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Empirical observations support that the addition of a plastic strip - also known as Randall foils - on the top edge of a rowing blade improves rowing efficiency during the cycle propulsive phase. The aim of the current study was to analyze the effect of using big blades with and without Randall foils on rowing performance. Twenty experienced rowers performed two 90 s tethered rowing bouts (with and without Randall foils) to assess their impact on force production and physiologic variables. All tests were randomized and a repeated measure design was used to compare experimental conditions. Higher values of peak and mean peak forces (479.4±134.7 vs. 423.2±153.0, d=0.83 and 376.5±101.4 vs. 337.1±113.3 N, d=0.68), peak oxygen uptake (47.9±7.5 vs. 45.3±7.3 mLâkg-1âmin-1, d=0.19), peak blood lactate concentration (7.9±1.6 vs. 6.9±1.7 mmolâL-1, d=0.16), blood lactate increasing speed (0.08±0.01 vs. 0.07±0.06 [(mmol·L-1)·s-1], d=0.27) and lactic anaerobic energy (27.4±7.9 vs. 23.4±8.1 kJ, d=0.23) were found for big blades with vs. without Randall foils, p<0.05. The current data suggest that the Randall foils can positively affect rowing performance.
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Esportes Aquáticos , Humanos , Lactatos , Consumo de OxigênioRESUMO
This study aimed to compare three swimming conditions in a swimming flume with water at 26 â (using swimsuit) and 18 â (randomly with swimsuit and wetsuit). Seventeen swimmers (32.4±14.7 years old, 175.6±0.06 cm height, and 70.4±9.8 kg body mass) performed three bouts until exhaustion at a 400-m front crawl pace (24 h intervals). ANOVA repeated measures compared the experimental conditions. Swimming at 26 â with swimsuit evidenced a higher metabolic demand (total energy expenditure; (E)), comparing to 18 â swimsuit (p=0.05) and with 18 â wetsuit (p=0.04). The 26 â swimsuit condition presented higher peak oxygen uptake (VO2peak), blood lactate concentrations ([La-]peak), rate of perceived exertion (RPE), maximal heart rate (HRmax), anaerobic lactic energy (AnL), E, energy cost (C), VÌO2 amplitude (Ap), and stroke rate (SR), but lower stroke length (SL) and stroke index (SI) than 18 â wetsuit. The 18 â swimsuit condition (comparing to wetsuit) lead to higher VÌO2peak, [La-]peak, HRmax, E, C, Ap, and SR but lower SL and SI. Swimming at aerobic power intensity with swim and wetsuit at 18 â does not induce physiologic and biomechanical disadvantages compared to 26 â. The results suggested that the use of wetsuit might increase performance at 18 â water temperature for competitive master swimmers. Its use is thus recommended in open water swimming competitions when the water temperature is 18-20 â.
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Vestuário , Natação , Temperatura , Adolescente , Adulto , Desempenho Atlético , Temperatura Baixa , Metabolismo Energético , Frequência Cardíaca , Humanos , Ácido Láctico/sangue , Pessoa de Meia-Idade , Consumo de Oxigênio , Equipamentos Esportivos , Natação/fisiologia , Água , Adulto JovemRESUMO
OBJECTIVE: Cardiopulmonary resuscitation (CPR) after a drowning episode is performed under fatigue conditions. However, the characterization of CPR in this context is still unknown. Our purpose was to investigate the effect of a 100-m simulated in-water rescue on CPR and physiological parameters in trained certified lifeguards. METHODS: Thirty trained certified lifeguards (age 24.6 ± 3.8 yrs; height 178.2 ± 7.4 cm and weight 76.9 ± 10.6 kg) completed two protocols using an adult manikin: (i) 4-min CPR after 4-min baseline conditions (CPR), and (ii) 4-min CPR after a 100-m simulated in-water rescue in the sea (CPR Rescue), both with a compression-ventilation ratio of 30:2. Physiological parameters of the subjects were continuously measured (breath-by-breath) during baseline and CPR conditions, using a telemetric portable gas analyzer (K4b 2 , Cosmed, Rome, Italy) and CPR techniques analyzed using two HD video cameras (Sony, HDR PJ30VE, Japan). RESULTS: The 100-m simulated in-water rescue induced higher values of physiological related parameters all over the 4-min CPR exercise (e.g. Tidal Volume: 1.5 ± 0.4 and 2.4 ± 0.5 L; VO2: 15.9 ± 3.9 and 22.8 ± 3.2 ml.kg-1.min-1; R: 0.9 ± 0.1 and 1.2 ± 0.1, for CPR and CPR Rescue, respectively). However, the compression rate was higher in CPR Rescue compared to the CPR in the first (cycle 3: 85 ± 12 vs. 78 ± 9 s) and last three complete cycles (cycle 12: 100 ± 12 and 85 ± 12 s), and, in both conditions, it increased from the first to the last CPR complete cycle. CONCLUSIONS: Fatigue induced by the 100-m simulated in-water rescue had a strong physiological expression but a minimal impact on CPR performance. Key words: CPR; fatigue; lifeguards; VO2.
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Reanimação Cardiopulmonar/métodos , Afogamento , Fadiga , Treinamento por Simulação , Adulto , Protocolos Clínicos , Humanos , Masculino , Manequins , Natação , Adulto JovemRESUMO
We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = -0.82; 95% CI: -1.56, -0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = -0.81; 95% CI: -1.55, -0.07), centre of mass (CM) vertical positioning at first water contact (SMD = -0.97; 95% CI: -1.87, -0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: -0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.
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Desempenho Atlético , Pé , Mãos , Postura , Natação , Adolescente , Adulto , Tornozelo , Articulação do Tornozelo , Fenômenos Biomecânicos , Força da Mão , Humanos , Joelho , Articulação do Joelho , Masculino , Água , Adulto JovemRESUMO
This study was conducted with the following aims: (a) to describe the effect of playing position on anthropometrics and throwing velocity in elite female water polo players and (b) to observe any relationships between anthropometric parameters and throwing velocity. To achieve these aims, we analyzed a total of 46 female elite players (age: 22.5 ± 5.1 years; height: 172.0 ± 6.9 cm, body mass: 67.4 ± 7.5 kg) members of the top 4 teams of the Spanish Honour Division women league (21 offensive wings players, 17 center, and 8 goalkeepers). Wings were significantly shorter and had smaller arm spans than goalkeepers and center players. Goalkeepers demonstrated longer forearm lengths than wing and center players. No other significant differences were evident between positions in terms of anthropometric, strength, or throwing velocity variables The somatotype of the offensive wing players was mesomorphic, whereas centers were endomorph (classified as endomesomorphic). Height, arm span, muscular mass, biepicondylar breadth of the humerus, arm girth (relaxed and tensed), and forearm girth were related to throwing velocity. In conclusion, only a small number of anthropometric differences exist between players of different positions in elite female water polo. Shorter players with smaller arm spans may be better suited to the wings, whereas athletes with longer forearms may be better suited to the goalkeeper position. Taller, more muscular athletes with wider arm spans, broader humeri, and wider arms (relaxed and flexed) tended to throw with increased velocity. Trainers should focus on increasing the modifiable characteristics (muscle mass and arm girths) that contribute to throwing velocity in this population.
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Desempenho Atlético/fisiologia , Somatotipos/fisiologia , Esportes/fisiologia , Extremidade Superior/anatomia & histologia , Extremidade Superior/fisiologia , Adulto , Estatura/fisiologia , Estudos Transversais , Feminino , Humanos , Movimento/fisiologia , Músculo Esquelético/fisiologia , Adulto JovemRESUMO
The aim of this study was to analyze the degree of prediction to which the goal orientation adopted by the student and the motivational climate created by the teacher as perceived by students in physical education classes, have on the students' self-determined behaviors. The sample included 846 high school students from the Murcia region (Spain) aged 12-19 years old. The Spanish versions of the Perception of Success Questionnaire, the Perceived Motivational Climate in Sport Questionnaire-2 and the Motivational Climate Scale were the instruments used to collect data. A descriptive, correlated and stepwise multiple regression analysis was carried out following the Self Determination Index. Results show that the majority of students were task oriented, they perceive a task climate and were intrinsically motivated. Moreover, the relevance of the role of the teacher in physical education classes was demonstrated, as the main predictor variable of self-determined behavior in students was the motivational climate.
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Objetivos , Motivação , Educação Física e Treinamento/métodos , Logro , Adolescente , Criança , Feminino , Promoção da Saúde/métodos , Humanos , Masculino , Análise Multivariada , Autonomia Pessoal , Análise de Regressão , Espanha , Esportes , Estudantes , Inquéritos e Questionários , Adulto JovemRESUMO
The aim of this study was to investigate the factor structure of a Spanish version of the Sport Motivation Scale adapted to physical education. A second aim was to test which one of three hypothesized models (three, five and seven-factor) provided best model fit. 758 Spanish high school students completed the Sport Motivation Scale adapted for Physical Education and also completed the Learning and Performance Orientation in Physical Education Classes Questionnaire. We examined the factor structure of each model using confirmatory factor analysis and also assessed internal consistency and convergent validity. The results showed that all three models in Spanish produce good indicators of fitness, but we suggest using the seven-factor model (χ(2)/gl = 2.73; ECVI = 1.38) as it produces better values when adapted to physical education, that five-factor model (χ(2)/gl = 2.82; ECVI = 1.44) and three-factor model (χ(2)/gl = 3.02; ECVI = 1.53). Key PointsPhysical education research conducted in Spain has used the version of SMS designed to assess motivation in sport, but validity reliability and validity results in physical education have not been reported.Results of the present study lend support to the factorial validity and internal reliability of three alternative factor structures (3, 5, and 7 factors) of SMS adapted to Physical Education in Spanish.Although all three models in Spanish produce good indicators of fitness, but we suggest using the seven-factor model.
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The purpose of this study was twofold. Firstly to examine the relations between the different constructs that defines Nicholls' Achievement Goal Theory and Deci and Ryan's self-determination theory. Secondly to analyse the differences that exist between them with respect to the socio-demographic variables gender and age. A sample of 292 federated basketball players from the Region of Murcia (Spain) with ages between 14 and 18 years old was used. In addition, Castilian versions of The Perception of Success Questionnaire (POSQ) and the Sports Motivational Scale (SMS) were administered. Three statistical analyses were employed, a descriptive analysis, a correlation analysis and a regression analysis. The results showed a positive relation between ego orientation, extrinsic motivation and amotivation. The motivational relations between both theories and the differences with respect to gender and age are discussed. We have found out that mainly gender and also age differences are strong predictors of ego orientation, extrinsic motivation of external regulation and amotivation. We can also confirm that extrinsic motivation of external regulation positively predicts ego orientation and a decrease of task orientation. The results ratify the use of the Spanish version of the SMS to measure different types of motivation within the sports context.
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Basquetebol/psicologia , Objetivos , Motivação , Autonomia Pessoal , Psicologia do Adolescente , Adolescente , Feminino , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
The aim of this study was to define and examine the relationships between the anthropometrical characteristics, maximum isometric grip strength, and competition throwing velocities and efficacy indices in high-level water polo player. Eleven elite trained male water polo players participated in this study. During preseason training, the following measures were taken: standard anthropometry (height, body mass, arm spam, skinfolds, body girths, and skeletal breadths) and grip strength. During official European Competitions (n = 7), efficacy indices (offensives: shot definition, resolution, precision, blocked and defensives: shot resolution when defending and shots stopped when defending), average and maximum throwing velocities from all the participants by zones and in some offensive tactical phases (even, counterattacks and power play) were also determined. Throwing velocities were different (p ≤ 0.05) between some of the offensive tactical phases (even = 17.9 ± 2.4 vs. power play = 16.7 ± 2.6 m·s(-1)). In addition, significant correlations were found between competitive throwing velocities and different offensive efficacy indices. We concluded that there were significant correlations between conditioning and performance variables with anthropometrical characteristics and offensive tactical indices (blocked shots received and shot precision). Coaches should pay attention to these indices for the development of performance throughout the season.
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Desempenho Atlético/fisiologia , Tamanho Corporal , Força da Mão/fisiologia , Esportes/fisiologia , Adulto , Humanos , Masculino , Aptidão Física/fisiologia , Dobras Cutâneas , Adulto JovemRESUMO
The aim of this study was an analysis of the time required to swim to a victim and tow them back to shore, while perfoming the flutter-kick and the dolphin-kick using fins. It has been hypothesized that using fins while using the dolphin-kick when swimming leads to reduced rescue time. Sixteen lifeguards took part in the study. The main tasks performed by them, were to approach and tow (double armpit) a dummy a distance of 50m while applying either the flutter-kick, or the dolphin-kick with fins. The analysis of the temporal parameters of both techniques of kicking demonstrates that, during the approach to the victim, neither the dolphin (tmean = 32.9s) or the flutter kick (tmean = 33.0s) were significantly faster than the other. However, when used for towing a victim the flutter kick (tmean = 47.1s) was significantly faster when compared to the dolphin-kick (tmean = 52.8s). An assessment of the level of technical skills in competitive swimming, and in approaching and towing the victim, were also conducted. Towing time was significantly correlated with the parameter that linked the temporal and technical dimensions of towing and swimming (difference between flutter kick towing time and dolphin-kick towing time, 100m medley time and the four swimming strokes evaluation). No similar interdependency has been discovered in flutter kick towing time. These findings suggest that the dolphin-kick is a more difficult skill to perform when towing the victim than the flutter-kick. Since the hypothesis stated was not confirmed, postulates were formulated on how to improve dolphin-kick technique with fins, in order to reduce swimming rescue time.
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High performance sport for females is an area which is gaining more and more relevance today, but which hasn't received the same research interest as sport for males. The aim of the present study was to analyse the motivational climate perceived by high performance female athletes and the implications on perceived motor competence and autonomous behaviour and check the differences according category, sport experience and training hours in performance and master climate. The participants were 615 female athletes who practice top level team sports, with ages comprised of 16 to 38 (M = 22,10; SD = 4,91). The sample consisted of two different categories: junior (n = 242) and senior (n = 373). These players participated in different team sports, specifically football, handball, basketball and volleyball, training between 6 and 24 hours a week (M = 8,34; DT = 4,33). The variables measured were: perceived motivational climate in sport, autonomous behaviour and perceived motor competence. A cluster analysis was carried out using, as a variable, the perceived motivational climate, and showing the existence of two profiles, one related to ego and the other to task. The multivariate analysis showed that the profile orientated towards the task had significant differences compared to the autonomous behaviour (M = 4.66 vs M = 3.41). At the same time an analysis was carried out looking at different social demographic variables, revealing how there were differences in the sports experience (those participants with more than ten years' experience were more orientated towards ego, compared to those with less than ten years' experience) and the category (junior athletes were more orientated towards the task, compared to senior athletes). It was concluded that a greater orientation towards the task can lead to an improvement in the perception of motor competence, with the youngest and least experienced athletes being the most prominent in this category.
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Basquetebol , Futebol Americano , Voleibol , Humanos , Feminino , Esportes de Equipe , Análise por ConglomeradosRESUMO
Water polo is a team sport that has been suffering rule changes aiming for a more attractive game. Our goal was to unveil whether different offensive playing styles or methods were adopted by elite national teams from Eastern Europe and from other world countries after the new rules framework was applied at the 2019 FINA World Championship. Additionally, we questioned whether those rules induced a more dynamic game. A total of 648 offensive sequences from games contested by the top-six ranked national squads were analysed. Descriptive statistics, parametric and nonparametric tests were computed, and the effect size was used. The eastern Europeans were the tallest (t (76) = −4.081; p < 0.001, d = 0.42) and the Hungarians were higher than Italians (p = 0.005, dz = −0.41). Offensive time length differed between teams (H (5) = 30.50, p < 0.001) with Serbia being the fastest (Mdn = 22 s). In successful attacks without extra time, Italy was quicker than Spain (17.5 vs. 25.0 s; p = 0.031, dz = −0.36) scoring 30% of their total goals under 20 s, while Australia up to 24% and Croatia, Hungary and Spain ≤ 16.0%. When power-play occurred, the teams' pass action was different (H (5) = 15.99, p < 0.007), with Italy performing more passes than counterparts, especially Serbia (Mdn = 13 vs. 9, respectively; p= 0.003, dz = 0.20) and with the exception of Hungary. Through fast play sequences, Italy, Serbia and Australia scored up to 33% of their goals, while Spain, Croatia, and Hungary scored ≤ 15%. The power-play contributed to ≥50% of teams' goals, except for Spain and Australia (48 and 45%, respectively). Playing styles commonly attributed to Eastern vs. non-Eastern Europeans and other worldwide national teams such as Australia were not confirmed. However, offensive trends were perceived and described for the first time, and some base guidelines were suggested to distinguish the static or positional vs. a more dynamic playing model. Rule changes did not seem to induce the expected effects on game dynamics.
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Desempenho Atlético , Esportes Aquáticos , Logro , Humanos , Espanha , Esportes de EquipeRESUMO
Water polo is a team sport characterized by a high-intensity, intermittent activity, where technical and tactical aspect are of a great importance. For that reason, the main aim of this study was to define the anthropometrical characteristics, maximum isometric grip strength, training and competition throwing velocities, and the efficacy indices in female high-level water polo players. A second purpose was to examine the differences between the throwing velocities in training vs. European championships in the water polo female national team. Ten elite trained female water polo players participated in this study. Before the competitive phase of their season, the following measures were taken: standard anthropometry, static and dynamic training throwing velocities, and hand-grip dynamometry. In the competitive phase, efficacy indices, average and maximum throwing velocities from all the participants were also determined. Significant differences (p ≤ 0.05) were found between different training situations and different competitive throwing velocities. We concluded that elite female water polo players modify their throwing velocity depending if the throw is performed during training or competitive situation.
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Desempenho Atlético/fisiologia , Pesos e Medidas Corporais , Esportes/fisiologia , Adulto , Atletas , Feminino , Força da Mão/fisiologia , Humanos , Adulto JovemRESUMO
Survival outcomes increase significantly when cardiopulmonary resuscitation (CPR) is provided correctly, but rescuers' fatigue can compromise its delivery. We investigated the effect of two exercise modes on CPR effectiveness and physiological outputs. After 4 min baseline conditions, 30 lifeguards randomly performed a 100 m run and a combined water rescue before 4 min CPR (using an adult manikin and a 30:2 compression-ventilation ratio). Physiological variables were continuously measured during baseline and CPR using a portable gas analyzer (K4b2, Cosmed, Rome, Italy) and CPR effectiveness was analyzed using two HD video cameras. Higher oxygen uptake (23.0 ± 9.9 and 20.6 ± 9.1 vs. 13.5 ± 6.2 mL·kg·min-1) and heart rate (137 ± 19 and 133 ± 15 vs. 114 ± 15 bpm), and lower compression efficacy (63.3 ± 29.5 and 62.2 ± 28.3 vs. 69.2 ± 28.0%), were found for CPRrun and CPRswim compared to CPRbase. In addition, ventilation efficacy was higher in the rescues preceded by intense exercise than in CPRbase (49.5 ± 42.3 and 51.9 ± 41.0 vs. 33.5 ± 38.3%), but no differences were detected between CPRrun and CPRswim. In conclusion, CPRrun and CPRswim protocols induced a relevant physiological stress over each min and in the overall CPR compared with CPRbase. The CPRun protocol reduces the compression rate but has a higher effectiveness percentage than the CPRswim protocol, in which there is a considerably higher compression rate but with less efficacy.
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Reanimação Cardiopulmonar , Corrida , Adulto , Fadiga , Humanos , Manequins , NataçãoRESUMO
This study aimed to analyze the effects of a swimming training mesocycle in master swimmers' performance and active drag. Twenty-two 39.87 ± 6.10 year-old master swimmers performed a 25 m front crawl at maximal intensity before and after a typical four-week training mesocycle. Maximum, mean and minimum speeds, speed decrease and hip horizontal intra-cyclic velocity variation were assessed using an electromechanical speedometer, and the active drag and power to overcome drag were determined using the measuring active drag system. Maximum, mean and minimum front crawl speeds improved from pre- to post-training (mean ± 95% CI: 3.1 ± 2.8%, p = 0.04; 2.9 ± 1.6%, p = 0.01; and 4.6 ± 3.1%, p = 0.01; respectively) and the speed decrease along the 25 m test lowered after the training period (82.5 ± 76.3%, p = 0.01). The training mesocycle caused a reduction in the active drag at speeds corresponding to 70% (5.0 ± 3.9%), 80% (5.6 ± 4.0%), and 90% (5.9 ± 4.0%), but not at 100% (5.9 ± 6.7%), of the swimmers' maximal exertions in the 25 m test. These results showed that four weeks of predominantly aerobic training could improve master swimmers' performance and reduce their hydrodynamic drag while swimming mainly at submaximal speeds.
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Hidrodinâmica , Natação , Fenômenos Biomecânicos , HumanosRESUMO
We compared the hydrodynamic characteristics and pull-out strategies of four backstroke-to-breaststroke turning techniques in young swimmers. Eighteen 11 and 12-year-old swimmers participated in a 4 week intervention program including 16 contextual interference sessions. The hydrodynamic variables were assessed through inverse dynamics, and the pull-out strategy kinematics were assessed with tracking markers followed by 12 land cameras and 11 underwater cameras. Swimmers randomly completed sixteen 30 m maximal backstroke-to breaststroke-open, somersault, bucket and crossover turns (four in each technique) with a 3 min rest. The data showed higher drag force, cross-sectional area and drag coefficient values for the first (compared with the second) gliding position. The crossover turn revealed the highest push-off velocity (2.17 ± 0.05 m·s-1), and the somersault turn demonstrated the lowest foot plant index (0.68 ± 0.03; 68%), which could have affected the first gliding, transition and second gliding depths (0.73 ± 0.13, 0.86 ± 0.17 and 0.76 ± 0.17 m). The data revealed the consistency of the time spent (4.86 ± 0.98 s) and breakout distance (6.04 ± 0.94 m) among the four turning techniques, and no differences were observed between them regarding time and average velocity up to 7.5 m. The hydrodynamic characteristics and pull-out strategy of the backstroke-to-breaststroke turns performed by the age group swimmers were independent of the selected technique.
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Desempenho Atlético , Hidrodinâmica , Fenômenos Biomecânicos , Pé , NataçãoRESUMO
Survival outcomes increase significantly when cardiopulmonary resuscitation (CPR) is provided correctly, but rescuer's fatigue can compromise CPR delivery. We investigated the effect of a 100-m maximal run on CPR and physiological variables in 14 emergency medical technicians (age 29.2 ± 5.8 years, height 171.2 ± 1.1 cm and weight 73.4 ± 13.1 kg). Using an adult manikin and a compression-ventilation ratio of 30:2, participants performed 4-min CPR after 4-min baseline conditions (CPR) and 4-min CPR after a 100-m maximal run carrying emergency material (CPR-run). Physiological variables were continuously measured during baseline and CPR conditions using a portable gas analyzer (K4b2, Cosmed, Rome, Italy) and analyzed using two HD video cameras (Sony, HDR PJ30VE, Japan). Higher VO2 (14.4 ± 2.1 and 22.0 ± 2.5 mL·kg-1·min-1) and heart rate (123 ± 17 and 148 ± 17 bpm) were found for CPR-run. However, the compression rate was also higher during the CPR-run (373 ± 51 vs. 340 ± 49) and between every three complete cycles (81 ± 9 vs. 74 ± 14, 99 ± 14 vs. 90 ± 10, 99 ± 10 vs. 90 ± 10, and, 101 ± 15 vs. 94 ± 11, for cycle 3, 6, 9 and 12, respectively). Fatigue induced by the 100-m maximal run had a strong impact on physiological variables, but a mild impact on CPR emergency medical technicians' performance.
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Reanimação Cardiopulmonar/normas , Fadiga/etiologia , Parada Cardíaca/terapia , Esforço Físico , Adulto , Reanimação Cardiopulmonar/métodos , Feminino , Humanos , Itália , Japão , Masculino , Manequins , Cidade de Roma , Fatores de TempoRESUMO
Physiological responses related to 400-m front crawl performance were examined in a 11-week training macrocycle in children 11.6 ± 1.2 years old. Fourteen girls and twenty-nine boys completed a maximum intensity 400-m test, at the beginning (Τ1) and at the end of four weeks of general preparation (Τ2), four weeks of specific preparation (Τ3), and three weeks of the competitive period (Τ4). Blood lactate (La), blood glucose (Glu) and heart rate were measured post effort. Stroke rate (SR), stroke length (SL) and stroke index (SI) were measured during the test. The 400-m time was decreased at T2, T3, and T4 compared to T1 by 4.2 ± 4.9, 7.5 ± 7.0, and 8.6 ± 7.3% (p < 0.05) and at T3 and T4 compared to T2 by 3.1 ± 4.3 and 4.2 ± 4.6%, respectively (p < 0.05). La was not different between tests (p > 0.05) and Glu was decreased at T3 compared to other testing moments (p < 0.05). SR, SL, and SI were higher at T3 and T4 compared to T1 (p < 0.05). SL and SI were also increased at T4 compared to T2 (p < 0.05). Performance changes from T1 to T2 were related to SL and SI changes (r = 0.45 and 0.83, p < 0.05), and subsequent changes between T2 to T3 were related to SR, SI, La, and Glu changes (r = 0.48, 0.68, 0.34, and 0.42, p < 0.05). Performance change from T3 to T4 was related to SL, SI, and La modifications (r = 0.34, 0.70, and 0.53, p < 0.05). Performance gains may be related to various biomechanical or physiological changes according to training macrocycle structure.
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The purpose of the study is to examine the effects of the motivational climate created by the coach and perceived by a group of young handball players on their goal orientations, their beliefs regarding reasons for success and their self-satisfaction. The study participants were 159 young handball players. Players were administered a battery composed of tests to measure the above-mentioned motivational constructs. Results showed that a perceived mastery-oriented motivational climate was positively related to a task-centered goal orientation, enjoyment, and a belief that success may be achieved through effort. In contrast, a perceived performance-orientated training climate was linked to an ego-centered goal orientation, boredom, or lack of enthusiasm, and a belief that the routes of success in this sport are the abilities and the use of deception techniques. On the whole, this study underlines the educational role of the coach in young handball players. Specifically, the coach's socializing role influences both handball player's commitment and positive motivational profile as well as sport performance.
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Foot and hand set-up position effects were analysed on backstroke start performance. Ten swimmers randomly completed 27 starts grouped in trials (n = 3) of each variation, changing foot (totally immersed, partially and totally emerged) and hand (lowest, highest horizontal and vertical) positioning. Fifteen cameras recorded kinematics, and four force plates collected hands and feet kinetics. Standardised mean difference and 95% confidence intervals were used. Variations with feet immersed have shown lower vertical centre of mass (CM) set-up position (0.16 m), vertical impulse exerted at the hands, horizontal and vertical impulse exerted at the feet (0.28, 0.41, 0.16 N/BW.s, respectively) than feet emerged with hands horizontal and vertically positioned. Most variations with feet partially emerged exhibited higher and lesser vertical impulse exerted at hands than feet immersed and emerged (e.g. vertical handgrip, 0.13, 0.15 N/BW.s, respectively). Variation with feet emerged and hands on the lowest horizontal handgrip depicted shorter horizontal (0.23, 0.26 m) and vertical CM positioning at flight (0.16, 0.15 m) than the highest horizontal and vertical handgrip, respectively. Start variations have not affected 15-m time. Variations with feet partially or totally emerged depicted advantages, but focusing on the entry and underwater biomechanics is relevant for a shorter start time.