute relatively time-efficient training strategies to rapidly enhance the capacity for aerobic energy metabolism and elicit physiological remodeling that resembles changes normally associated with high-volume MICT. Short-term SIT and HIIT protocols have also been shown to improve health-related indices, including cardiorespiratory fitness and markers of glycemic control in both healthy individuals and those at risk for, or afflicted by, cardiometabolic diseases. Recent evidence from a limited number of studies has highlighted potential sex-based differences in the adaptive response to SIT in particular. It has also been suggested that specific nutritional interventions, in particular those that can augment muscle buffering capacity, such as sodium bicarbonate, may enhance the adaptive response to low-volume interval training.

Recovery interventions and strategies for improved tennis performance

Improving the recovery capabilities of the tennis athlete is receiving more emphasis in the research communities, and also by practitioners (coaches, physical trainers, tennis performance specialists, physical therapists, etc). The purpose of this article was to review areas of recovery to limit the severity of fatigue and/or speed recovery from fatigue. This review will cover four broad recovery techniques commonly used in tennis with the belief that the interventions may improve athlete recovery and therefore improve adaptation and future performance. The four areas covered are: (1) temperature-based interventions, (2) compressive clothing, (3) electronic interventions and (4) nutritional interventions.

Sports nutrition needs: before, during, and after exercise

This article discusses how athletes should properly fuel their bodies before, during, and after exercise to maximize athletic performance. Emphasis is placed on hydration status and glycogen stores being maintained above deficits that negatively affect sport performance. Timing of nutrient intake is as important as composition.

Sport-specific nutrition: practical strategies for team sports

Implementation of a nutrition programme for team sports involves application of scientific research together with the social skills necessary to work with a sports medicine and coaching staff. Both field and court team sports are characterized by intermittent activity requiring a heavy reliance on dietary carbohydrate sources to maintain and replenish glycogen. Energy and substrate demands are high during pre-season training and matches, and moderate during training in the competitive season. Dietary planning must include enough carbohydrate on a moderate energy budget, while also meeting protein needs. Strength and power team sports require muscle-building programmes that must be accompanied by adequate nutrition, and simple anthropometric measurements can help the nutrition practitioner monitor and assess body composition periodically. Use of a body mass scale and a urine specific gravity refractometer can help identify athletes prone to dehydration. Sports beverages and caffeine are the most common supplements, while opinion on the practical effectiveness of creatine is divided. Late-maturing adolescent athletes become concerned about gaining size and muscle, and assessment of maturity status can be carried out with anthropometric procedures. An overriding consideration is that an individual approach is needed to meet each athlete's nutritional needs.