Efeitos da suplementação de cafeína na performance do endurance: uma revisão do esporte / Effects of caffeine supplementation on endurance performance: a sport review

Caffeine is a food supplement widely consumed by athletes, but it has not been established. So far, the veracity of their labeling in terms of the dosage and cause/effect relationship aimed at the consumer. The aim is to analyze the health claims and the dosage presented on the labeling of caffeine supplements and to evaluate if they follow the European Food Safety Authority (EFSA) and international criteria. A descriptive cross-sectional study of a sample of caffeine supplements was carried out. The search was done through the Amazon and Google Shopping web portals. In order to assess the adequacy of the health claims, the guidelines of reference established by European Food Safety Authority were compared to the Academy of Nutrition and Dietetics, International Olympic Committee, and Australian Institute of Sport guidelines; in addition, recent systematic reviews were addressed. A review of labels of 42 caffeine supplements showed that, in less than 3% of the products were the health claims supported by the recommendations and by the labeled quantity of caffeine. The claims that fully complied the recommendations were, “improves or increases endurance performance”, “improves strength performance”, or “improves short-term performance”. In most cases, the recommended dosage was 200 mg/day for these products, which is the minimum for the caffeine effects to be declared. The rest of the health claims were not adequate or need to be modified. Most of the health claims identified indicated an unproven cause and effect, which constitutes consumer fraud, and so must be modified or eliminated.

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Vector field path following of a full-wing solar-powered Unmanned Aerial Vehicle (UAV) landing based on Dubins path: a lesson from multiple landing failures

The Aeronautical Journal ◽

10.1017/aer.2021.26 ◽

2021 ◽

pp. 1-30

Author(s):

A. Guo ◽

Z. Zhou ◽

R. Wang ◽

X. Zhao ◽

X. Zhu

Keyword(s):

Vector Field ◽

Path Following ◽

Endurance Performance ◽

Electrical Energy ◽

Lateral Control ◽

Special Configuration ◽

Straight Line ◽

Lateral Distance ◽

Solar Powered ◽

Line Path

Abstract The full-wing solar-powered UAV has a large aspect ratio, special configuration, and excellent aerodynamic performance. This UAV converts solar energy into electrical energy for level flight and storage to improve endurance performance. The UAV only uses a differential throttle for lateral control, and the insufficient control capability during crosswind landing results in a large lateral distance bias and leads to multiple landing failures. This paper analyzes 11 landing failures and finds that a large lateral distance bias at the beginning of the approach and the coupling of base and differential throttle control is the main reason for multiple landing failures. To improve the landing performance, a heading angle-based vector field (VF) method is applied to the straight-line and orbit paths following and two novel 3D Dubins landing paths are proposed to reduce the initial lateral control bias. The results show that the straight-line path simulation exhibits similar phenomenon with the practical failure; the single helical path has the highest lateral control accuracy; the left-arc to left-arc (L-L) path avoids the saturation of the differential throttle; and both paths effectively improve the probability of successful landing.

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Monitoring Training and Recovery during a Period of Increased Intensity or Volume in Recreational Endurance Athletes

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18052401 ◽

2021 ◽

Vol 18 (5) ◽

pp. 2401

Author(s):

Olli-Pekka Nuuttila ◽

Ari Nummela ◽

Keijo Häkkinen ◽

Santtu Seipäjärvi ◽

Heikki Kyröläinen

Keyword(s):

Heart Rate ◽

Control Period ◽

Endurance Performance ◽

Training Period ◽

Training Intensity ◽

Countermovement Jump ◽

Maximal Speed ◽

Individualized Approach ◽

Monitoring Training

The purpose of the study was to examine the effects of progressively increased training intensity or volume on the nocturnal heart rate (HR) and heart rate variability (HRV), countermovement jump, perceived recovery, and heart rate-running speed index (HR-RS index). Another aim was to analyze how observed patterns during the training period in these monitoring variables were associated with the changes in endurance performance. Thirty recreationally trained participants performed a 10-week control period of regular training and a 10-week training period of either increased training intensity (INT, n = 13) or volume (VOL, n = 17). Changes in endurance performance were assessed by an incremental treadmill test. Both groups improved their maximal speed on the treadmill (INT 3.4 ± 3.2%, p < 0.001; VOL 2.1 ± 1.8%, p = 0.006). In the monitoring variables, only between-group difference (p = 0.013) was found in nocturnal HR, which decreased in INT (p = 0.016). In addition, perceived recovery decreased in VOL (p = 0.021) and tended to decrease in INT (p = 0.056). When all participants were divided into low-responders and responders in maximal running performance, the increase in the HR-RS index at the end of the training period was greater in responders (p = 0.005). In conclusion, current training periods of increased intensity or volume improved endurance performance to a similar extent. Countermovement jump and HRV remained unaffected, despite a slight decrease in perceived recovery. Long-term monitoring of the HR-RS index may help to predict positive adaptations, while interpretation of other recovery-related markers may need a more individualized approach.

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Efficacy of Popular Diets Applied by Endurance Athletes on Sports Performance: Beneficial or Detrimental? A Narrative Review

Nutrients ◽

10.3390/nu13020491 ◽

2021 ◽

Vol 13 (2) ◽

pp. 491

Author(s):

Aslı Devrim-Lanpir ◽

Lee Hill ◽

Beat Knechtle

Keyword(s):

Gastrointestinal Symptoms ◽

Endurance Performance ◽

Endurance Athletes ◽

Intermittent Fasting ◽

Nutritional Strategy ◽

Current Perspective ◽

Vegetarian Diets ◽

Fat Diets ◽

The Impact ◽

Harsh Conditions

Endurance athletes need a regular and well-detailed nutrition program in order to fill their energy stores before training/racing, to provide nutritional support that will allow them to endure the harsh conditions during training/race, and to provide effective recovery after training/racing. Since exercise-related gastrointestinal symptoms can significantly affect performance, they also need to develop strategies to address these issues. All these factors force endurance athletes to constantly seek a better nutritional strategy. Therefore, several new dietary approaches have gained interest among endurance athletes in recent decades. This review provides a current perspective to five popular diet approaches: (a) vegetarian diets, (b) high-fat diets, (c) intermittent fasting diets, (d) gluten-free diet, and (e) low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diets. We reviewed scientific studies published from 1983 to January 2021 investigating the impact of these popular diets on the endurance performance and health aspects of endurance athletes. We also discuss all the beneficial and harmful aspects of these diets, and offer key suggestions for endurance athletes to consider when following these diets.

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Electrically-induced quadriceps fatigue in the contralateral leg impairs ipsilateral knee extensors performance

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00363.2020 ◽

2021 ◽

Author(s):

Fabio Giuseppe Laginestra ◽

Markus Amann ◽

Emine Kirmizi ◽

Gaia Giuriato ◽

Chiara Barbi ◽

...

Keyword(s):

Muscle Activation ◽

Central Fatigue ◽

Endurance Performance ◽

Voluntary Exercise ◽

Peripheral Fatigue ◽

Knee Extensors ◽

Motor Drive ◽

Time To Exhaustion ◽

Crossover Effect ◽

The Impact

Muscle fatigue induced by voluntary exercise, which requires central motor drive, causes central fatigue that impairs endurance performance of a different, non-fatigued muscle. This study investigated the impact of quadriceps fatigue induced by electrically-induced (no central motor drive) contractions on single-leg knee-extension (KE) performance of the subsequently exercising ipsilateral quadriceps. On two separate occasions, eight males completed constant-load (85% of maximal power-output) KE exercise to exhaustion. In a counterbalanced manner, subjects performed the KE exercise with no pre-existing quadriceps fatigue in the contralateral leg on one day (No-PreF), while on the other day, the same KE exercise was repeated following electrically-induced quadriceps fatigue in the contralateral leg (PreF). Quadriceps fatigue was assessed by evaluating pre- to post-exercise changes in potentiated twitch force (ΔQtw,pot; peripheral-fatigue), and voluntary muscle activation (ΔVA; central-fatigue). As reflected by the 57±11% reduction in electrically-evoked pulse force, the electrically-induced fatigue protocol caused significant knee-extensors fatigue. KE endurance time to exhaustion was shorter during PreF compared to No-PreF (4.6±1.2 vs 7.7±2.4 min; p<0.01). While ΔQtw,pot was significantly larger in No-PreF compared to PreF (-60% vs -52%, p<0.05), ΔVA was greater in PreF (-14% vs -10%, p<0.05). Taken together, electrically-induced quadriceps fatigue in the contralateral leg limits KE endurance performance and the development of peripheral fatigue in the ipsilateral leg. These findings support the hypothesis that the crossover-effect of central fatigue is mainly mediated by group III/IV muscle afferent feedback and suggest that impairments associated with central motor drive may only play a minor role in this phenomenon.

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Liver-Metabolizing Genes and Their Relationship to the Performance of Elite Spanish Male Endurance Athletes; a Prospective Transversal Study

Sports Medicine - Open ◽

10.1186/s40798-019-0227-7 ◽

2019 ◽

Vol 5 (1) ◽

Cited By ~ 1

Author(s):

David Varillas Delgado ◽

Juan José Tellería Orriols ◽

Carlos Martín Saborido

Keyword(s):

Binary Logistic Regression ◽

Endurance Performance ◽

Endurance Athletes ◽

Genetic Profile ◽

Glutathione S Transferase ◽

Binary Logistic Regression Model ◽

Genotypic Distribution ◽

Endurance Runner ◽

Cytochrome P450 Family ◽

First Time

Abstract Background The genetic profile that is needed to define an endurance athlete has been studied during recent years. The main objective of this work is to approach for the first time the study of genetic variants in liver-metabolizing genes and their role in endurance performance by comparing the allelic and genotypic frequencies in elite endurance athletes to the non-athlete population. Methods Genotypic and allelic frequencies were determined in 123 elite endurance athletes (75 professional road cyclists and 48 endurance elite runners) and 122 male non-athlete subjects (sedentary). Genotyping of cytochrome P450 family 2 subfamily D member 6 (CYP2D6 rs3892097), glutathione-S transferase mu isoform 1 (GSTM1), glutathione S-transferase pi (GSTP rs1695) and glutathione S-transferase theta (GSTT) genes was performed by polymerase chain reaction (PCR). The combination of the polymorphisms for the “optimal” polygenic profile has been quantified using the genotype score (GS). Results Statistical differences were found in the genetic distributions between elite endurance athletes and non-athletes in CYP2D6 (p < 0.001) and GSTT (p = 0.014) genes. The binary logistic regression model showed a favourable OR (odds ratio) of being an elite endurance runner against a professional road cyclist (OR: 2.403, 95% CI: 1.213–4.760 (p = 0.002)) in the polymorphisms studied. Conclusions Genotypic distribution of liver-metabolizing genes in elite endurance athletes is different to non-athlete subjects, with a favourable gene profile in elite endurance athletes in terms of detoxification capacity.

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