Effects of Acute Ingestion of Guarana (Paullinia Cupana) on Soccer Player Performance: A Randomized, Cross-over, Placebo-Controlled Study.

OBJECTIVE: To investigate the acute effects of ingesting a beverage containing guarana (Paullinia cupana) seed powder on performance during field tests related to physical capacities that are determinants of soccer performance, such as lower limb power, sprint, agility, and the capacity to carry out intermittent exercise. METHODS: The study was conducted using a randomized, crossover, and counterbalanced design, with a beverage containing guarana or placebo administered in a double-blind manner. Twenty-seven under-17 soccer players of a professional soccer club performed a battery of tests 60 min after the ingestion of guarana (3 g of the fruit seed powder) or placebo. Trials were performed with a 7-day washout period. The battery of tests included a countermovement jump test, sprints of 10 and 20 m, an Illinois agility test, and a Yo-Yo Intermittent Recovery Test level 1 (YYIR1). RESULTS: Guarana ingestion did not improve countermovement jump, sprints, or agility (p > 0.05). However, guarana ingestion increased the distance covered in the YYIR1, compared with placebo ingestion (p = 0.01). CONCLUSION: Acute ingestion of guarana improves the capacity to perform intermittent exercise in soccer players but seems to be ineffective to improve lower limb power, sprint, and agility.

Variations in strength-speed-power performance across the season: do true changes occur in elite rugby players?

This study aimed to determine, through the use of a highly sensitive statistical tool, whether real changes in performance were present; and compare the rates of meaningful variations in strength, speed, and power parameters at different time-points during the competitive season in national team rugby players. Thirty-two players were assessed 5 times across the season using the following tests: squat jump and countermovement jump tests; 30-m sprint velocity; and one-repetition maximum (1RM) in the half-squat and bench-press exercises. A repeated-measures analysis of variance was conducted to test for differences between successive time-points. Individual coefficients of variation values were used to set target scores for post-measurements and examine whether changes in performance parameters were greater than the natural test variance, thus providing an indication of whether "true changes" occurred. No significant changes were detected in the vertical jump height, 1RM measures, and sprint velocity and momentum throughout the 11-month period (P > 0.05). True changes occurred much more frequently for strength-power measures than for sprint velocity and momentum. Elite rugby union players did not exhibit significant variations in neuromuscular performance across the competitive period, when a group-based analysis was conducted. However, at the individual level, "true changes" in strength-power-(but not in speed-) related qualities were consistently observed over the competitive season.

Identifying pesticides of high concern for ecosystem, plant, animal, and human health: A comprehensive field study across Europe and Argentina.

The widespread and excessive use of pesticides in modern agricultural practices has caused pesticide contamination of the environment, animals, and humans, with confirmed serious health consequences. This study aimed to identify the 20 most critical substances based on an analysis of detection frequency (DF) and median concentrations (MC) across environmental and biological matrices. A sampling campaign was conducted across 10 case study sites in Europe and 1 in Argentina, each encompassing conventional and organic farming systems. We analysed 209 active substances in a total of 4609 samples. All substances ranked among the 20 most critical were detected in silicon wristbands worn by humans and animals and indoor dust from both farming systems. Five of them were detected in all environmental matrices. Overall, higher values of DF and MC, including in the blood plasma of animals and humans, were recorded in samples of conventional compared to organic farms. The differences between farming systems were greater in the environmental samples and less in animal and human samples. Ten substances were detected in animal blood plasma from conventional farms and eight in animal blood plasma from organic farms. Two of those, detected in both farming systems, are classified as hazardous for mammals (acute). Five substances detected in animal blood plasma from organic farms and seven detected in animal blood plasma from conventional farms are classified as hazardous for mammals (dietary). Three substances detected in human blood plasma are classified as carcinogens. Seven of the substances detected in human blood plasma are classified as endocrine disruptors. Six substances, of which five were detected in human blood plasma, are hazardous for reproduction/development. Efforts are needed to elucidate the unknown effects of mixtures, and it is crucial that such research also considers biocides and banned substances, which constitute a baseline of contamination that adds to the effect of substances used in agriculture.

Effects of Different Conditioning Activities on the Sprint Performance of Elite Sprinters: A Systematic Review With Meta-Analysis.

PURPOSE: Postactivation performance enhancement (PAPE), which refers to the phenomena associated with the attainment of enhanced performance in sport-specific tasks after a conditioning activity, is an important objective of warming-up practices in many sports. This is even more relevant for sprinters, as potential increases in sprinting speed will directly influence their competitive results. This systematic review with meta-analysis evaluated the effects of different PAPE protocols (ie, using plyometrics, strength-power exercises, and resisted/assisted sprints) on the sprinting performance (ie, sprint time or sprint speed) of competitive sprinters. METHODS: Initially, 1205 records published until last December 18 were identified, using the following databases: PubMed/MEDLINE, Scopus, and Clarivate Web of Science. After removing duplicates and screening titles and abstracts, 14 high-quality studies met the inclusion criteria for the meta-analysis. RESULTS: Overall, there were no significant changes in sprint performance after implementing various types of conditioning activities (standardized mean difference [SMD] = 0.16 [95% CI, -0.02 to 0.33]; Z = 1.78; P = .08; I2 = 0%). In addition, when comparing prechanges and postchanges between experimental, control, and other conditions, no significant differences were found in sprint speed or time across all studies (SMD = 0.09 [95% CI, -0.10 to 0.28]; Z = 0.92; P = .36; I = 0%). CONCLUSIONS: Results revealed that different types of conditioning activities may not be capable of acutely enhancing the sprint speed of competitive sprinters. This aligns with previous observations indicating that sprinting is a highly stable physical capacity, a phenomenon that is even more consistent among elite sprinters. Coaches and sport scientists should collaborate to develop more efficient PAPE protocols for these highly specialized athletes, with special attention to study design and individualization, while considering their effects on acceleration versus top speed.

Jump Squats Performed with Both Light and Heavy Loads Have Similar Effects on the Physical Performance of Elite Rugby Players during the Initial Phase of the Competitive Period.

We examined the effectiveness of two different jump-squat (JS) loading ranges on the physical performance of rugby players. Twenty-eight elite male rugby players were divided into two JS training groups: a light-load JS group ("LJS"; JS at 40% of the one-repetition maximum [1RM] in the half-squat (HS) exercise) and a heavy-load JS group ("HJS"; JS at 80% HS-1RM). Players completed the distinct training programs over four weeks, three times per week, during the initial phase of the competitive period. Pre- and post-training tests were conducted in the following sequence: vertical jumps, a 30-m speed test, peak power in the JS and the HS, and maximum isometric force in the HS. Additionally, the rating of perceived exertion (RPE) was assessed at the end of all training sessions throughout the intervention. A two-way ANOVA with repeated measures, followed by the Tukey's post-hoc test, was employed to analyze differences between groups. The level of significance was set at p < 0.05. Effect sizes were used to assess the magnitude of differences between pre- and post-training data. Except for the RPE values (which were lower in the LJS group), no significant changes were detected for any other variable. In summary, using either a light- (40% HS-1RM) or a heavy-load (80% HS-1RM) JS during the initial phase of the competitive period is equally effective in maintaining physical performance levels attained during the preceding training period (pre-season), with the significant advantage of the light-load protocol resulting in lower levels of the RPE. This finding may have important implications for resistance training programming, especially in disciplines where acute and chronic fatigue is always a problematic issue.

Effectiveness of short sprint interval training in women with major depressive disorder: a proof-of-concept study.

Background: High-intensity intermittent training has emerged as an option for treating major depressive disorder (MDD). However, short sprint training (sSIT), an efficient HIIT modality, has not been tested yet for this purpose. The sSIT has been proven to induce the same metabolic adaptations, with the advantage of promoting lower muscle fatigue than other HIIT protocols. Methods: Seventeen adult women diagnosed with moderate/severe MDD were randomly allocated into a sSIT group (n=9) or a control condition (n=8). The sSIT group completed, over two weeks, six 6-10-min sessions which consisted of 3-12 "all out" sprints of 5 s interspersed with low-intensity recovery of 30-45 s. The week before and after the intervention, both groups were evaluated with the Hamilton Depression Rating Scale of 21-itens (HAM-D21), and for physical fitness and incidental physical activity. Results: The sSIT group exhibited significant improvements for HAM-D21 scores (24.6±8.2 vs. 16.8±10.1), maximum aerobic power (140±15 vs. 155±15 W), countermovement jump (13.0±3.4 vs. 14.9±3.1 cm), % of body fatness (32.4±4.4 vs. 29.3±3.8%), and 4-days number of steps (13,626±11,309 vs. 16,643±15,371) after the training period when compared to the control group. Conclusion: Less than 1 hour of a sSIT protocol over two weeks have demonstrated to reduce depressive symptoms, while improving aerobic fitness and body composition, and increasing incidental physical activity in a sample of women diagnosed with MDD.

Sprint and Anaerobic Power with the Soccer-Specific ACTN3 Gene: A Distintive Example / Sprint y Potencia Anaeróbica con el Gen ACTN3 Específico del Fútbol: Un Ejemplo Distintivo

SUMMARY: The aim of this study is twofold: (1) to identify differences in certain anaerobic parameters (10m sprint, 30m sprint, anaerobic power, and Illinois agility tests) between professional and amateur soccer players, and (2) to determine whether there is a difference in the ACTN3 gene polymorphism between professional and amateur soccer players. Ultimately, the goal is to reveal which parameters contribute to the differentiation in these two aspects. A total of 133 volunteer soccer players, including 71 professionals and 62 amateurs, participated in the research. DNA extraction from buccal epithelial cells was performed using a commercial kit to determine the genetic background of the athletes, and Real-Time PCR was conducted for genotyping. Statistical analysis of the findings obtained from the test results was performed using the SPSS 23 (SPSS Inc., Chicago, IL, USA) package program. The homogeneity of variance of the data was assessed using the Levene Test, and normal distribution analyses were conducted using the Shapiro-Wilk Test. Chi-square and Mann-Whitney U tests were employed for parameter analysis. The significance level was set at p0.05). However, there is a statistically significant difference in anaerobic parameters (10m sprint, 30m sprint, and anaerobic power) except for the Illinois test (p<0.05). In conclusion, our study found that gene polymorphism is not a differentiating factor between professional and amateur soccer players, but speed (10m and 30m) and anaerobic power parameters are differentiating factors.

Los objetivos de este estudio fueron: 1º identificar diferencias en ciertos parámetros anaeróbicos (sprint de 10 m, sprint de 30 m, potencia anaeróbica y pruebas de agilidad de Illinois) entre jugadores de fútbol profesionales y amateurs, y 2º determinar si existe una diferencia en el polimorfismo del gen ACTN3 entre jugadores de fútbol profesionales y aficionados. En definitiva, el objetivo fue revelar qué parámetros contribuyen a la diferenciación en estos dos aspectos. En la investigación participaron un total de 133 jugadores de fútbol voluntarios, incluidos 71 profesionales y 62 aficionados. La extracción de ADN de las células epiteliales orales se realizó utilizando un kit comercial para determinar los antecedentes genéticos de los atletas y se realizó una PCR en tiempo real para el genotipado. El análisis estadístico de los hallazgos obtenidos a partir de los resultados de las pruebas se realizó utilizando el programa de paquete SPSS 23 (SPSS Inc., Chicago, IL, EE. UU.). La homogeneidad de la varianza de los datos se evaluó mediante la prueba de Levene y los análisis de distribución normal se realizaron mediante la prueba de Shapiro-Wilk. Para el análisis de parámetros se emplearon las pruebas de Chi-cuadrado y U de Mann-Whitney. El nivel de significancia se fijó en p0,05). Sin embargo, existe una diferencia estadísticamente significativa en los parámetros anaeróbicos (sprint de 10 m, sprint de 30 m y potencia anaeróbica) excepto para la prueba de Illinois (p<0,05). En conclusión, nuestro estudio encontró que el polimorfismo genético no es un fac- tor diferenciador entre jugadores de fútbol profesionales y amateurs, pero sí los parámetros de velocidad (10 m y 30 m) y potencia anaeróbica.

Assessing pesticide residues occurrence and risks in water systems: A Pan-European and Argentina perspective.

Freshwater ecosystems face a particularly high risk of biodiversity loss compared to marine and terrestrial systems. The use of pesticides in agricultural fields is recognized as a relevant stressor for freshwater environments, exerting a negative impact worldwide on the overall status and health of the freshwater communities. In the present work, part of the Horizon 2020 funded SPRINT project, the occurrence of 193 pesticide residues was investigated in 64 small water bodies of distinct typology (creeks, streams, channels, ditches, rivers, lakes, ponds and reservoirs), located in regions with high agricultural activity in 10 European countries and in Argentina. Mixtures of pesticide residues were detected in all water bodies (20, median; 8-40 min-max). Total pesticide levels found ranged between 6.89 and 5860 ng/L, highlighting herbicides as the dominant type of pesticides. Glyphosate was the compound with the highest median concentration followed by 2,4-D and MCPA, and in a lower degree by dimethomorph, fluopicolide, prothioconazole and metolachlor(-S). Argentina was the site with the highest total pesticide concentration in water bodies followed by The Netherlands, Portugal and France. One or more pesticides exceeded the threshold values established in the European Water Framework Directive for surface water in 9 out of 11 case study sites (CSS), and the total pesticide concentration surpassed the reference value of 500 ng/L in 8 CSS. Although only 5 % (bifenthrin, dieldrin, fipronil sulfone, permethrin, and terbutryn) of the individual pesticides denoted high risk (RQ > 1), the ratios estimated for pesticide mixtures suggested potential environmental risk in the aquatic compartment studied.

Impact of warm-up methods on strength-speed for sprinters in athletics: a mini review.

In athletics, achieving peak performance during competitions is crucial. Warm-up strategies play a crucial role in optimizing the strength-speed performance of sprinters in athletics, especially tailored to the physiological demands of speed events. The need to balance flexibility, prevent injuries, and enhance power output makes the selection of an effective warm-up protocol essential. This narrative review examines different warm-up methods used by athletes and their effects on strength-speed in sprinters in athletics. The main findings indicate that Foam Rolling (FR), Isometric Exercises and Pre-Competitive Massages have no significant effects on sprint performance. Static stretching and prolonged Pre-Competitive Massages have negative impacts on strength and power. The Vibration Platform enhances step length, step rate and running velocity, jump height and total number of jumps performed in a 30-s period in non-experienced sprinters. Eccentric Exercise increases vertical force, Post-Activation Potentiation (PAP) demonstrates a reduction in 100-meter time and short-term improvement in vertical and horizontal jumps. Blood Flow Restriction (BFR) significantly improving jump height and flight time. Various warm-up methods have been identified, some focusing on flexibility, others potentially detrimental, and some enhancing strength and power. Implementing effective warm-ups, particularly those promoting strength and power, poses a challenge for coaches seeking reliable alternatives to boost performance.

Resistance Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part III).

In the final part of this three-article collection on the training strategies of Brazilian Olympic sprint and jump coaches, we provide a detailed description of the resistance training methods and exercises most commonly employed by these speed experts. Always with the objective of maximizing the sprint and jump capabilities of their athletes, these experienced coaches primarily utilize variable, eccentric, concentric, machine-based, isometric, complex, and isoinertial resistance training methods in their daily practices. Squats (in their different forms), Olympic weightlifting, ballistics, hip thrusts, lunges, calf raises, core exercises, leg curls, stiff-leg deadlifts, and leg extension are the most commonly prescribed exercises in their training programs, during both the preparatory and competitive periods. Therefore, the current manuscript comprehensively describes and examines these methods, with the additional aim of extrapolating their application to other sports, especially those where sprint speed is a key performance factor.

Influence of Intensity on Post-Running Jump Potentiation in Recreational Runners vs. Physically Active Individuals.

The aim of this study was to verify post-activation performance enhancement (PAPE) in jumping and sprinting after two endurance volume-equated running protocols with different intensities, in runners vs. active individuals. Nine recreational runners (age: 34.5 ± 9.3 years, body mass: 73.1 ± 11.9 kg, body height: 1.76 ± 0.06 m, 17.4 ± 4.4 %body fat; maximum aerobic speed [MAS]: 16.4 ± 1.0 km•h-1), and 9 active individuals (age: 34.1 ± 9.4 years; body mass: 83.2 ± 7.7 kg; body height: 1.79 ± 0.06 m; 25.6 ± 5.4 %body fat; MAS: 13.3 ± 1.2 km•h-1) volunteered for participation. The evaluations were performed over three days as follows: 1) anthropometric measures, physical fitness tests, and the University of Montreal Track Test (UMTT) to determine MAS and the distance to be covered in the running protocols; 2 and 3) the countermovement jump (CMJ) and the flying 20-m sprint (SPRINT) were assessed pre- and post-running at 70% of MAS or a time trial race (TTR), equated by volume and completed in random order. A three-way ANOVA (time*group*running) was performed to analyze the PAPE effects. The results showed a time effect (F = 10 .716; p < 0.01) and a group*running interaction (F = 12.094; p < 0.01) for the CMJ, indicating that active individuals demonstrated PAPE after running at 70% of MAS, while for runners both running interventions (70% of MAS and TTR) induced PAPE in CMJ performances. For the SPRINT, a time*group interaction (F = 4.790; p = 0.044) and a group effect were observed, with runners showing greater SPRINT performances than active individuals. From the current results, it can be suggested that training background and intensity can modulate PAPE responses in jumping and sprinting after volume-equated running protocols at different intensities.

Match-Play Running Performance in Professional Male Soccer Players: The Role of Anaerobic Speed Reserve.

Purpose: This study aimed to compare match-play running performance between players with a high (HASR) and low (LASR) anaerobic speed reserve (ASR) profile in professional soccer players. Method: Thirty-six male players from the same club (age: 23.3 ± 5.4 years) took part in this study. Match data were collected from 43 home matches of the first and second division of the Brazilian National Championship over two consecutive seasons. Players had their maximal sprinting (MSS) and aerobic speeds (MAS) determined during field test-based assessments. ASR was defined as MSS minus MAS. Total distance (TD), sprinting distance, number of accelerations and decelerations, absolute peak (PMS(abs)) and mean match sprint speed (MMSS(abs)) and its relative values expressed as a percentage of MSS (PMS(rel) and MMSS(rel)), distance covered > 100% MAS(abs) and > 50% MSS(abs) were compared between the groups and halves. Results: HASR presented greater sprint demand (d > 0.80), PMS(abs) (d = 1.57), and MMSS(abs) (d = 0.99) than the LASR group. The opposite was observed for PMS(rel) and MMSS(rel). The TD and amount of high-intensity accelerations and decelerations were moderately (0.77MAS(abs) and > 50% MSS(abs) decreased between halves (d = 0.72 and 0.77), while the HASR did not (d < 0.10). Conclusion: Our findings indicated that players with larger ASR had greater sprint demand, with a lower relative running intensity, and covered longer distances above MAS. The amplitude of ASR also affected the player's running ability between halves.

Effects of oral HPΒCD-angiotensin-(1-7) supplementation on recreational mountain bike athletes: a crossover study.

BACKGROUND: Supplementation with Angiotensin-(1-7) [(Ang-1-7)] has received considerable attention due to its possible ergogenic effects on physical performance. The effects of a single dose of Ang-(1-7) on the performance of mountain bike (MTB) athletes during progressive load tests performed until the onset of voluntary fatigue have previously been demonstrated. This study tested the effects of Ang-(1-7) in two different exercise protocols with different metabolic demands: aerobic (time trial) and anaerobic (repeated sprint). METHODS: Twenty one male recreational athletes were given capsules containing an oral formulation of HPßCD-Ang-(1-7) (0.8 mg) and HPßCD-placebo (only HPßCD) over a 7-day interval; a double-blind randomized crossover design was used. Physical performance was examined using two protocols: a 20-km cycling time trial or 4 × 30-s repeated all-out sprints on a leg cycle ergometer. Data were collected before and after physical tests to assess fatigue parameters, and included lactate levels, and muscle activation during the sprint protocol as evaluated by electromyography (EMG); cardiovascular parameters: diastolic and systolic blood pressure and heart rate; and performance parameters, time to complete (time trial), maximum power and mean power (repeated sprint). RESULTS: Supplementation with an oral formulation of HPßCD-Ang-(1-7) reduced basal plasma lactate levels and promoted the maintenance of plasma glucose levels after repeated sprints. Supplementation with HPßCD-Ang-(1-7) also increased baseline plasma nitrite levels and reduced resting diastolic blood pressure in a time trial protocol. HPßCD-Ang-(1-7) had no effect on the time trial or repeat sprint performance, or on the EMG recordings of the vastus lateralis and vastus medialis. CONCLUSIONS: Supplementation with HPßCD-Ang-(1-7) did not improve physical performance in time trial or in repeated sprints; however, it promoted the maintenance of plasma glucose and lactate levels after the sprint protocol and at rest, respectively. In addition, HPßCD-Ang-(1-7) also increased resting plasma nitrite levels and reduced diastolic blood pressure in the time trial protocol. TRIAL REGISTRATION: RBR-2nbmpbc, registered January 6th, 2023. The study was prospectively registered.

Speed Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part II).

This is the second article in a three-article collection regarding the plyometric, speed, and resistance training practices of Brazilian Olympic sprint and jump coaches. Here, we list and describe six out of the ten speed training methods most commonly employed by these experts to enhance the sprinting capabilities of their athletes. Maximum speed sprinting, form running, resisted sprinting, overspeed running, uphill and downhill running, and sport-specific movement methods are critically examined with reference to their potential application in different sport contexts. In an era when sprint speed is of critical importance across numerous sports, practitioners can employ the methods outlined here to design efficient training programs for their athletes.

The CRAVE and ARGE scales for motivation states for physical activity and sedentarism: Brazilian Portuguese translation and single-item versions.

Motivation states for physical activity and sedentarism potentially vary from moment to moment. The CRAVE scale (Cravings for Rest and Volitional Energy Expenditure) was developed to assess transient wants and desires to move. Three studies were conducted with the aims of: (1) translating and validating the scale in Brazilian Portuguese, (2) examining changes with exercise, and (3) determining the best single-item for Move and Rest subscales for English and Portuguese. In Study 1, six bilingual speakers translated the scale into Brazilian Portuguese [named Anseios por Repouso e Gastos com Energia (ARGE)]. The ARGE had good content validity coefficients across three dimensions (0.89-0.91), as determined by three independent, bilingual referees. 1,168 participants (mean age = 30.6, SD = 12.2) from across Brazil completed an online version of the ARGE. An Exploratory Factor Analysis found two clear, oblique, and inversely related factors (Move and Rest; GFI = 1.00, RMSR = 0.03). Reliability was good (Cronbach α's: 0.93 and 0.92). Two models of the scale (10 vs. 13 items) were compared with Confirmatory Factor Analysis. The previously validated version using 10 scored items (GFI = 1.00, RMSEA = 0.07, RMSR = 0.02) outperformed the version scored with 13 items. State anxiety and exercise behavior had small associations with Move and Rest (-0.20 to 0.26). In Study 2, ARGE Move scores had high correspondence post-session (ICC = 0.83) for 9 women performing short Sprint Interval Training (sSIT; 6 sessions). Large, but non-significant, effects were detected for changes in motivation states with sSIT. In Study 3, IRT analyses found that for the United States sample, "be physically active" and "be still" were the most representative items for Move and Rest, respectively, while for the Brazil sample they were "exert my muscles" and "be a couch potato." Overall, it was found that: (A) the ARGE scale demonstrated good psychometric properties, (B) the original scoring (with 10 items) resulted in the best model, (C) it had small associations with exercise behavior, and (D) the subscales were reduced to single items that varied by country, indicating potential cultural differences in the concept of motivation states for physical activity.

Change-of-Direction and Deceleration Deficits in National-Team Female Rugby Sevens Players: Interrelationships and Associations With Speed-Related Performance.

PURPOSE: To investigate the relationships between a series of direct and indirect measures of linear and multidirectional speed performance in elite female rugby sevens players. METHODS: Nineteen players from the Brazilian national team performed 40-m linear sprint and 505 change-of-direction (COD) tests on the same day. Based on the linear sprint and COD test performances, the COD deficit (CODD) and deceleration deficit (DD) were also obtained. A Pearson product-moment correlation analysis was used to determine the relationships between linear sprint and COD-derived variables. RESULTS: Linear sprint and 505 COD velocities were not significantly associated (P > .05). Large to very large significant associations (r values ranging from .54 to .78; P < .05) were detected between linear sprint velocity for the different distances tested (10, 15, 30, and 40 m) and CODD. The COD velocity presented a very large inverse significant correlation with CODD and DD (r = -.77 and -.79 respectively; P < .05). A large and significant correlation was identified between CODD and DD (r = .79; P < .05). CONCLUSIONS: Significant associations were observed between linear sprint and CODD, suggesting that faster players are less efficient at changing direction. No relationship was found between sprint velocity and DD, highlighting the independent nature of linear sprints and deceleration capabilities. A comprehensive and detailed analysis of multidirectional speed performance should consider not only linear sprint and COD performances but also complementary COD-derived variables such as the CODD and DD.

Maximal pulmonary ventilation and lactate affect the anaerobic performance in young women exposed to hypobaric hypoxia.

Background: Athletes, tourists, and mining workers from all over the world ascend daily to an altitude greater than 3.000 meters above sea level to perform different activities, all of which demand physical effort. A ventilation increase is the first mechanism once the chemoreceptors perceive hypoxia, and is key to maintaining blood oxygen levels during acute exposure to high altitudes and to buffering lactic acidosis during exercise. It has been observed that gender is a variable that can influence the ventilatory response. Still, the available literature is limited due to the few studies considering women as study subjects. The influence of gender on anaerobic performance and its effects under high altitudes (HA) environments have been poorly studied. Objective: The objectives of this study were to evaluate anaerobic performance in young women exposed to high altitudes and to compare the physiological response to multiple sprints between women and men measured by ergospirometry. Methodology: Nine women and nine men (22.9 ± 3.2 years old) carried out the multiple-sprint anaerobic tests under two conditions, sea level and high altitudes. Results: In the first 24 h of exposure to a high altitudes, lactate levels were higher in women than those in men (2.57 ± 0.4 Mmol/L, 2.18 ± 0.3 Mmol/L, respectively; p < 0.05). Second, women had a decreased ventilatory response in exposure to high altitudes compared to men (p > 0.005). Third, there is a positive correlation between lactate levels prior to an anaerobic test and the ventilatory response developed by subjects at high altitudes (R2 = 0.33, slope = -41.7, and p < 0.05). Lastly, this ventilatory response can influence VO2peak (R2 = 0.60, slope = 0.02, and p < 0.001). Conclusion: This study provides insights into the mechanisms behind the reduced respiratory capacity observed in women during an anaerobic exercise test at high altitudes. An acute response to HA showed a greater work of breathing and increased the drive ventilatory response. It is possible to postulate the differences in the fatigue-induced metaboreflex of the respiratory muscles and aerobic-anaerobic transition between genders. These results on multiple sprint performance and the influences of gender in hypoxic environments deserve further investigation.

Metabolic responses to acute sprint interval exercise training performed after an oral 75-gram glucose load in individuals with overweight/obesity.

There is evidence supporting that acute sprint interval training (SIT) might improve metabolic responses to postprandial glucose, but results are inconclusive. The aim of the present study was to explore the effects of acute SIT on metabolic response and substrate utilization in individuals with overweight/obesity after an oral 75-gram glucose challenge. Thirty-three participants with overweight/ obesity (32.7 ± 8.3 years, 24 male, 9 female) participated in the study and a crossover design was followed. After the 75-gram glucose load, participants were randomly allocated to two groups: no exercise (resting) or SIT protocol. Metabolic data including respiratory quotient (RQ) and substrate utilization rates (fats and carbohydrates) were collected using the COSMED Q-NRG + ® calorimeter. The RQ was significantly lower in the acute SIT group (0.76 [0.01]; p < 0.0001) than in the resting group (0.80 [0.01]; p = 0.036) at the 120-min postprandial time point, and the RQ area under the curve (AUC) was also lower in the SIT group (mean difference of -6.62, 95% CI -12.00 to -1.24; p = 0.0161). The contribution of fat to energy expenditure increased after SIT during the postprandial period whereas the contribution of carbohydrates decreased. The AUC for fat contribution was significantly higher (mean difference 2311.9, 95% confidence interval [CI] 578.8 to 4043.3; p = 0.0098) and the AUC for carbohydrate contribution was significantly lower (mean difference -2283.1, 95% CI -4040.2 to -527.1; p = 0.0117) in the SIT group than in the resting group. In conclusions, acute SIT might have a positive effect on metabolic responses to postprandial glucose and, accordingly, should be recommended for improving metabolism in people with overweight/obesity.

Relationship between vertical jump tests and ice skating performance in junior Polish ice hockey players.

The aim of this study was to determine the relationships between vertical jumps (VJ) and various on-ice skating performances of junior ice hockey players (n = 19). The three modes of VJ or off-ice measures were countermovement jump with arm swing (CMJ), squat jump (SJ) and depth drop jump (DDJ). The on-ice skating performance was measured by the skating multistage aerobic test (SMAT), forward and backward acceleration test, top speed test, and repeated sprint ability (RSA) test. The relationships between the variables were quantified using Pearson's product-moment correlation. DDJ showed a significant positive correlation with forward average skating speed (FASS) (r = 0.62) and strong correlations with backward average skating speed (BASS) (r = 0.81), and maximum skating speed (MSS) (r = 0.71). SJ was found to be strongly correlated with BASS (r = 0.82) and MSS (r = 0.76), whereas the only on-ice performance that significantly correlated with CMJ was BASS (r = 0.68). All three modes of VJ were inversely and non-significantly correlated with performance decrement index and fatigue index, as determined by the RSA test. SMAT was not significantly correlated with either VJ or RSA. Correlations between all three modes of VJ tests were significant. Therefore, this study concludes that: (1) DDJ can be used as a predictor of all the ice skating speed tests, whereas SJ can predict BASS and MSS. CMJ, on the other hand, can predict the performance of only BASS. (2) RSA performance cannot be predicted from CMJ, SJ, or DDJ tests, and (3) neither any of the VJ nor RSA can predict skating endurance of junior ice hockey players.

Acute effects of different intervals between repeated sprints on performance responses in amateur futsal athletes / Efeitos agudos de diferentes intervalos entre sprint repetidos sobre as respostas de desempenho em atletas amadores de futsal

ABSTRACT Objective: Verify the influence of different break times between sprints on the performance of amateur futsal athletes. Methods: 10 individuals, men, amateur futsal athletes (Age: 21.5 ± 1.6; Weight: 72.4 ± 6.88; Height: 1.72 ± 0.05; BMI: 24.3 ± 1.2; Fat%: 13.7 ± 3.3, VO2peak: 49.1 ± 10.5) participated in the study. Individuals were randomly selected to perform sessions with sprints (10 sets 20 m) with different pause times of 15 (S15), 30 (S30) and 60 (S60) seconds. For performance analysis, the speed (km / h) applied to each sprint was used and monitored by a device with a photocell (CEFISE Biotecnologia Esportiva®). Results: There was an interaction between speed and interval time (p = 0.000). For condition S15, a greater reduction in performance was observed (p ≤ 0.05), while for S30 and S60, no significant reduction in performance was observed (p > 0.05). The data for the area under the curve showed a significant difference (p = 0.000), where the interval of 60 s (S60) was longer compared to the values of 30 (S30) (p = 0.000) and 15 s (S15) (p = 0.000). However, there were no significant differences between the 30 and 15 s data (p = 0.248). Conclusion: A shorter time (15 s) interval between repeated sprints can significantly affect performance compared to longer breaks (30 and 60 s), but all the conditions tested here can be positive for the improvement of performance, mainly in sports that demand fast and efficient motor actions such as futsal.

RESUMO Objetivo: Verificar a influência dos diferentes tempos de intervalo entre os sprints no desempenho dos atletas de futsal amadores. Métodos: 10 indivíduos, homens, atletas de futsal amadores (Idade: 21,5 ± 1,6; Peso: 72,4 ± 6,88; Altura: 1,72 ± 0,05; IMC: 24,3 ± 1,2; Gordura%: 13,7 ± 3,3, VO2peak: 49,1 ± 10,5) participou no estudo. Os indivíduos foram selecionados aleatoriamente para realizar sessões com sprints (10 conjuntos 20 m) com diferentes tempos de pausa de 15 (S15), 30 (S30) e 60 (S60) segundos. Para análise do desempenho, a velocidade (km/h) aplicada a cada sprint foi utilizada e monitorizada por um dispositivo com uma fotocélula (CEFISE Biotecnologia Esportiva®). Resultados: Houve uma interação entre velocidade e tempo de intervalo (p = 0,000). Para a condição S15, observou-se uma maior redução no desempenho (p ≤ 0,05), enquanto para S30 e S60, não se observou qualquer redução significativa no desempenho (p > 0,05). Os dados para a área sob a curva mostraram uma diferença significativa (p = 0,000), onde o intervalo de 60 s (S60) foi mais longo em comparação com os valores de 30 (S30) (p = 0,000) e 15 s (S15) (p = 0,000). No entanto, não houve diferenças significativas entre os dados de 30 e 15 s (p = 0,248). Conclusão: Um intervalo de tempo mais curto (15 s) entre sprints repetidos pode afetar significativamente o desempenho em comparação com os intervalos mais longos (30 e 60 s), mas todas as condições aqui testadas podem ser positivas para a melhoria do desempenho, principalmente nos desportos que exigem ações motoras rápidas e eficientes, tais como o futsal.