Effects of acute caffeine intake on combat sports performance: A systematic review and meta-analysis.

The interest in the benefits of caffeine in combat sports has grown exponentially in the last few years, evidenced by the significant rise of post-competition urine caffeine concentration. We conduct a systematic review and meta-analysis on the effects of caffeine on different performance variables in combat sports athletes. In total, we included 25 studies. All studies included had blinded, and cross-over experimental designs, and we conducted a risk of bias analysis. For nonspecific outcomes, there was an ergogenic effect of caffeine on vertical jump height (SMD: 0.38; 95% CI: 0.04, 0.71) and reaction time (SMD: -0.98, 95% CI: -1.46,-0.50). For outcomes specific to combat sports, there was an increase in the number of throws with caffeine in the Special Judo Fitness Test (SMD: 0.62; 95% CI: 0.14, 1.09). Caffeine ingestion increased the number of offensive actions during combats (SMD: 0.40; 95% CI: 0.06, 0.74). Caffeine ingestion increased the duration of offensive actions during combat (SMD: 0.58; 95% CI: 0.21, 0.96). Finally, caffeine ingestion increased blood lactate concentration after bout 1 (SMD: 1.35) bout 2 (SMD: 1.43) and bout 3 (SMD: 1.98). Overall, athletes competing in combat sports may consider supplementing with caffeine for an acute increase in exercise performance.

Muscle hypertrophy induced by N-3 PUFA supplementation in absence of exercise: a systematic review of randomized controlled trials.

The use of omega-3 polyunsaturated fatty acids (n-3 PUFA) has been studied in physically active population, however, there is a lack of information about the effects of n-3 PUFA supplementation on people with a sedentary behavior or who are undergoing a period of limb immobilization. This systematic review aims to examine the effect of n-3 PUFA on lean mass and muscle protein synthesis (MPS) in absence of physical training. The PubMed, Web of Science, MEDLINE, CINAHL and SPORTDiscus databases were searched following the PRISMA guidelines. Only randomized controlled trials, at least single blind, performed with sedentary humans were considered. Seven studies on a total of 192 individuals were included. Five of the six studies which measured changes in skeletal muscle volume and mass showed higher values with n-3 PUFA. Only two studies measured skeletal muscle protein expression. Both showed beneficial effects of supplementation in muscle protein fractional synthesis rate (FSR), while no effect of n-3 PUFA was observed for mechanistic target of rapamycin (mTOR) and kinase protein (Akt). In addition, ribosomal protein S6 kinase 1 (p70s6k) improved with n-3 PUFA only in one study. Finally, the two studies which measured the skeletal muscle gene expression observed no effect of supplementation.

Effect of ß-alanine and sodium bicarbonate co-supplementation on the body's buffering capacity and sports performance: A systematic review.

Muscle acidification is one of the main factors causing fatigue during exercise, thus compromising performance. The sport supplements beta alanine (ß-A) and sodium bicarbonate (SB) are thought to enhance the effects of the body's buffer systems by reducing H+ concentrations. The aim of this systematic review was to analyze the effects of ß-A and SB co-supplementation on the organism's buffering capacity and sport performance. The databases PubMed, Web of Science, Medline, CINAHL and SPORTDiscus were searched until November 2021 following PRISMA guidelines. Randomized controlled trials, at least single-blind, performed in athletes of any age were considered. Nine studies including a total of 221 athletes were identified for review. Athletes were supplemented with ß-A and SB while they performed exercise tests to assess physical performance and buffer capacity. Five of the nine studies indicated there was some additional improvement in buffering capacity and performance with co-supplementation, while one study concluded that the effect was comparable to the added effects of the individual supplements. According to the results of the studies reviewed, we would recommend ß-A and SB co-supplementation during high intensity exercises lasting between 30 s and 10 min.

Analysis of the most demanding passages of play in elite youth soccer: a comparison between congested and non-congested fixture schedules.

This study aimed to examine the most demanding passages of play in elite youth soccer for congested and non-congested fixture schedules. Seventeen elite youth male soccer players (18.2 ± 1.3 years old) participated in this study across 30 competitive matches. Assessed matches included congested (n = 12, three matches within eight consecutive days or less) and non-congested matches (n = 18, at least 5 days between matches). The players' activity profiles during matches were analysed using global positioning measurement units (GPS). Players activity included: distance covered, distance covered at different velocities, high-intensity accelerations and decelerations, and player load. The most demanding passages (MDP) of match play was calculated using a moving average method within three-time windows (i.e., 1, 5, and 10 min). Data were analysed using a Bayesian ANOVA. During congested fixtures, the players' distance covered and player load declined, with the former decreasing across all the MDP time windows, whereas the latter exclusively into the long-time windows (i.e., 5 and 10 min). Conversely, statistical differences in the remaining variables were anecdotal and in favour of the null hypothesis (i.e., Bayes factor <1), suggesting a non-influence of the competition fixture schedule. These findings provide insight into the MDP of youth soccer, helping practitioners to periodize training and recovery strategies during different competitive fixture schedules.

Effects of Concurrent Resistance and Endurance Training Using Continuous or Intermittent Protocols on Muscle Hypertrophy: Systematic Review With Meta-Analysis.

ABSTRACT: Monserdà-Vilaró, A, Balsalobre-Fernández, C, Hoffman, JR, Alix-Fages, C, and Jiménez, SL. Effects of concurrent resistance and endurance training using continuous or intermittent protocols on muscle hypertrophy: Systematic review with meta-analysis. J Strength Cond Res 37(3): 688-709, 2023-The purpose of this systematic review with meta-analysis was to explore the effects of concurrent resistance and endurance training (CT) incorporating continuous or intermittent endurance training (ET) on whole-muscle and type I and II muscle fiber hypertrophy compared with resistance training (RT) alone. Randomized and nonrandomized studies reporting changes in cross-sectional area at muscle fiber and whole-muscle levels after RT compared with CT were included. Searches for such studies were performed in Web of Science, PubMed, Scopus, SPORTDiscus, and CINAHL electronic databases. The data reported in the included studies were pooled in a random-effects meta-analysis of standardized mean differences (SMDs). Twenty-five studies were included. At the whole-muscle level, there were no significant differences for any comparison (SMD < 0.03). By contrast, RT induced greater type I and type II muscle fiber hypertrophy than CT when high-intensity interval training (HIIT) was incorporated alone (SMD > 0.33) or combined with continuous ET (SMD > 0.27), but not compared with CT incorporating only continuous ET (SMD < 0.16). The subgroup analyses of this systematic review and meta-analysis showed that RT induces greater muscle fiber hypertrophy than CT when HIIT is included. However, no CT affected whole-muscle hypertrophy compared with RT.

Effects of Nitrate Supplementation on Muscle Strength and Mass: A Systematic Review.

ABSTRACT: Anderson, OK, Martinez-Ferran, M, Lorenzo-Calvo, J, Jiménez, SL, and Pareja-Galeano, H. Effects of nitrate supplementation on muscle strength and mass: a systematic review. J Strength Cond Res 36(12): 3562-3570, 2022-This systematic review examines the effect of dietary nitrate supplementation (SUP) on muscle strength and hypertrophy when combined with physical exercise. The databases PubMed, Web of Science, and MEDLINE were searched for full-text articles published between January 2000 and June 2020. For inclusion, studies had to report on the effects of SUP administered as acute or chronic doses together with a standardized exercise protocol on muscle strength and hypertrophy compared with placebo in healthy adults who were sedentary, physically active, or professional athletes. Twelve studies (1,571 subjects) were finally selected. In 5 studies, the SUP regime was acute, and in 7, it was chronic. SUP was nitrate-rich beetroot juice in 9 studies, a potassium nitrate capsule in 1, and increased dietary nitrate in 2. Ingested nitrate was 64-1,200 mg. Of the 12 studies, 6 observed an ergogenic effect of SUP compared with placebo. These findings indicate that muscle strength gains are possible provided the dose, format, frequency, period, and exercise test are appropriate. Best results were observed with a minimum acute dose of 400 mg of nitrate provided as beetroot juice/shot taken 2-2.5 hours before exercise involving low- and high-intensity muscle contractions. This SUP regime seems to improve muscle efficiency in terms of reduced phosphocreatine and energy costs (P-magnetic resonance spectroscopy) and improved time to exhaustion.

Synergy of carbohydrate and caffeine ingestion on physical performance and metabolic responses to exercise: A systematic review with meta-analysis.

Carbohydrates (CHO) and caffeine (CAF) are two ergogenic aids commonly used among athletes to enhance performance. However, there is some controversy as to whether the concurrent intake of both supplements might result in an additive and synergistic improvement in exercise performance. The aim of this systematic review and meta-analysis was to determine the effect of adding CAF to a protocol of CHO ingestion, compared with the intake of each ergogenic aid alone and with placebo, on exercise performance and metabolic responses in healthy young physically active adults. This study was conducted according to PRISMA 2020 guidelines. The PubMed, Web of Science, Medline Complete, CINAHL, SPORTDiscus and CENTRAL databases were searched including randomized controlled trials (RCT) that were at least single blind. The risk of bias assessment was performed using the Cochrane Risk-of-Bias tool 2. Meta-analysis were performed on performance variables and rating of perceived exertion (RPE) using the random-effects model. Thirteen RCT with 128 participants (117 men and 11 women) were included in this study. The ingestion of CAF and CHO reduced sprint time during repeated sprint protocols in comparison with CHO isolated ingestion (SMD: -0.45; 95% CI: -0.85, -0.05) while there was a tendency for a reduction in the time employed during time trials (SMD: -0.36; 95% CI: -0.77, 0.05). The RPE tended to be lower with CAF and CHO compared with CHO isolated ingestion during steady-state exercise (SMD: -0.43; 95% CI: -0.91, 0.05) with no differences between conditions in performance trials (SMD: -0.05, 95% CI: -0.39, 0.29). Although most of the studies showed higher values of blood glucose when CHO was co-ingested with CAF compared with PLA, only two studies observed higher values with CHO and CAF co-ingestion with respect to the isolated intake of CHO. One study observed greater fat oxidation and lower glycogen use when CAF was added to CHO. In terms of cortisol levels, one study showed an increase in cortisol levels when CAF was co-ingested with CHO compared with PLA. In summary, concurrent CHO and CAF intake may produce an additive ergogenic effect respect of the isolated ingestion of CHO. This additive effect was present when CHO was provided by a 6-9% of CHO solution (maltodextrin/dextrin + fructose) and CAF is administered in a dose of 4-6.5 mg/kg.

Fluctuations in External Peak Demands Across Quarters During Basketball Games.

The purpose of this study was to compare external peak demands (PDs) across quarters (Q) in basketball. Thirteen elite, junior, male basketball players were monitored using electronic performance tracking systems. There were studied intervals for different time windows to determine the external PD for distance (m); player load; distance covered in four different zones; accelerations; and decelerations. A mixed linear model was run to identify differences among quarters, and the auto-correlation function was carried out to determine fluctuations across the whole game. The results showed significant differences between Q1 vs. Q2 for distance, player load, and standing-walking distance; between Q1 vs. Q3 for distance, player load, and HSR; between Q1 vs. Q4 for distance, player load, standing-walking, and HSR; and between Q3 vs. Q4 for distance and player load. These findings suggest that external PD for running-based demands (distance, player load, and high-speed running) decrease across basketball games with the most notable declines occurring between the first and fourth quarters. Nevertheless, it is important to note that non-significant differences were found between quarters for several external PD variables (jogging, running, acceleration, and deceleration) across different time windows. Findings from the present study reinforce the importance of considering specific PD variables for different functions due to the specific insight each provides.

Caffeinated Drinks and Physical Performance in Sport: A Systematic Review.

Caffeine (1,3,7-trimethylxanthine) is one of the most common substances used by athletes to enhance their performance during competition. Evidence suggests that the performance-enhancing properties of caffeine can be obtained by employing several forms of administration, namely, capsules/tablets, caffeinated drinks (energy drinks and sports drinks), beverages (coffee), and chewing gum. However, caffeinated drinks have become the main form of caffeine administration in sport due to the wide presence of these products in the market. The objective of this systematic review is to evaluate the different effects of caffeinated drinks on physical performance in various sports categories such as endurance, power-based sports, team sports, and skill-based sports. A systematic review of published studies was performed on scientific databases for studies published from 2000 to 2020. All studies included had blinded and cross-over experimental designs, in which the ingestion of a caffeinated drink was compared to a placebo/control trial. The total number of studies included in this review was 37. The analysis of the included studies revealed that both sports drinks with caffeine and energy drinks were effective in increasing several aspects of sports performance when the amount of drink provides at least 3 mg of caffeine per kg of body mass. Due to their composition, caffeinated sports drinks seem to be more beneficial to consume during long-duration exercise, when the drinks are used for both rehydration and caffeine supplementation. Energy drinks may be more appropriate for providing caffeine before exercise. Lastly, the magnitude of the ergogenic benefits obtained with caffeinated drinks seems similar in women and men athletes. Overall, the current systematic review provides evidence of the efficacy of caffeinated drinks as a valid form for caffeine supplementation in sport.

Supplementation with Vitamins C and E and Exercise-Induced Delayed-Onset Muscle Soreness: A Systematic Review.

Muscle damage induced by exercise may have several consequences such as delayed-onset muscle soreness, a side-effect of the release of free radicals during oxidative stress. To mitigate the oxidative stress cascade, the oral intake of antioxidants has been assessed by several research groups. This review examines whether supplementation with vitamin C and/or vitamin E is able to prevent or attenuate delayed-onset muscle soreness after eccentric exercise. The PubMed, Web of Science, Medline, and Embase databases were searched to identify studies meeting the inclusion criteria: primary randomized control trials, healthy male and female participants aged 16-80 years, and an intervention consisting of the intake of vitamin C and/or vitamin E without other supplements plus a controlled eccentric exercise regimen. Further requirements were the measurement of muscle soreness or markers of delayed-onset muscle soreness. All original full-text articles in English or translated into English published from January 2000 to June 2020 were considered for this review. Fourteen studies were finally identified, including 280 participants, 230 men, and 50 women aged 16-30 years. All participants were healthy individuals with different starting levels of physical activity. Supplementation was acute in two studies and chronic in 12, and its consisted of vitamin C in eight studies, vitamin E in two studies, and both in four studies. Only in 3 of the 14 studies was muscle soreness found to be significantly reduced in response to vitamin C and/or vitamin E supplementation at all time points when compared to the placebo group. Despite some studies showing the beneficial effects of chronic supplementation with these vitamins on muscle soreness manifesting 24-72 h after eccentric exercise, the evidence is so far insufficient to confirm that the intake of antioxidant vitamins is able to minimize delayed-onset muscle soreness in this context.

Circulating microRNAs fluctuations in exercise-induced cardiac remodeling: A systematic review.

MicroRNAs (miRNAs) are small non-coding RNAs that participate in gene expression regulation. It has been observed that circulating levels of miRNAs may fluctuate during exercise, showing numerous cardiac biological and physiological effects such as structural and functional adaptations. We aimed to provide an overview of the currently available information concerning the role of circulating miRNAs in cardiovascular adaptations in response to acute and/or chronic exercise training. Relevant studies published were searched in three databases: PubMed, Web of Science and Scopus. A combination of the following keywords was used: ("microRNA" OR "miRNA" OR "miR" AND "exercise" OR "training" OR "physical activity") AND "(heart hypertrophy" OR "cardiac remodeling" OR "cardiac muscle mass" OR "cardiac hypertrophy"). Only experimental studies, written in English and conducted in healthy individuals were included. Five articles met the inclusion criteria and were finally included in this systematic review after reviewing both title, abstract and full-text. A total of thirty-six circulating cardiac-related miRNAs were analyzed, but only five of them (miR-1, miR-133a, miR-146a, miR-206 and miR-221) were directly associated with cardiac adaptations parameters, while two of them (miR-1 and miR-133a) were related to cardiac hypertrophy. Most of them were upregulated immediately after a marathon and returned to basal levels at longer times. Therefore, we conclude that, although evidence is still limited, and long-term studies are needed to obtain more robust evidence, exercise is more likely to affect circulating cardiac-related miRNAs levels.

Inspiratory Muscle Training in Intermittent Sports Modalities: A Systematic Review.

The fatigue of the respiratory muscles causes the so-called metabolic reflex or metaboreflex, resulting in vasoconstriction of the blood vessels in the peripheral muscles, which leads to a decrease in respiratory performance. Training the respiratory muscles is a possible solution to avoid this type of impairment in intermittent sports. The objective of this systematic review was to evaluate the results obtained with inspiratory muscle training (IMT) in intermittent sports modalities, intending to determine whether its implementation would be adequate and useful in intermittent sports. A search in the Web of Science (WOS) and Scopus databases was conducted, following the Preferred Reporting Elements for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The methodological quality of the articles was assessed using the PEDro (Physiotherapy Evidence Database) scale. In conclusion, the introduction of specific devices of IMT seems to be a suitable method to improve performance in intermittent sports, mainly due to a reduction of the metaboreflex, fatigue sensation, and dyspnea. The ideal protocol would consist of a combination of acute and chronic treatment, and, even if IMT is done daily, the duration will not exceed one hour per week.

Influence of Nitrate Supplementation on Endurance Cyclic Sports Performance: A Systematic Review.

Endurance can be defined as the capacity to maintain one's velocity or power output for the longest possible time. Maintaining such activity can lead to the onset of fatigue. Dietary nitrate supplementation produces an ergogenic effect due to the improvement of mitochondrial oxygen efficiency through a reduction in the oxygen cost of exercise that increases vasodilation and blood flow to the skeletal muscle in recreationally active subjects. However, the effects of dietary nitrate supplementation on well-trained endurance athletes remain unclear; such supplementation could affect more performance areas. In the present study, a systematic review of the literature was conducted to clarify the use and effects of nitrate as a dietary supplement in endurance athletes trained in cyclic sports (repetitive movement sports). A systematic search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the databases of SCOPUS, Web of Science (WOS), Medline (PubMed), and Sport Discus from 1 January 2010 to 30 November 2019. Twenty-seven studies were included in the study. The methodological quality of the articles was assessed using the McMaster Critical Review Form. Statistically significant ergogenic results were obtained in 8 (29.63%) of the 27 studies investigated, with significant results obtained for cardiorespiratory parameters and performance measures. Improvement in exercise tolerance was obtained, which could help with exhaustion over time, while the improvement in exercise economics was not as clear. Additionally, the dose necessary for this ergogenic effect seems to have a direct relationship with the physical condition of the athlete. The acute dose is around 6-12.4 mmol/day of nitrate administered 2-3 h before the activity, with the same amount given as a chronic dose over 6-15 days. Further studies are required to understand the factors that affect the potential ergogenic impacts of nitrate on athletic performance among endurance athletes.

Comparing the External Loads Encountered during Competition between Elite, Junior Male and Female Basketball Players.

The aim of the present study was to compare external loads (EL) between elite, junior, male and female basketball players. Male (n = 25) and female players (n = 48) were monitored during 11 competitive matches (3 matches per team). EL was measured using local positioning system and microsensor technology to determine total, high-intensity (14-21 km·h-1), and sprint (>21 km·h-1) distance (m) covered, total (n) and relative (n·min-1) accelerations and decelerations, ratio of accelerations:decelerations, and total (arbitrary units [AU]) and relative (AU·min-1) player load. EL was compared between sexes overall and according to each playing position (guards, forwards, and centers). Males covered larger (p < 0.05) high-intensity and sprint distances, and completed more (p < 0.05) decelerations than females; while female players experienced a greater (p < 0.05) ratio of accelerations:decelerations. Greater decelerations (p < 0.05) were observed for males in the guard position compared to females, while more (p < 0.05) accelerations·min-1 were apparent for females in the forward position compared to males. The current findings indicate differences in EL, particularly the high-intensity and acceleratory demands, exist between elite, junior, male and female basketball players during competition and are affected by playing position. These outcomes can be used in developing sex- and position-specific training plans, and in turn improving the physical preparedness of junior basketball players for competition demands at the elite level.

Bilateral and unilateral load-velocity profiling in a machine-based, single-joint, lower body exercise.

BACKGROUND: To analyze the goodness of fit of the load-velocity relationship in a machine-based, single-joint exercise performed both in a bilateral and unilateral manner, as well as to study its accuracy to estimate one repetition maximum (1-RM). METHODS: Fifteen resistance trained males performed an incremental test in the bilateral and unilateral leg extension exercise up to the 1-RM in two separate occasions. Mean vertical velocity of the weight plates in the leg extension machine was measured for every repetition using a smartphone application (My Lift). RESULTS: Linear regression analyses showed a high goodness of fit (R2 > 0.93) and small standard errors of estimate (SEE < 5%1-RM) both in the bilateral and unilateral leg extension when individual load-velocity regressions for each participant were computed. Unilateral load-velocity relationships showed significant differences in the intercept of the regression line with the Y-axis and the velocity at each percentage of the 1-RM (Cohen's d > 1.0, p< 0.05). Finally, non-significant differences were observed between actual and estimated 1-RM from the load-velocity relationships (r = 0.88.0-96, Cohen's d < 0.2, p> 0.05). CONCLUSIONS: This proof of concept highlights that computing load-velocity relationships in a machine-based, single-joint, angular exercise can be appropriately performed by measuring the mean vertical velocity of the weight plates. These results could help strength and conditioning researchers and coaches who wish to analyze load-velocity relationship in other common machine-based exercises.

Monitoring and Interpreting External Load in Basketball: A Narrative Review / Monitoreo e Interpretación de la Carga Externa en el Baloncesto: Una Revisión Narrativa

External load monitoring brings valuable information to practitioners and coaches about the physical requirements of the activity developed by their players, according to their level of competition, age and gender. This information can be used to individualize training programs and to optimize the time invested in them, making coaches and players more efficient in the process. This review asses the results reflected in the existing bibliography about the measurements of external load in the sport of basketball, synthesizing them in one article for the scientific reader. Data from 29 scientific papers has been organized and discussed, providing relevant insights about the goals and findings, sample, measurement variables and technology for monitoring external load in basketball

La monitorización de la carga externa aporta información valiosa a los profesionales y entrenadores sobre los requisitos físicos de la actividad desarrollada por sus jugadores, de acuerdo con su nivel de competencia, edad y género. Esta información se puede utilizar para individualizar los programas de entrenamiento y optimizar el tiempo invertido en ellos, haciendo que los entrenadores y jugadores sean más eficientes en el proceso. Esta revisión evalúa los resultados reflejados en la bibliografía existente sobre las medidas de carga externa en el deporte del baloncesto, sintetizándolas en un artículo para el lector científico. Los datos de 29 artículos científicos se han organizado y discutido, proporcionando información relevante sobre los objetivos y hallazgos, muestra, variables de medición y tecnología para monitorizar la carga externa en el baloncesto

O monitoramento de carga externa traz informações valiosas para os praticantes e treinadores sobre as exigências físicas da atividade desenvolvida por seus jogadores, de acordo com seu nível de competição, idade e sexo. Essas informações podem ser usadas para individualizar programas de treinamento e otimizar o tempo investido neles, tornando treinadores e jogadores mais eficientes no processo. Esta revisão avalia os resultados refletidos na bibliografia existente sobre as medidas de carga externa no esporte de basquete, sintetizando-as em um artigo para o leitor científico. Dados de 29 trabalhos científicos foram organizados e discutidos, fornecendo insights relevantes sobre os objetivos e descobertas, amostra, variáveis de medição e tecnologia para monitorar a carga externa no basquete

Comparison of the Movement Characteristics Based on Position-Specific Between Semi-Elite and Elite Basketball Players / Comparación de las Características de Movimiento Basadas en la Posición Específica entre los Jugadores de Baloncesto Semi-elite y Elite / Comparação das características do movimento baseadas na posição específica entre jogadores de basquete semi-elite e elite

The aim of study is to comparison of the movement characteristics based on position-specific between world-class elite and semi-elite basketball players. 24 basketball players were selected from Spanish U18 semi-elite (Guards = 5; Forwards = 5; Centres = 2) and World-class elite basketball players (Guards = 5; Forwards = 4; Centres = 3), respectively. Physical demands were assessed using WIMU PRO Local Positioning System (Realtrack Systems, Almeria, Spain) during practices. The differences between Spanish U18 semi-elite and World-class elite basketball players from different position were tested by independent sample t-test. Our result showed that Spanish U18 semi-elite basketball players from all position, made more movement of acceleration and deceleration per average minutes than their counterpart World-class basketball players. Moreover, Spanish U18 guards have better performance in the performance profiles of g-force acceleration (ES = 0.88) and deceleration (ES = 0.98) than World-class guards, as the same results as Spanish U18 centres (g-force acceleration, ES = 0.44; and g-force deceleration, ES = 0.53). Conversely, World-class forwards have better performance in max acceleration (ES = 0.42) and deceleration (ES = 0.42) than Spanish U18 forwards. In conclusion, differences in distribution of accelerations and decelerations appeared between player positions, which would be of importance when monitoring training and game loads and when prescribing specific training exercises

El objetivo del estudio ha sido comparar las características de los movimientos realizados por los jugadores de baloncesto, de acuerdo a la posición específica de juego, en jugadores de élite y semi-élite. Se seleccionaron 24 jugadores de baloncesto semi-elite U18 (Bases = 5; Aleros = 5; Pivots = 2) y jugadores de élite de clase mundial (Bases = 5; Aleros = 4; Pivots = 3), respectivamente. Las demandas físicas se evaluaron utilizando el sistema de posicionamiento local WIMU PRO (Realtrack Systems, Almería, España) durante los entrenamientos. Para observar las diferencias entre los jugadores de baloncesto semi-elite U18 y de élite de clase mundial desde diferentes posiciones se utilizó la prueba t de muestra independiente. Los resultados mostraron que los jugadores de baloncesto semi-elite U18, independientemente de la posición de juego, hicieron más movimientos de aceleración y desaceleración por minuto promedio que los jugadores de baloncesto de clase mundial. Además, los bases U18 tuvieron un mejor rendimiento en los perfiles de rendimiento de aceleración de fuerza g (ES = 0.88) y desaceleración (ES = 0.98) que los bases de clase mundial, al igual que los pivots españoles U18 (g- aceleración de fuerza, ES = 0.44; y desaceleración de fuerza g, ES = 0.53). Por el contrario, los aleros de clase mundial tuvieron un mejor rendimiento en aceleración máxima (ES = 0.42) y desaceleración (ES = 0.42) que los aleros U18. En conclusión, aparecieron diferencias en la distribución de las aceleraciones y desaceleraciones entre las posiciones de los jugadores, lo que sería importante al monitorear el entrenamiento y las cargas del juego y al prescribir ejercicios de entrenamiento específicos

O objectivo do estudo foi o de comparar as características dos movimentos realizados pelos jogadores de basquetebol, de acordo com a posição de reprodução em reprodutores de elite e semi-elite. Foram selecionados 24 jogadores de basquete sub-elite de sub-18 (Armadores = 5; Alas = 5; Pivôs = 2) e jogadores de elite da classe mundial (Armadores = 5; Alas = 4; Pivôs = 3), respectivamente. As demandas físicas foram avaliadas usando o sistema de posicionamento local WIMU PRO (Realtrack Systems, Almería, Espanha) durante o treinamento. Para observar as diferenças entre os jogadores de basquete semi-elite e elite de basquete de classe mundial de diferentes posições, foi utilizado o teste t de amostra independente. Os resultados mostraram que os jogadores de basquete Sub-18 semi-elite, independentemente da posição de jugego, fez mais movimentos de aceleração e desaceleração por classe média minuto mundo jogadores de basquete. Além disso, as armadores U18 tiveram melhor desempenho nos perfis de aceleração da força g (ES = 0,88) e desaceleração (ES = 0,98) do que as bases de classe mundial, assim como os pivôs espanhóis da U18 ( g- aceleração da força, ES = 0,44; e desaceleração da força g, ES = 0, 53). Pelo contrário, a classe alas mundo realizado melhor em aceleração máxima (ES = 0 .42) e desaceleração (ES = 0 0,42) do que beirais U18. Em conclusão, eles apareceram diferenças na distribuição de acelerações e desacelerações entre as posições dos jogadores, seria importante para monitorar treinamento e jogo carrega e ao prescrever exercícios específicos de formação

Validity and reliability of a novel iPhone app for the measurement of barbell velocity and 1RM on the bench-press exercise.

The purpose of this study was to analyse the validity and reliability of a novel iPhone app (named: PowerLift) for the measurement of mean velocity on the bench-press exercise. Additionally, the accuracy of the estimation of the 1-Repetition maximum (1RM) using the load-velocity relationship was tested. To do this, 10 powerlifters (Mean (SD): age = 26.5 ± 6.5 years; bench press 1RM · kg-1 = 1.34 ± 0.25) completed an incremental test on the bench-press exercise with 5 different loads (75-100% 1RM), while the mean velocity of the barbell was registered using a linear transducer (LT) and Powerlift. Results showed a very high correlation between the LT and the app (r = 0.94, SEE = 0.028 m · s-1) for the measurement of mean velocity. Bland-Altman plots (R2 = 0.011) and intraclass correlation coefficient (ICC = 0.965) revealed a very high agreement between both devices. A systematic bias by which the app registered slightly higher values than the LT (P < 0.05; mean difference (SD) between instruments = 0.008 ± 0.03 m · s-1). Finally, actual and estimated 1RM using the app were highly correlated (r = 0.98, mean difference (SD) = 5.5 ± 9.6 kg, P < 0.05). The app was found to be highly valid and reliable in comparison with a LT. These findings could have valuable practical applications for strength and conditioning coaches who wish to measure barbell velocity in the bench-press exercise.

Analysis of Wearable and Smartphone-Based Technologies for the Measurement of Barbell Velocity in Different Resistance Training Exercises.

The purpose of this study was to analyze the validity, reliability, and accuracy of new wearable and smartphone-based technology for the measurement of barbell velocity in resistance training exercises. To do this, 10 highly trained powerlifters (age = 26.1 ± 3.9 years) performed 11 repetitions with loads ranging 50-100% of the 1-Repetition maximum in the bench-press, full-squat, and hip-thrust exercises while barbell velocity was simultaneously measured using a linear transducer (LT), two Beast wearable devices (one placed on the subjects' wrist -BW-, and the other one directly attached to the barbell -BB-) and the iOS PowerLift app. Results showed a high correlation between the LT and BW (r = 0.94-0.98, SEE = 0.04-0.07 m•s-1), BB (r = 0.97-0.98, SEE = 0.04-0.05 m•s-1), and the PowerLift app (r = 0.97-0.98, SEE = 0.03-0.05 m•s-1) for the measurement of barbell velocity in the three exercises. Paired samples T-test revealed systematic biases between the LT and BW, BB and the app in the hip-thrust, between the LT and BW in the full-squat and between the LT and BB in the bench-press exercise (p < 0.001). Moreover, the analysis of the linear regression on the Bland-Altman plots showed that the differences between the LT and BW (R2 = 0.004-0.03), BB (R2 = 0.007-0.01), and the app (R2 = 0.001-0.03) were similar across the whole range of velocities analyzed. Finally, the reliability of the BW (ICC = 0.910-0.988), BB (ICC = 0.922-0.990), and the app (ICC = 0.928-0.989) for the measurement of the two repetitions performed with each load were almost the same than that observed with the LT (ICC = 0.937-0.990). Both the Beast wearable device and the PowerLift app were highly valid, reliable, and accurate for the measurement of barbell velocity in the bench-press, full-squat, and hip-thrust exercises. These results could have potential practical applications for strength and conditioning coaches who wish to measure barbell velocity during resistance training.