Analysis of Dehydration and Strength in Elite Badminton Players

Background: The negative effects of dehydration on aerobic activities are well established. However, it is unknown how dehydration affects intermittent sports performance. The purpose of this study was to identify the level of dehydration in elite badminton players and its relation to muscle strength and power production. Methodology: Seventy matches from the National Spanish badminton championship were analyzed (46 men?s singles and 24 women?s singles). Before and after each match, jump height and power production were determined during a countermovement jump on a force platform. Participants? body weight and a urine sample were also obtained before and after each match. The amount of liquid that the players drank during the match was also calculated by weighing their individual drinking bottles. Results and Discussion: Sweat rate during the game was 1.1460.46 l/h in men and 1.0260.64 l/h in women. The players rehydrated at a rate of 1.1060.55 l/h and 1.0160.44 l/h in the male and female groups respectively. Thus, the dehydration attained during the game was only 0.3760.50% in men and 0.3260.83% in women. No differences were found in any of the parameters analyzed during the vertical jump (men: from 31.8265.29 to 32.9064.49 W/kg; p.0.05, women: from 26.3664.73 to 27.2564.44 W/kg; p.0.05). Post-exercise urine samples revealed proteinuria (60.9% of cases in men and 66.7% in women), leukocyturia (men = 43.5% and women = 50.0%) and erythrocyturia (men = 50.0% and women = 21.7%). Conclusions: Despite a moderate sweat rate, badminton players adequately hydrated during a game and thus the dehydration attained was low. The badminton match did not cause muscle fatigue but it significantly increased the prevalence of proteinuria, leukocyturia and erythrocyturia

Effects of a Caffeine-Containing Energy Drink on Simulated Soccer Performance

[Background] To investigate the effects of a caffeine-containing energy drink on soccer performance during a simulated game. A second purpose was to assess the post-exercise urine caffeine concentration derived from the energy drink intake. [Methodology/Principal Findings] Nineteen semiprofessional soccer players ingested 630±52 mL of a commercially available energy drink (sugar-free Red Bull®) to provide 3 mg of caffeine per kg of body mass, or a decaffeinated control drink (0 mg/kg). After sixty minutes they performed a 15-s maximal jump test, a repeated sprint test (7×30 m; 30 s of active recovery) and played a simulated soccer game. Individual running distance and speed during the game were measured using global positioning satellite (GPS) devices. In comparison to the control drink, the ingestion of the energy drink increased mean jump height in the jump test (34.7±4.7 v 35.8±5.5 cm; P<0.05), mean running speed during the sprint test (25.6±2.1 v 26.3±1.8 km · h−1; P<0.05) and total distance covered at a speed higher than 13 km · h−1 during the game (1205±289 v 1436±326 m; P<0.05). In addition, the energy drink increased the number of sprints during the whole game (30±10 v 24±8; P<0.05). Post-exercise urine caffeine concentration was higher after the energy drink than after the control drink (4.1±1.0 v 0.1±0.1 µg · mL−1; P<0.05). [Conclusions/significance] A caffeine-containing energy drink in a dose equivalent to 3 mg/kg increased the ability to repeatedly sprint and the distance covered at high intensity during a simulated soccer game. In addition, the caffeinated energy drink increased jump height which may represent a meaningful improvement for headers or when players are competing for a ball

Asymmetric response of forest and grassy biomes to climate variability across the African Humid Period : influenced by anthropogenic disturbance?

A comprehensive understanding of the relationship between land cover, climate change and disturbance dynamics is needed to inform scenarios of vegetation change on the African continent. Although significant advances have been made, large uncertainties exist in projections of future biodiversity and ecosystem change for the world's largest tropical landmass. To better illustrate the effects of climate–disturbance–ecosystem interactions on continental‐scale vegetation change, we apply a novel statistical multivariate envelope approach to subfossil pollen data and climate model outputs (TraCE‐21ka). We target paleoenvironmental records across continental Africa, from the African Humid Period (AHP: ca 14 700–5500 yr BP) – an interval of spatially and temporally variable hydroclimatic conditions – until recent times, to improve our understanding of overarching vegetation trends and to compare changes between forest and grassy biomes (savanna and grassland). Our results suggest that although climate variability was the dominant driver of change, forest and grassy biomes responded asymmetrically: 1) the climatic envelope of grassy biomes expanded, or persisted in increasingly diverse climatic conditions, during the second half of the AHP whilst that of forest did not; 2) forest retreat occurred much more slowly during the mid to late Holocene compared to the early AHP forest expansion; and 3) as forest and grassy biomes diverged during the second half of the AHP, their ecological relationship (envelope overlap) fundamentally changed. Based on these asymmetries and associated changes in human land use, we propose and discuss three hypotheses about the influence of anthropogenic disturbance on continental‐scale vegetation change

Distribution of Diatoms in the Baza Lacustrine system, SE, Spain

Several outcrops with diatoms have been identified in the Neogene-Quaternary Baza basin. The most relevant two are located in the NE margin, in different lithostratigraphic units. Their diatom flora is dominated by Epithemia adnata and Epithemia turgida, a littoral epiphytic aquatic plants. These diatom assemblages are typical of fresh to slightly brackish waters in shallow and alkaline lakes. Those two diatomitic deposits are interstratified between alluvial sediments and represent permanent shallow lakes developed during two wet periods of time. Barranco de las Lumbres is the oldest of these lake events and is dated by fauna and paleomagnetism as late Miocene (Turolian). The upper beds of the younger lake episode (Rincon de la Losa) is dated by paleomagnetism and mammals at 1.9 Ma. In addition to these marginal diatomitic deposits, other outcrops with diatoms have been identified in more central areas of the Basin in Galera village, the lower part of Barranco del Agua section is composed of gypsum, carbonates and dark-brown clays and marls. Here epiphytic shallow-water diatoms Epithemia adnata, Epithemia turgida and some planktonic littoral forms (Fragilaria sp.) suggest a shallow fresh to oligosaline water environment. Additional diatomaceous deposits were located in a more evaporitic zone of the basin near the town of Castillejar. This outcrop presents species (Navicula digitoradiata and Surirella ovalis), which indicate distinctive more saline waters and environment. The distribution of the diatom flora in the Baza basin is consistent with stratigraphic data, which indicates an increase of evaporitic facies towards the center of the basin and the occurrence of different kinds of waters within the lake system. The isotopic composition (δ34S, δ18O) of the gypsum samples of Baza basin (Gibert et al., 2007a) is consistent with a Triassic origin of the sulphate as a result of chemical recycling. These data also suggest that a similar recycling mechanism operated in the saline lake system, where the gypsum sediments from the margins were coevally recycled towards the inner part

Distribution of Diatoms in the Baza Lacustrine system, SE, Spain

Several outcrops with diatoms have been identified in the Neogene-Quaternary Baza basin. The most relevant two are located in the NE margin, in different lithostratigraphic units. Their diatom flora is dominated by Epithemia adnata and Epithemia turgida, a littoral epiphytic aquatic plants. These diatom assemblages are typical of fresh to slightly brackish waters in shallow and alkaline lakes. Those two diatomitic deposits are interstratified between alluvial sediments and represent permanent shallow lakes developed during two wet periods of time. Barranco de las Lumbres is the oldest of these lake events and is dated by fauna and paleomagnetism as late Miocene (Turolian). The upper beds of the younger lake episode (Rincon de la Losa) is dated by paleomagnetism and mammals at 1.9 Ma. In addition to these marginal diatomitic deposits, other outcrops with diatoms have been identified in more central areas of the Basin in Galera village, the lower part of Barranco del Agua section is composed of gypsum, carbonates and dark-brown clays and marls. Here epiphytic shallow-water diatoms Epithemia adnata, Epithemia turgida and some planktonic littoral forms (Fragilaria sp.) suggest a shallow fresh to oligosaline water environment. Additional diatomaceous deposits were located in a more evaporitic zone of the basin near the town of Castillejar. This outcrop presents species (Navicula digitoradiata and Surirella ovalis), which indicate distinctive more saline waters and environment. The distribution of the diatom flora in the Baza basin is consistent with stratigraphic data, which indicates an increase of evaporitic facies towards the center of the basin and the occurrence of different kinds of waters within the lake system. The isotopic composition (δ34S, δ18O) of the gypsum samples of Baza basin (Gibert et al., 2007a) is consistent with a Triassic origin of the sulphate as a result of chemical recycling. These data also suggest that a similar recycling mechanism operated in the saline lake system, where the gypsum sediments from the margins were coevally recycled towards the inner part