Effect of Acute Sodium Bicarbonate and Caffeine Coingestion on Repeated-Sprint Performance in Recreationally Trained Individuals: A Randomized Controlled Trial.

INTRODUCTION: The acute and isolated ingestion of sodium bicarbonate (NaHCO3) and caffeine (CAF) improves performance and delays fatigue in high-intensity tasks. However, it remains to be elucidated if the coingestion of both dietary supplements stimulates a summative ergogenic effect. This study aimed to examine the effect of the acute coingestion of NaHCO3 and CAF on repeated-sprint performance. METHODS: Twenty-five trained participants (age: 23.3 [4.0] y; sex [female/male]: 12/13; body mass: 69.6 [12.5] kg) participated in a randomized, double-blind, placebo (PLA) -controlled, crossover study. Participants were assigned to 4 conditions: (1) NaHCO3 + CAF, (2) NaHCO3, (3) CAF, or (4) PLA. Thus, they ingested 0.3 g/kg of NaHCO3, 3 mg/kg of CAF, or PLA. Then, participants performed 4 Wingate tests (Wt), consisting of a 30-second all-out sprint against an individualized resisted load, interspersed by a 1.5-minute rest period between sprints. RESULTS: Peak (Wpeak) and mean (Wmean) power output revealed a supplement and sprint interaction effect (P = .009 and P = .049, respectively). Compared with PLA, NaHCO3 + CAF and NaHCO3 increased Wpeak performance in Wt 3 (3%, P = .021) and Wt 4 (4.5%, P = .047), while NaHCO3 supplementation increased mean power performance in Wt 3 (4.2%, P = .001). In Wt 1, CAF increased Wpeak (3.2%, P = .054) and reduced time to Wpeak (-8.5%; P = .008). Plasma lactate showed a supplement plus sprint interaction (P < .001) when NaHCO3 was compared with CAF (13%, P = .031) and PLA (23%, P = .021). CONCLUSION: To summarize, although the isolated ingestion of CAF and NaHCO3 improved repeated-sprint performance, the coingestion of both supplements did not stimulate a synergic ergogenic effect.

Exercise facility availability and incidence of type 2 diabetes and complications in Spain: A population-based retrospective cohort 2015-2018.

BACKGROUND: To study the association between exercise facility availability and type 2 diabetes incidence and its complications, and to explore effect modification by socioeconomic status (SES) and sex in the Madrid adult population. METHODS: A multilevel longitudinal design, based on a population-based retrospective cohort including 1,214,281 residents of Madrid (Spain) aged 40-75 years from 2015 to 2018. Outcomes were type 2 diabetes incidence and macrovascular (cardiac ischemia and/or stroke) and microvascular (chronic kidney disease, retinopathy, and/or peripheral vascular disease) complications in those with diabetes at baseline. Exercise facility availability was defined as the count of exercise facilities in a 1000 m street network buffer around each participant's residence. Poisson regression models with robust standard errors were used to estimate the risk ratios (RR). Interactions were explored with SES tertiles and by sex. RESULTS: Residents living in areas with lower exercise facility availability showed higher risk of type 2 diabetes (RRtertile3vs1 = 1.25, CI95% 1.21-1.30) as well as macrovascular (RRTertile3vs1 = 1.09 CI95% 1.00-1.19), and microvascular (RRTertile3vs1 = 1.10 CI95% 1.01-1.19) complications. Associations were strongest in low SES areas for type 2 diabetes (RRtertile3vs1-LOW-SES = 1.22, CI95% 1.12-1.32; RRtertile3vs1-HIGH-SES = 0.91, CI95% 0.85-0.98) and microvascular complications (RRtertile3vs1-LOW-SES = 1.12, CI95% 0,94-1,33; RRtertile3vs1-HIGH-SES = 0.88, CI95% 0.73-1.05). CONCLUSIONS: Living in areas with lower availability of exercise facilities was associated with a greater risk of type 2 diabetes and its complications. Increasing exercise opportunities, particularly in low SES areas, could help reduce the social gradient of diabetes and its complications.

Load and muscle group size influence the ergogenic effect of acute caffeine intake in muscular strength, power and endurance.

INTRODUCTION: Although acute caffeine intake seems to improve muscular strength-power-endurance performance, there is scarce evidence evaluating upper vs lower-body exercises at different loads. Thus, this study aimed to examine the effects of acute caffeine intake on upper and lower-body muscular strength, power and endurance performance at different loads. METHODS: Twenty resistance-trained athletes (male/female: 10/10; age: 23 ± 4 years; body mass: 70.6 ± 15.1) participated in a double-blind, placebo-controlled, cross-over and randomized study. Participants were provided with either 3 mg/kg of body mass of caffeine or maltodextrin (placebo). Sixty minutes after ingestion, they performed muscular strength and power assessment for bench press and back squat exercise at 25%, 50%, 75% and 90% 1-repetition-maximum (1RM), performing 3, 2, 1 and 1 repetitions respectively, followed by muscular endurance assessment for both exercises at 65% and 85% 1RM performing until task failure. Isometric handgrip, isometric mid-thigh pull and vertical jump tests were also performed. RESULTS: In muscular strength and power, compared to placebo, caffeine improved mean velocity (P = 0.045; pη2 = 0.101), mean power (P = 0.049; pη2 = 0.189) and rate of force development (RFD, P = 0.032; pη2 = 0.216), particularly in back squat exercise at 75% and 90% 1RM where mean velocity increased by 5-7% (P = 0.48-0.038; g = 0.348-1.413), mean power by 6-8% (P = 0.050-0.032; g = 0.547-0.818) and RFD by 17-97% (P = 0.042-0.046; g = 1.436-1.196). No differences were found in bench press exercise. In muscular endurance, caffeine improved the number of repetitions in all exercises and loads (P = 0.003; pη2 = 0.206), but only in back squat exercise at 85% 1RM, caffeine increased mean and peak velocity (8-9%, P = 0.006-0.004; g = 2.029-2.075), mean and peak power (10-13%, P = 0.006-0.003; g = 0.888-1.151) and force peak (3%, P = 0.009; g = 0.247). CONCLUSIONS: Acute caffeine intake (3 mg/kg) improved muscular strength, power and endurance performance, revealing a more pronounced effect at high-loads (≥ 75% 1RM) and in lower-body (back squat) than in upper-body exercise (bench press) according to muscle group size.

Impact of time-of-day and chronotype on neuromuscular performance in semi-professional female volleyball players.

This study aimed to determine if time-of-day could influence physical volleyball performance in females and to explore the relationship between chronotype and volleyball-specific performance. Fifteen young female athletes participated in a randomized counterbalanced trial, performing a neuromuscular test battery in the morning (9:00 h) and the evening (19:00 h) that consisted of volleyball standing spike, straight leg raise, dynamic balance, vertical jump, modified agility T-test and isometric handgrip tests. Chronotype was determined by the morningness-eveningness questionnaire. Compared to the morning, an increased performance was found in the standing spike (4.5%, p = .002, ES = 0.59), straight leg raise test (dominant-limb) (6.5%, p = .012, ES = 0.40), dynamic balance (non-dominant-limb) (5.0%, p = .010, ES = 0.57) and modified T-test (2.1%, p = .049, ES = 0.45) performance in the evening; while no statistical differences were reported in vertical jump tests or isometric handgrip strength. Moreover, no associations were found between chronotype and neuromuscular performance (r = -0.368-0.435, p = .052-0.439). Time-of-day affected spike ball velocity, flexibility in the dominant-limb, dynamic balance in the non-dominant-limb and agility tests. However, no association was reported among these improvements and the chronotype. Therefore, although the chronotype may not play critical role in volleyball-specific performance, evening training/matches schedules could benefit performance in semi-professional female volleyball players.

Exercise facilities and the prevalence of obesity and type 2 diabetes in the city of Madrid.

AIMS/HYPOTHESIS: We aimed to study the association between the availability of exercise facilities and the likelihood of obesity and type 2 diabetes in the adult population of Madrid, Spain. METHODS: We analysed the electronic medical records of all 1,270,512 residents of Madrid aged 40-75 years in 2017. Exercise facility availability was defined as the count of exercise facilities in a 1000 m street network buffer around each residential building entrance. Poisson regression with standard errors clustered at census tract level was used to assess prevalence ratios of exercise facility availability tertiles and obesity and type 2 diabetes. We also examined stratified results by tertiles of area-level socioeconomic status (SES) and sex. RESULTS: People living in areas with lower availability of exercise facilities had a higher prevalence of obesity (prevalence ratio [PR] 1.22 [95% CI 1.20, 1.25]) and diabetes (PR 1.38 [95% CI 1.34, 1.43]). We observed effect modification by area-level SES (p<0.001), with stronger associations for residents living in low-SES areas and no association for residents living in high-SES areas. Associations with type 2 diabetes were stronger among women compared with men, while associations with obesity were similar by sex. CONCLUSIONS/INTERPRETATION: People living in areas with low availability of exercise facilities had a higher prevalence of obesity and type 2 diabetes, and this association was strongest in low-SES areas and for women. Understanding the potential role of exercise facilities in driving inequities in obesity and type 2 diabetes prevalence may inform interventions to reduce health inequities.

Circulating myokines IL-6, IL-15 and FGF21 response to training is altered by exercise type but not by menopause in women with obesity.

To examine the effects of a time-matched endurance vs. concurrent training on circulating IL-6, IL-13, IL-15, IL-15Ra, FGF21 levels in postmenopausal women with obesity, and to determine these myokines response to endurance training pre- and postmenopause. Thirty-five sedentary postmenopausal women with obesity were randomly divided into endurance training (EN1, N = 10), concurrent training (CON, N = 13) or no training group (CT, N = 12). Additionally, twelve sedentary premenopausal women with obesity were added to an endurance training group (EN2, N = 12). Participants took part in a 12-week supervised intervention, performing 3 sessions/week of 60 min/session. Before and after the interventions, body composition and fitness were assessed, and blood samples obtained to measure serum myokines levels. Total fat mass decreased in all exercised groups (CON,-5.2%; EN1,-5.3%; EN2,-5.6%). In postmenopausal women, serum IL-6, IL-15 and IL-15Ra decreased after training (P<0.01), finding a pronounced reduction in IL-6 (-42% vs. -16%) and IL-15 (-50% vs. -31%) when comparing EN1 to CON (P<0.05). Serum FGF21 was only reduced in the EN1 (-27%; P=0.012). While EN1 and EN2 comparison, reported differences for IL-15Rα concentration (-28% vs. -40%; P=0.023). Finally, in EN2, the delta change of fat mass and IL-6, IL-15 and IL-15Rα were associated (r = 0.605; r = 0.546; r = 0.515; P<0.05). IL-13 showed undetected concentrations. Circulating IL-6, IL-15 and FGF21 response to training is altered by exercise type but not by menopause in women with obesity. Endurance training promotes a higher reduction of these myokines, potentially activating their intricate immune and fat mass regulation roles in postmenopausal women with obesity.

The Role of Exercise Training on Low-Grade Systemic Inflammation in Adults with Overweight and Obesity: A Systematic Review.

Low-grade systemic inflammation leads to critical alterations of several tissues and organs that can promote the appearance of non-communicable diseases, a risk that is increased in adults with obesity. Exercise training may counteract low-grade systemic inflammation, but there is a lack of consensus on how cytokines are modulated by training in adults with obesity. This study aimed of examining the effects of exercise training on circulating pro- and anti-inflammatory cytokines in adults with overweight and obesity, and whether exercise-induced fat mass reduction could mediate that effect. The search was conducted on Medline (Pubmed), SPORTDiscus and Web of Science databases from January 1998 to August 2021, using keywords pertaining to inflammation, exercise, and obesity. A total of 27 studies were selected, in which the circulating concentration levels of cytokines were analyzed. Endurance training (ET) decreased circulating CRP, IL-6 and TNF-α levels. TNF-α was reduced after resistance and concurrent training (CT), while IL-10 increased after resistance training (RT). Changes in IL-10 and CRP coincided with fat mass reduction, while decreased TNF-α levels were concomitant with changes in IL-6 and IL-10. Exercise training may reduce systemic low-grade inflammation profile in adults with overweight and obesity.

Dose-response effects of aerobic exercise on adiposity markers in postmenopausal women: pooled analyses from two randomized controlled trials.

BACKGROUND/OBJECTIVE: Exercise may reduce the risk of breast cancer through adiposity changes, but the dose-response effects of exercise volume on adiposity markers are unknown in postmenopausal women. We aimed to compare the dose-response effects of prescribed aerobic exercise volume on adiposity outcomes. PARTICIPANTS/METHODS: Data from the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were pooled for this analysis (N = 720). These were 12-month randomized controlled trials, where participants were randomized to 225 min/week (mid-volume) of aerobic exercise versus usual inactive lifestyle (ALPHA), or 150 min/week (low-volume) versus 300 min/week (high-volume) (BETA). Fat mass and fat-free mass were measured using DXA and intra-abdominal and subcutaneous fat area were assessed with computed tomography. RESULTS: After 12 months of aerobic exercise, increasing exercise volumes from no exercise/control to 300 min/week resulted in statistically significant reductions in BMI, weight, fat mass, fat percentage, intra-abdominal and subcutaneous fat area (P < 0.001). Compared with controls, fat mass loss was -1.13, -1.98 and -2.09 kg in the low-, mid- and high-volume groups, respectively. Similarly, weight loss was -1.47, -1.83, -2.21 kg in the low-, mid- and high-volume groups, respectively, compared to controls, and intra-abdominal fat area loss was -7.44, -15.56 and -8.76 cm2 in the low-, mid- and high-volume groups, respectively, compared to controls. No evidence for a dose-response effect on fat-free mass was noted. CONCLUSION: A dose-response effect of exercise volume on adiposity markers was noted, however, the differences in adiposity markers were smaller when comparing 225 min/week to 300 min/week of exercise. Given the strong positive associations between obesity and postmenopausal breast cancer risk, this study provides evidence on the importance of exercise volume as part of the exercise prescription to reduce adiposity and, ultimately, postmenopausal breast cancer risk.

Weight Regain and Breast Cancer-Related Biomarkers Following an Exercise Intervention in Postmenopausal Women.

BACKGROUND: Epidemiologic studies have reported associations between weight fluctuations and postmenopausal breast cancer risk; however, the biological markers involved in this association are unknown. This study aimed to explore the associations between breast cancer-related biomarkers and weight regain following exercise-induced weight loss. METHODS: From the 400 participants included in the Breast Cancer and Exercise Trial in Alberta, a total of 214 lost weight during the intervention and had follow-up blood samples, body composition, and covariate measurements. Outcomes were measured at baseline, 12 months (end of the study), and 24 months (follow-up). RESULTS: During follow-up, weight regain was 1.80 kg [95% confidence interval (CI): -0.40-3.90], and was significantly associated with increases in estradiol [treatment effect ratio (TER) = 1.03; 95% CI, 1.01-1.04], estrone (TER = 1.02; 95% CI, 1.01-1.03), free estradiol (TER = 1.04; 95% CI, 1.02-1.05), the homeostatic model assessment for insulin resistance (TER = 1.03; 95% CI, 1.02-1.05), and insulin (TER = 1.03; 95% CI, 1.01-1.04), and decreases in sex hormone-binding globulin (SHBG; TER = 0.98; 95% CI, 0.97-0.99) levels. Nonstatistically significant associations were found for glucose and C-reactive protein. Furthermore, a statistically significant linear trend of increasing levels for all biomarkers, and decreasing SHBG, across weight regain categories was found. CONCLUSIONS: These results suggest that weight regain following exercise-induced weight loss is associated with breast cancer-related biomarker changes in postmenopausal women. IMPACT: These findings provide evidence to support the importance of developing effective strategies to prevent weight regain and, consequently, decrease postmenopausal breast cancer risk via changes in adiposity-related biomarkers.

Exercise type and fat mass loss regulate breast cancer-related sex hormones in obese and overweight postmenopausal women.

PURPOSE: The aim of the study was to examine the effects of a time-matched endurance versus concurrent training on circulating sex hormone levels and body composition in postmenopausal women. METHODS: Thirty-five sedentary and obese postmenopausal women were recruited and randomly divided into endurance training (EN, n = 10), concurrent training (CON, n = 13), or control group (C, n = 12). Participants took part in a 12-week supervised intervention, training 3 days/week and 60 min/session. Before and after the intervention, body composition was assessed, and blood samples were obtained to evaluate estradiol, testosterone, DHEA-S, and SHBG. RESULT: In response to training, a reduction in total fat mass was found (5.3%; P < 0.05), while an increase in lean body mass was observed in the CON group (1.5%; P < 0.05). There was a significant decrease in DHEA-S (- 13%), total (- 40%) and free testosterone (- 41%) in the EN group, while in the CON group, total (25%) and free testosterone (21%) increased significantly (P < 0.05). When participants were stratified according to fat mass loss (> or < 2 kg), a statistically significant increase in circulating SHBG (21%) and decrease in DHEA-S (- 13%) were found. CONCLUSION: The type of exercise and exercise-induced fat mass loss seem to modify the sex hormone profile in postmenopausal women that is an established risk factor of breast cancer. Thus, this study provides additional evidences to the intricated interaction among sex hormones, adipose tissue, and muscle mass in postmenopausal women.

Circulating adiponectin expression is elevated and associated with the IL-15/IL-15Rα complex in obese physically active humans.

BACKGROUND: Adiponectin is an adipokine with oxidative, anti-inflammatory and antiatherogenic effects in several peripheral tissues; however, circulating adiponectin expression is reduced in cardio-metabolic diseases. The aim of this study was to ascertain whether regular physical activity mediates circulating adiponectin concentrations at baseline in an obese population. METHODS: Two hundred and twenty-one obese participants were divided into 6 groups according to gender, physical activity (PA), and type 2 diabetes mellitus (T2DM) diagnosis: A and B) obese PA females (N.=28) and males (N.=33); C and D) obese non-PA females (N.=40) and males (N.=40); E and F) obese non-PA females (N.=40) and males (N.=40) with T2DM. Serum adiponectin, IL-15 and IL-15Rα, blood glucose/lipid profile, and body composition were measured. RESULTS: Circulating adiponectin increased in PA participants compared to non-PA (ANOVA, P=0.001), finding higher concentrations in females compared to males (P<0.001), particularly in the PA group (P=0.005). Serum adiponectin was associated with age (R2=0.068), body mass (R2=-0.108), waist circumference (WC) (R2=-0.122), LDL (R2=-0.045), triglycerides (R2=-0.043), and serum IL-15Rα (R2=-0.243), as well as fat mass in females (R2=0.098), and WC in males (R2=0.112). CONCLUSIONS: Circulating adiponectin increased in obese PA participants (≥180 min/week) compared to non-PA counterparts, indicating that physical activity may mediate baseline adiponectin levels irrespective of the fat mass regulatory effect. The inverse relationship found between serum adiponectin and IL-15Rα may support the regulative role of the IL-15/IL-15Rα complex on this adipokine at baseline.

Evolution of Game Demands From Young to Elite Players in Men's Volleyball.

PURPOSE: To assess the evolution of the volleyball's game demands throughout players' development in men's volleyball. METHODS: A total of 150 sets and 6.671 rallies were analyzed. The sample was composed of 30 sets each by under-14, under-16, under-19, national senior, and international senior teams (1.291, 1.318, 1.310, 1.372, and 1.380 rallies for each category, respectively). Sets included in the sample were stratified and then randomly selected. The variables studied included play time, rest time, rallies played, jumps, hits, types of ball contact, types of game interruptions, performance of the game phases, and performance of the actions. Student t and Mann Whitney U tests were used to analyze specific differences between categories. RESULTS: The results showed significant reductions in the play times of the rally (from 8.91 to 6.79 s) and the set (6 min 23 s to 4 min 30 s), significant increases in the rest times of the rally (19.64 to 26.53 s) and the set (13 min 44 s to 20 min 27 s), and a significant increase in the number of jumps per set (113.5 to 181.3). Significant improvements in the reception performance (1.57 to 2.45 out of 3), attack performance (2.13 to 2.67 out of 4), and side-out-phase success (48.4% to 69.6%) were found. Throughout the players' development, data show an increase in the speed, intensity, and efficacy of the side-out phase. CONCLUSIONS: The findings provide reference values to guide athletes' development and to monitor training and matches both physically and technically tactically.

Caffeinated energy drinks improve volleyball performance in elite female players.

PURPOSE: The objective of this study is to determine the effects of a caffeine-containing energy drink on female volleyball players' performance. METHODS: Thirteen elite female volleyball players ingested 3 mg·kg of caffeine with an energy drink or the same drink without caffeine (placebo drink) in a double-blind and randomized study. Then, participants performed the following: standing spike, jumping spike, spike jump, blocking jump, squat jump, countermovement jump, manual dynamometry, and the agility t-test. A simulated volleyball game was played, videotaped, and notated afterward. RESULTS: In comparison to the placebo drink, the ingestion of the caffeinated energy drink increased the ball velocity in the standing spike (19.2 ± 2.1 vs 19.7 ± 1.9 m·s, P = 0.023) and in the jumping spike (17.9 ± 2.2 vs 18.8 ± 2.2 m·s, P = 0.038) and the jump height in the squat jump (28.1 ± 3.2 vs 29.4 ± 3.6 cm, P = 0.028), countermovement jump (32.0 ± 4.6 vs 33.1 ± 4.5 cm, P = 0.018), spike jump (43.3 ± 4.7 vs 44.4 ± 5.0 cm, P = 0.025), and block jump (35.2 ± 5.1 vs 36.1 ± 5.1 cm, P = 0.044). Furthermore, the caffeinated energy drink decreased the time needed to complete the agility t-test (11.1 ± 0.5 vs 10.9 ± 0.3 s, P = 0.036). During the game, the volleyball actions categorized as successful were more frequent with the caffeinated energy drink (34% ± 9% vs 45% ± 9%, P < 0.001), whereas imprecise actions decreased (28% ± 7% vs 14% ± 9%, P < 0.001) when compared with the placebo drink. CONCLUSION: Commercially available energy drinks can significantly improve physical performance in female volleyball players. Increased physical performance led to improved accuracy during an actual volleyball match.

Physical actions and work-rest time in men's beach volleyball / Ações físicas e intervalo trabalho-descanso em voleibol de praia masculino / Acciones físicas y tiempos de trabajo-descanso en voley-playa masculino

The purpose of this study was to assess the ball contacts, jumps, hits, work time, and rest ratio in male beach volleyball players in relation to their tactical roles. The sample of this study included 6970 rallies played by 91 beach volleyball players, which corresponded to 179 sets of the 2008 Men's Beach Volleyball World Tour (FIVB). We analyzed: ball contacts, jumps, hits, work time, rest time, set (first, second or third), and player's tactical role (e.g., defense specialist, blocker, or no specialization). A significantly higher number of jumps were executed by blockers. No differences were found in the third set for any of the physical variables studied. This paper provides references about the physical demands (e.g., contacts, jumps, and hits for blockers and defense specialists) and temporal patterns of the beach volleyball game (i.e., work and rest time) for two-set matches and three-set matches...

"Ações físicas e intervalo trabalho-descanso em voleibol de praia masculino." O objetivo do presente estudo foi avaliar o número de contatos com a bola, saltos, ataques, tempo de trabalho e descanso em jogadores de voleibol de praia masculino em função da sua especialização. A amostra do estudo foi composta por 6970 rallies, jogados por 91 participantes, correspondendo a 179 sets do Beach Volleyball World Tour (FIVB) de 2008. As variáveis estudadas foram: contatos com a bola, saltos, ataques, tempo de trabalho, tempo de descanso, set (1º, 2º e 3º) e especialização do jogador (defensor especialista, bloqueador, ou não especializado). Um número significativo de saltos foi realizado pelos bloqueadores. Não foram encontradas diferenças significativas no 3º set para qualquer uma das variáveis estudadas. Este estudo apresenta valores de referência acerca das demandas físicas (contatos, saltos e ataques realizados por bloqueadores e defensores especialistas) e dos padrões temporais do jogo de voleibol de praia (tempo de trabalho e descanso) para jogos de dois e três sets...

"Acciones físicas y tiempos de trabajo-descanso en voley-playa masculino." El objetivo de este estudio fue medir el número de contactos con el balón, saltos, golpeos, el tiempo de trabajo y de descanso de jugadores de voley-playa masculino en función de su rol de juego. La muestra de estudio estuvo compuesta por 6970 jugadas realizadas por 91 jugadores participantes en 179 sets de la Beach Volleyball World Tour (FIVB) de la temporada 2008. Las variables registradas fueron contactos realizadas, saltos, golpeos, tiempo trabajo, tiempo de descanso, set (1º, 2º, o 3º), and función de juego (bloqueador, especialista en defensa, o universal). Un significativo mayor número de saltos fueron realizados por los bloqueadores. No se encontraron diferencias en el tercer en ninguna de las variables físicas estudiadas. Este trabajo presenta valores de referencias de las demandas físicas (balón, saltos, golpeos) y parámetros temporales (tiempo de trabajo y de descanso) del juego del voley-playa para partidos de dos sets y de tres sets...

Enhancing physical performance in male volleyball players with a caffeine-containing energy drink.

There are no scientific data about the effects of caffeine intake on volleyball performance. The aim of this study was to investigate the effect of a caffeine-containing energy drink to enhance physical performance in male volleyball players. A double-blind, placebo-controlled, randomized experimental design was used. In 2 different sessions separated by 1 wk, 15 college volleyball players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed volleyball-specific tests: standing spike test, maximal squat jump (SJ), maximal countermovement jump (CMJ), 15-s rebound jump test (15RJ), and agility T-test. Later, a simulated volleyball match was played and recorded. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased ball velocity in the spike test (73 ± 9 vs 75 ± 10 km/h, P < .05) and the mean jump height in SJ (31.1 ± 4.3 vs 32.7 ± 4.2 cm, P < .05), CMJ (35.9 ± 4.6 vs 37.7 ± 4.4 cm, P < .05), and 15RJ (29.0 ± 4.0 vs 30.5 ± 4.6 cm, P < .05). The time to complete the agility test was significantly reduced with the caffeinated energy drink (10.8 ± 0.7 vs 10.3 ± 0.4 s, P < .05). In addition, players performed successful volleyball actions more frequently (24.6% ± 14.3% vs 34.3% ± 16.5%, P < .05) with the ingestion of the caffeinated energy drink than with the placebo drink during the simulated game. A caffeine-containing energy drink, with a dose equivalent to 3 mg of caffeine per kg body mass, might be an effective ergogenic aid to improve physical performance and accuracy in male volleyball players.

Anthropometric, body composition and somatotype characteristics of elite female volleyball players from the highest Spanish league.

This study aimed to describe morphological characteristics of elite female volleyball players from the highest Spanish league, with special focus on differences by performance level and playing positions. Nearly all female players playing in the highest Spanish volleyball league during season 2003/2004 participated in this study (N=148 elite players, 92% of the total). Anthropometric, body composition and somatotype parameters according to performance and playing positions were analysed. The players' characteristics were as follows; body mass 72.3 ± 8.4 kg; stature 179.8 ± 7.1 cm; body fat 24.0 ± 3.1% and skeletal muscle mass 27.3 ± 2.9 kg. Mean somatotype was 3.1 ± 0.7; 3.4 ± 0.9; 3.1 ± 0.9 characterised as central with a tendency to balanced mesomorph. Top level players (whose teams were better classified in the team performance ranking) were taller, had higher skeletal muscle mass and ectomorphy, and had a lower level of adiposity markers, compared with lower level players. Players selected for their respective National teams (individual performance) were taller, heavier, had higher muscle mass and lower endomorphy than non-selected players. Differences according to playing positions were found. This study provides a complete set of reference data on anthropometry, body composition and somatotype of elite female volleyball players. Morphological differences have been identified according to performance level and playing position.

Anthropometric, physical, and age differences by the player position and the performance level in volleyball.

The purpose of this paper was to study the ranges in height, weight, age, spike reach, and block reach of volleyball players in relation to the player position and the level of their respective teams in peak performance. The analysed sample included 1454 male and 1452 female players who participated in the volleyball competitions of the Olympic Games and World Championships in the 2000-2012 period. A descriptive, correlational, and longitudinal design was used. The variables studied were: the player position, body height, weight, body mass index, spike reach, block reach, age, and team level. The results show differences between body height, spike and block reaches, and the age of the players by their position. These differences are related to the needs of the different positions with regard to the actions they execute. Middle-blockers, outside-hitters, and opposites have the characteristics that are most suitable for blocking and spiking, and the setters and liberos appear to have characteristics conducive to setting and receiving as well as digging, respectively. The differences found in the studied variables with regard to the playing position are related to players' needs regarding the actions they perform. Player's age was a variable that differentiated first teams at this level of competition for males, and physical capacities (body height, weight, spike reach, and block reach) were variables that differentiated first teams at this level of competition for females.

Match Duration and Number of Rallies in Men's and Women's 2000-2010 FIVB World Tour Beach Volleyball.

After the 2000 Olympic Games, the Fédération Internationale de Volleyball (FIVB) modified the scoring system used in beach volleyball from side-out to a rally point system. The goal was to facilitate the comprehension of the game and to stabilize match duration. The purpose of this study was to assess the duration and number of rallies in men's and women's beach volleyball matches (2000-2010 FIVB World Tour). Data from 14,432 men's matches and 14,175 women's matches of the 2000-2010 World Tour were collected. The variables studied were: match duration, total rallies per set and match, number of sets, team that won the set and match, type of match (equality in score), and gender. The average match duration in beach volleyball is stable, ranging from 30 to 64 minutes, regardless of the number of sets, the stage of the tournament (qualifying round or main draw), or gender. The average number of rallies per match were 78-80 for two-set matches and 94-96 for three-set matches. Matches from the main draw are more balanced than matches from the qualifying round. More balanced matches (smaller point difference between teams) have longer durations. It is not clear why there is no relationship between the number of rallies and match duration. Future studies are needed to clarify this aspect. The results can serve as a reference to guide beach volleyball training (with regard to duration and number of rallies) and to help understand the effect of the rule change.