Deep history of cultural and linguistic evolution among Central African hunter-gatherers.

Human evolutionary history in Central Africa reflects a deep history of population connectivity. However, Central African hunter-gatherers (CAHGs) currently speak languages acquired from their neighbouring farmers. Hence it remains unclear which aspects of CAHG cultural diversity results from long-term evolution preceding agriculture and which reflect borrowing from farmers. On the basis of musical instruments, foraging tools, specialized vocabulary and genome-wide data from ten CAHG populations, we reveal evidence of large-scale cultural interconnectivity among CAHGs before and after the Bantu expansion. We also show that the distribution of hunter-gatherer musical instruments correlates with the oldest genomic segments in our sample predating farming. Music-related words are widely shared between western and eastern groups and likely precede the borrowing of Bantu languages. In contrast, subsistence tools are less frequently exchanged and may result from adaptation to local ecologies. We conclude that CAHG material culture and specialized lexicon reflect a long evolutionary history in Central Africa.

Drink then drive away: The effects of lowering the blood alcohol concentration in Utah.

In March of 2017 Utah announced its intent to lower the legal blood alcohol content (BAC) for driving from 0.08 to 0.05 g/dL. However, this change did not take effect until 2019. We employ a difference-in- differences strategy on Utah counties using neighboring states as controls to test whether this policy change significantly affected the number of traffic accidents or the severity of those accidents. Results show the policy appears to temporarily decrease the total number of accidents, limited primarily to property damage- only accidents. We believe these results may be partially explained by drivers who, after the policy is enacted, avoid reporting property damage-only accidents if possible. Using insurance claims data, we show there is no corresponding fall in insurance claims or payouts suggesting that the fall in total accidents likely comes from under-reporting.

The genetic legacy of the Manila galleon trade in Mexico.

The population of Mexico has a considerable genetic substructure due to both its pre-Columbian diversity and due to genetic admixture from post-Columbian trans-oceanic migrations. The latter primarily originated in Europe and Africa, but also, to a lesser extent, in Asia. We analyze previously understudied genetic connections between Asia and Mexico to infer the timing and source of this genetic ancestry in Mexico. We identify the predominant origin within Southeast Asia-specifically western Indonesian and non-Negrito Filipino sources-and we date its arrival in Mexico to approximately 13 generations ago (1620 CE). This points to a genetic legacy from the seventeenth century Manila galleon trade between the colonial Spanish Philippines and the Pacific port of Acapulco. Indeed, within Mexico we observe the highest level of this trans-Pacific ancestry in Acapulco, located in the state of Guerrero. This colonial Spanish trade route from East Asia to Europe was centred on Mexico and appears in historical records, but its legacy has been largely ignored. Identities and stories were suppressed due to slavery, assimilation of the immigrants as 'Indios' and incomplete historical records. Here we characterize this understudied Mexican ancestry. This article is part of the theme issue 'Celebrating 50 years since Lewontin's apportionment of human diversity'.

Influence of Secondary School Students' Physical Fitness on Sports Performance during an Ultimate Frisbee Competition.

The aim of the present study was to investigate the effect of secondary school students' fitness profile on physical and technical−tactical performance in simulated competition conditions of ultimate frisbee when there is no previous experience in the practice of the sport. Forty-three secondary school students participated in this research. The students were divided into two groups according to their results in the Assessing Levels of Physical Activity and fitness test battery (ALPHA fitness test): poor physical fitness (PPF) (N = 24; age: 14.9 ± 0.8 years; height: 166.1 ± 10.9 cm; body mass: 62.2 ± 11.0 kg; ALPHA fitness score: 2.7 ± 0.7 points) and good physical fitness (GPF) (N = 19; age: 14.5 ± 0.6 years; height: 165.9 ± 5.8 cm; body mass: 58.9 ± 7.5 kg; ALPHA fitness score: 4.4 ± 0.3 points). Physical variables during the ultimate frisbee match were assessed using Global Positioning System technology. The matches were video-recorded, and individual technical actions were noted afterwards. The GPF group showed higher values for running (p = 0.039), high-speed running (p = 0.015), sprinting (p = 0.022) and total distance covered (p = 0.025) than the PPF group. In addition, more passes (p = 0.019), offensive decision making (p = 0.009) and player participation (p = 0.046) were recorded in the GPF group than the PPF group. Correlational analysis revealed a positive relationship (p < 0.05) between individual participation and the meters covered for jogging, running, running at high speed and sprinting during the game. In conclusion, although the students were novices in ultimate frisbee, the high physical fitness level had a positive effect on the game performance. Physical education teachers should consider this information when introducing new sports into their physical education classes.

Paths and timings of the peopling of Polynesia inferred from genomic networks.

Polynesia was settled in a series of extraordinary voyages across an ocean spanning one third of the Earth1, but the sequences of islands settled remain unknown and their timings disputed. Currently, several centuries separate the dates suggested by different archaeological surveys2-4. Here, using genome-wide data from merely 430 modern individuals from 21 key Pacific island populations and novel ancestry-specific computational analyses, we unravel the detailed genetic history of this vast, dispersed island network. Our reconstruction of the branching Polynesian migration sequence reveals a serial founder expansion, characterized by directional loss of variants, that originated in Samoa and spread first through the Cook Islands (Rarotonga), then to the Society (Totaiete ma) Islands (11th century), the western Austral (Tuha'a Pae) Islands and Tuamotu Archipelago (12th century), and finally to the widely separated, but genetically connected, megalithic statue-building cultures of the Marquesas (Te Henua 'Enana) Islands in the north, Raivavae in the south, and Easter Island (Rapa Nui), the easternmost of the Polynesian islands, settled in approximately AD 1200 via Mangareva.

An international perspective for 'Improving teacher professional development for online and blended learning: a systematic meta-aggregative review'.

This paper is in response, from an international perspective, to the manuscript entitled "Improving teacher professional development for online and blended learning: a systematic meta-aggregative review" (Philipsen, B., Tondeur, J., Pareja Roblin, N. et al. 2019). The impact of the manuscript has been reinforced by the claims of international organisations like UNESCO and ILO, as far as they highlight that Teacher Professional Development (TPD) for Online and Blended Learning are a priority in the present scenario. The findings can be clearly applied to guide appropriated TPD for the recovery as well as for a resilient education system. Nevertheless, the research was conducted in a West-European context where most learners use computers on an everyday basis, while half the world's students do not have access to a household computer, and this has determined the emergency response to the pandemic. Dreesen et al. (2020) reported that most of the countries have adopted a remote education based on some combination of digital platforms, television, radio, take-home packages, home visits, text messaging and phone calls. It would be very interesting to incorporate these recent discoveries in the use of frugal technologies and elucidate if new components should be aggregated for TPD strategies from an international perspective. As far as the authors adopted the approach of a systematic meta-aggregative review, new data supported by unequivocal or credible evidence can be conveniently incorporated without reinterpreting the original findings.

Native American gene flow into Polynesia predating Easter Island settlement.

The possibility of voyaging contact between prehistoric Polynesian and Native American populations has long intrigued researchers. Proponents have pointed to the existence of New World crops, such as the sweet potato and bottle gourd, in the Polynesian archaeological record, but nowhere else outside the pre-Columbian Americas1-6, while critics have argued that these botanical dispersals need not have been human mediated7. The Norwegian explorer Thor Heyerdahl controversially suggested that prehistoric South American populations had an important role in the settlement of east Polynesia and particularly of Easter Island (Rapa Nui)2. Several limited molecular genetic studies have reached opposing conclusions, and the possibility continues to be as hotly contested today as it was when first suggested8-12. Here we analyse genome-wide variation in individuals from islands across Polynesia for signs of Native American admixture, analysing 807 individuals from 17 island populations and 15 Pacific coast Native American groups. We find conclusive evidence for prehistoric contact of Polynesian individuals with Native American individuals (around AD 1200) contemporaneous with the settlement of remote Oceania13-15. Our analyses suggest strongly that a single contact event occurred in eastern Polynesia, before the settlement of Rapa Nui, between Polynesian individuals and a Native American group most closely related to the indigenous inhabitants of present-day Colombia.

Effects of muscular injuries on the technical and physical performance of professional soccer players.

Introduction: The aim of this study was to determine the effects of muscular injuries in the lower limbs on the technical and physical performance of professional soccer players when they return to the league competition. Methods: Seventy-six muscular injuries incurred by Spanish male professional soccer players (Age: 27.5 ± 3.5 years) were analyzed during two consecutive competitive seasons: 2014-2015 and 2015-2016. The players' performance was studied during Spanish First Division competitive matches using a multi-camera computerized tracking system (Mediacoach Desktop). Results: After muscular injury relative total distance covered in sprints decreased by 8.6 ± 30.2% (P = 0.013) in the first half and 7.7 ± 36.6% (P = 0.038) in the second half. Similarly, maximal running speed decreased by 2.78 ± 6.91 km.h-1 (pre: 27.3 ± 6.4 km.h-1vs. post: 24.5 ± 6.6 km.h-1, P = 0.013) in the first half, and 1.50 ± 5.68 km.h-1 (29.1 ± 3.9 km.h-1vs. 27.6 ± 5.3 km.h-1, P = 0.043) in the second half. Muscle injury also affected technical performance significantly decreasing successful passes (P = 0.045). There were no differences in the number of possession gains (P = 0.277), and possession losses (P = 0.178). Conclusions: After a moderate or severe muscular injury (causing >8 days lay off), player performance is significantly lower in high-intensity efforts and technical skills such as sprints, maximal running speed, or successful passes.

Effects of Caffeine Ingestion on Skill Performance During an International Female Rugby Sevens Competition.

Portillo, J, Del Coso, J, and Abián-Vicén, J. Effects of caffeine ingestion on skill performance during an international female rugby sevens competition. J Strength Cond Res 31(12): 3351-3357, 2017-The aim of this study was to establish the effects of a caffeine-containing energy drink on skills and technical performance during a match in female elite rugby sevens players. On 2 nonconsecutive days of a friendly tournament, 16 women from the Spanish national rugby sevens team (mean age = 23 ± 2 years) ingested 3 mg of caffeine per kilogram of body mass in the form of an energy drink or the same drink without caffeine (placebo drink). After 60 minutes for caffeine absorption, participants played 3 rugby sevens matches against another national team. Body impacts during the matches were assessed by triaxial accelerometers. The matches were videotaped, and each individual technical action was notated afterward by 2 experienced observers. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased the rate of body impacts in zone 1 (16.1 ± 4.9 vs. 20.8 ± 9.9 impacts/min, p < 0.05), zone 2 (12.2 ± 10.6 vs. 16.2 ± 15.2 impacts/min, p < 0.05), zone 3 (3.8 ± 1.5 vs. 4.7 ± 2.6 impacts/min, p < 0.05), and zone 5 (0.8 ± 0.4 vs. 1.1 ± 0.6 impacts/min, p < 0.05). The pre-exercise ingestion of the caffeinated energy drink did not affect the frequency or the quality of any rugby-specific technical actions during the games. In conclusion, the ingestion of 3 mg·kg of caffeine in the form of an energy drink increased the number of body impacts during a rugby sevens international competition which suggests a higher engagement of the players during the game. However, the caffeine ingestion did not influence the quality of the technical actions performed during the competition.

Caffeinated Energy Drinks Improve High-Speed Running in Elite Field Hockey Players.

The aim of this investigation was to determine the efficacy of a caffeine-containing energy drink to improve physical performance of elite field hockey players during a game. On 2 days separated by a week, 13 elite field hockey players (age and body mass = 23.2 ± 3.9 years and 76.1 ± 6.1 kg) ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo drink). After 60 min for caffeine absorption, participants played a simulated field hockey game (2 × 25 min). Individual running pace and instantaneous speed during the game were assessed using GPS devices. The total number of accelerations and decelerations was determined by accelerometry. Compared with the placebo drink, the caffeinated energy drink did not modify the total distance covered during the game (6,035 ± 451 m and 6,055 ± 499 m, respectively; p = .87), average heart rate (155 ± 13 beats per min and 158 ± 18 beats per min, respectively; p = .46), or the number of accelerations and decelerations (697 ± 285 and 618 ± 221, respectively; p = .15). However, the caffeinated energy drink reduced the distance covered at moderate-intensity running (793 ± 135 and 712 ± 116, respectively; p = .03) and increased the distance covered at high-intensity running (303 ± 67 m and 358 ± 117 m; p = .05) and sprinting (85 ± 41 m and 117 ± 55 m, respectively; p = .02). Elite field hockey players can benefit from ingesting caffeinated energy drinks because they increase the running distance covered at high-intensity running and sprinting. Increased running distance at high speed might represent a meaningful advantage for field hockey performance.

Enhancement of High-Intensity Actions and Physical Performance During a Simulated Brazilian Jiu-Jitsu Competition With a Moderate Dose of Caffeine.

CONTEXT: Although caffeine is one of the most commonly used substances in combat sports, information about its ergogenic effects on these disciplines is very limited. PURPOSE: To determine the effectiveness of ingesting a moderate dose of caffeine to enhance overall performance during a simulated Brazilian jiu-jitsu (BJJ) competition. METHODS: Fourteen elite BJJ athletes participated in a double-blind, placebo-controlled experimental design. In a random order, the athletes ingested either 3 mg/kg body mass of caffeine or a placebo (cellulose, 0 mg/kg) and performed 2 simulated BJJ combats (with 20 min rest between them), following official BJJ rules. Specific physical tests such as maximal handgrip dynamometry, maximal height during a countermovement jump, permanence during a maximal static-lift test, peak power in a bench-press exercise, and blood lactate concentration were measured at 3 specific times: before the first combat and immediately after the first and second combats. The combats were video-recorded to analyze fight actions. RESULTS: After the caffeine ingestion, participants spent more time in offensive actions in both combats and revealed higher blood lactate values (P < .05). Performance in all physical tests carried out before the first combat was enhanced with caffeine (P < .05), and some improvements remained after the first combat (eg, maximal static-lift test and bench-press exercise; P < .05). After the second combat, the values in all physical tests were similar between caffeine and placebo. CONCLUSIONS: Caffeine might be an effective ergogenic aid for improving intensity and physical performance during successive elite BJJ combats.

Enhancing physical performance in elite junior tennis players with a caffeinated energy drink.

The aim of this study was to investigate the effectiveness of a caffeinated energy drink to enhance physical performance in elite junior tennis players. In 2 different sessions separated by 1 wk, 14 young (16 ± 1 y) elite-level tennis players ingested 3 mg caffeine per kg body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed a handgrip-strength test, a maximal-velocity serving test, and an 8 × 15-m sprint test and then played a simulated singles match (best of 3 sets). Instantaneous running speed during the matches was assessed using global positioning (GPS) devices. Furthermore, the matches were videotaped and notated afterward. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased handgrip force by ~4.2% ± 7.2% (P = .03) in both hands, the running pace at high intensity (46.7 ± 28.5 vs 63.3 ± 27.7 m/h, P = .02), and the number of sprints (12.1 ± 1.7 vs 13.2 ± 1.7, P = .05) during the simulated match. There was a tendency for increased maximal running velocity during the sprint test (22.3 ± 2.0 vs 22.9 ± 2.1 km/h, P = .07) and higher percentage of points won on service with the caffeinated energy drink (49.7% ± 9.8% vs 56.4% ± 10.0%, P = .07) in comparison with the placebo drink. The energy drink did not improve ball velocity during the serving test (42.6 ± 4.8 vs 42.7 ± 5.0 m/s, P = .49). The preexercise ingestion of caffeinated energy drinks was effective to enhance some aspects of physical performance of elite junior tennis players.

Development and psychometric properties of the resistance to trauma test (TRAUMA) / Desarrollo y propiedades psicométricas del Test de Resistencia al trauma (TRauma)

BACKGROUND: The Resistance to trauma Test: TRauma is an instrument designed to assess six dimensions involving personal strengths or resources that promote coping with difficult life situations. In addition, an overall score is obtained that is conceptually equivalent to the concept of resilience. The aim of this study was to analyze the psychometric properties and factorial structure of the TRauma in a sample of subjects affected by a traumatic event. METHOD: Participants were 222 people affected by a traumatic life event (36.5% males), with ages ranging between 18 and 71 years. RESULTS: Confirmatory factor analysis supports the theoretical internal structure proposed for the instrument. Moreover, the reliability coefficients of the six scales and the total score are both acceptable. CONCLUSIONS: Overall, the findings of this study support the use of the TRauma to measure factors of personal strengths and resilience. However, these results do not exhaust the validation process of the TRauma, and it is necessary to continue to seek empirical evidence

ANTECEDENTES: el «Test de Resistencia al trauma: TRauma» es un instrumento que pretende evaluar seis dimensiones que suponen fortalezas o recursos personales que favorecen el afrontamiento de situaciones vitales difíciles. También se obtiene una puntuación global que sería conceptualmente equivalente al concepto de resiliencia. El objetivo de este estudio es analizar las propiedades psicométricas y la estructura factorial del TRauma en una muestra de sujetos afectados por algún suceso traumático. MÉTODO: los participantes fueron 222 personas afectadas por algún suceso vital traumático (36,5% de varones), con edades comprendidas entre los 18 y los 71 años. RESULTADOS: el análisis factorial confirmatorio apoyaría la estructura interna propuesta teóricamente para el instrumento. Además, los coeficientes de fiabilidad tanto de las 6 escalas como de la puntuación total son aceptables. CONCLUSIONES: en conjunto, los hallazgos de este estudio avalan el uso del TRauma para medir factores de fortalezas personales y resiliencia. Sin embargo, estos resultados no agotan el proceso de validación del TRauma; es necesario seguir recabando evidencias empíricas

Development and psychometric properties of the Resistance to Trauma Test (TRauma).

BACKGROUND: The Resistance to trauma Test: TRauma is an instrument designed to assess six dimensions involving personal strengths or resources that promote coping with difficult life situations. In addition, an overall score is obtained that is conceptually equivalent to the concept of resilience. The aim of this study was to analyze the psychometric properties and factorial structure of the TRauma in a sample of subjects affected by a traumatic event. METHOD: Participants were 222 people affected by a traumatic life event (36.5% males), with ages ranging between 18 and 71 years. RESULTS: Confirmatory factor analysis supports the theoretical internal structure proposed for the instrument. Moreover, the reliability coefficients of the six scales and the total score are both acceptable. CONCLUSIONS: Overall, the findings of this study support the use of the TRauma to measure factors of personal strengths and resilience. However, these results do not exhaust the validation process of the TRauma, and it is necessary to continue to seek empirical evidence.

Comparison of running characteristics and heart rate response of international and national female rugby sevens players during competitive matches.

This study compared the activity profile of national and international female rugby sevens players during competitive matches. Twenty rugby sevens female players were recruited, 10 were members of the Spanish National Team (26.27 ± 4.05 years, 65.39 ± 5.01 kg, 166.72 ± 6.70 cm) and 10 were amateur athletes from a Spanish rugby championship (32.12 ± 6.40 years, 66.48 ± 5.38 kg of body mass, 167.37 ± 3.02 cm). Data collection was conducted over 4 matches in each of the 2 tournaments, national and international. Distance, velocity, and heart rate (HR) were recorded using global positioning system devices for all participants throughout each match. There were significant differences (p < 0.01) in total distance (1642 ± 171 vs. 1363 ± 222 m), average speed (6.0 ± 0.3 vs. 5.2 ± 0.6 km·h-1), number of sprints (6.1 ± 3.1 vs. 1.9 ± 1.4 sprints), and distance covered in sprinting (118.8 ± 61.4 vs. 47.0 ± 38.8 m). Significant differences were found at >95% maximum HR (HRmax), both for the first (p < 0.01) and second half (p ≤ 0.05). The work-rest ratio was significantly different (p < 0.01) between international (1:0.3) and national players (1:0.4). Significant differences were found in accelerations above 2 m·s-2 in the first and second half between the 2 groups. These findings suggest that distance covered in a match and speed are considerably different between international and national rugby sevens players, and this is reflected as higher intensity of play with consequently higher HR. Coaches may use this information to design specific running drills for this athlete population to match the requirements of national or international game play.

Match-play activity profile in elite women's rugby union players.

The aim of this study was to provide an objective description of the locomotive activities and exercise intensity undergone during the course of an international-level match of female rugby union. Eight players were analyzed using global positioning system tracking technology. The total distance covered by the players during the whole match was 5,820 ± 512 m. The backs covered significantly more distance than the forwards (6,356 ± 144 vs. 5,498 ± 412 m, respectively). Over this distance, 42.7% (2,487 ± 391 m) was spent standing or walking, 35% jogging (2,037 ± 315 m), 9.7% running at low intensity (566 ± 115 m), 9.5% at medium intensity (553 ± 190 m), 1.8% at high intensity (105 ± 74 m), and 1.2% sprinting (73 ± 107 m). There were significant differences in the distance covered by forwards and backs in certain speed zones. Analysis of the relative distance traveled over successive 10-minute period of match play revealed that the greatest distances were covered during the first (725 ± 53 m) and the last (702 ± 79 m) 10-minute period of the match. The average number of sprints, the average maximum distance of sprinting, the average minimum distance of sprinting, and the average sprint distance during the game were 4.7 ± 3.9 sprints, 20.6 ± 10.5 m, 5.8 ± 0.9 -m, and 12.0 ± 3.8 m, respectively. There were substantial differences between forwards and backs. Backs covered greater total distance, distance in certain speed zones, and sprinting performance. The players spent 46.9 ± 28.9% of match time between 91 and 100% of maximum heart rate and experienced a large number of impacts (accelerometer data and expressed as g forces) during the game. These findings offer important information to design better training strategies and physical fitness testing adapted to the specific demands of female rugby union.

Clustering strategies for optimal trial selection in multisensor environments. An eigenvector based approach.

BACKGROUND: Quite often, magnetoencephalography (MEG) measurements are contaminated by a series of artifacts that degrade the quality of the various source localization methods applied to them. In particular, eye blinking, minor head movement and related activities are a constant source of measurement contamination. In order to solve this problem, trial selection and rejection is applied, a task that is usually performed manually. NEW METHOD: The present work shows an automatic trial selection and rejection algorithm based on clustering techniques. These techniques employ a measurement of the dissimilarity of the items belonging to a set. This measure, based on the projection of the eigenvector corresponding to the largest eigenvalue of the covariance matrix, is provided and its rationale is explained. Subsequently, covariance matrices belonging to the selected cluster are averaged and used in the well-known Linearly Constrained Minimum Variance (LCMV) Beamformer. RESULTS: The results show a marked improvement of the specificity of the localization algorithm compared to the application of the LCMV without clustering. COMPARISON WITH EXISTING METHOD(S): The method shows a marked reduction in computational cost compared with other data cleaning procedure widely used: Independent Component Analysis (ICA). CONCLUSIONS: Thus, we propose clustering techniques to be used in brain localization activity algorithms.

Caffeine-containing energy drink improves physical performance of elite rugby players during a simulated match.

The purpose of this study was to investigate the effectiveness of a caffeine-containing energy drink in enhancing rugby players' physical performance during a simulated match. A second purpose was to determine the urinary caffeine excretion derived from the energy drink intake. In a randomized and counterbalanced order, 26 elite rugby players (mean ± SD for age and body mass, 25 ± 2 y and 93 ± 15 kg) played 2 simulated rugby games (2 × 30 min) 60 min after ingesting (i) 3 mg of caffeine per kilogram of body mass in the form of an energy drink (Fure, ProEnergetics) or (ii) the same drink without caffeine (placebo). During the matches, the individual running distance and the instantaneous speed were measured, and the number of running actions above 20 km·h(-1) (i.e., sprints) were determined, using global positioning system devices. The number of impacts above 5 g during the matches was determined by accelerometry. The ingestion of the energy drink, compared with the placebo, increased the total distance covered during the match (4749 ± 589 vs 5139 ± 475 m, p < 0.05), the running distance covered at more than 20 km·h(-1) (184 ± 38 vs 208 ± 38 m, p < 0.05), and the number of sprints (10 ± 7 vs 12 ± 7, p < 0.05). The ingestion of the energy drink also resulted in a greater overall number of impacts (481 ± 352 vs 641 ± 366, p < 0.05) and a higher postexercise urine caffeine concentration (0.1 ± 0.1 vs 2.4 ± 0.9 µg·mL(-1), p < 0.05). The use of an energy drink with a caffeine dose equivalent to 3 mg·kg(-1) considerably enhanced the movement patterns of rugby players during a simulated match.

Caffeine-containing energy drink improves sprint performance during an international rugby sevens competition.

The aim of this study was to determine the effects of a caffeine-containing energy drink on physical performance during a rugby sevens competition. A second purpose was to investigate the post-competition urinary caffeine concentration derived from the energy drink intake. On two non-consecutive days of a friendly tournament, 16 women from the Spanish National rugby sevens Team (mean age and body mass = 23 ± 2 years and 66 ± 7 kg) ingested 3 mg of caffeine per kg of body mass in the form of an energy drink (Fure(®), ProEnergetics) or the same drink without caffeine (placebo). After 60 min for caffeine absorption, participants performed a 15-s maximal jump test, a 6 × 30 m sprint test, and then played three rugby sevens games against another national team. Individual running pace and instantaneous speed during the games were assessed using global positioning satellite (GPS) devices. Urine samples were obtained pre and post-competition. In comparison to the placebo, the ingestion of the energy drink increased muscle power output during the jump series (23.5 ± 10.1 vs. 25.6 ± 11.8 kW, P = 0.05), running pace during the games (87.5 ± 8.3 vs. 95.4 ± 12.7 m/min, P < 0.05), and pace at sprint velocity (4.6 ± 3.3 vs. 6.1 ± 3.4 m/min, P < 0.05). However, the energy drink did not affect maximal running speed during the repeated sprint test (25.0 ± 1.5 vs. 25.0 ± 1.7 km/h). The ingestion of the energy drink resulted in a higher post-competition urine caffeine concentration than the placebo (3.3 ± 0.7 vs. 0.2 ± 0.1 µg/mL; P < 0.05). In summary, 3 mg/kg of caffeine in the form of a commercially available energy drink considerably enhanced physical performance during a women's rugby sevens competition.

Impact of several matches in a day on physical performance in Rugby Sevens referees.

PURPOSE: To examine the effects of several matches per day on running performance and cardiovascular stress in referees during a national Rugby Sevens championship. METHODS: Seven referees, who refereed 3 matches/ day, were monitored by GPS during 21 matches. RESULTS: Referees' movement patterns were relatively stable from the 1st to the 2nd match, although a substantial decrease was observed in the 2nd match for maximal and average sprint distance. A substantial decrease in the number of sprints, maximal speed, walking, distance covered at medium intensity, total and >14 km/h distance covered per minute was observed in the 3rd match in comparison with the 2nd. Compared with the 1st match, in the 3rd game referees showed a substantial decrease in maximal and average sprint distance, total walking at medium intensity, distance covered >14 km/h, and high-intensity running distance. Referees exhibited a substantial decrease in average heart rate (HR), percentage of time at >70%HRmax, and percentage of time at >90%HRmax in the 2nd match compared with the 1st. Referees' HR responses were relatively stable from the 2nd to the 3rd match except for the HR zones of 71-80%HRmax and 81-90%HRmax and performance-efficiency index (Effindex). Substantial differences were observed in the 3rd match compared with the 1st in average HR, 81-90%HRmax, >90%HRmax, and Effindex. CONCLUSION: This study provides evidence of reduced overall running performance and pronounced reduction in high-intensity running performance during the last match in Rugby Sevens referees refereeing 3 matches in the same day.