Swimming With the COSMED AquaTrainer and K5 Wearable Metabolic System in Breath-by-Breath Mode: Accuracy, Precision, and Repeatability.

PURPOSE: To compare ventilatory and cardiorespiratory responses between the COSMED AquaTrainer coupled with the K4b2 and K5 wearable metabolic systems in breath-by-breath mode over a wide range of swimming speeds. METHODS: Seventeen well-trained master swimmers performed 2 front-crawl 7 × 200-m incremental intermittent protocols (increments of 0.05 m·s-1 and 30-s rest intervals, with a visual pacer) with AquaTrainer coupled with either K4b2 or K5. RESULTS: Post hoc tests showed that swimming speed was similar (mean diff.: -0.01 to 0.01 m·s-1; P = .73-.97), repeatable (intraclass correlation coefficient: .88-.99; P < .001), highly accurate, and precise (agreement; bias: -0.01 to 0.01 m·s-1; limits: -0.1 to 0.1 m·s-1) between all conditions. Ventilatory and cardiorespiratory responses were highly comparable between all conditions, despite a "small" effect size for fraction of expired carbon dioxide at the sixth 200-m step (0.5%; ηp2=.12; P = .04) and carbon dioxide production at the fifth, sixth, and seventh 200-m steps (0.3-0.5 L·min-1; ηp2=.11-.17; P = .01-.05). We also observed high accuracy, which was greater for tidal volume (0.0-0.1 L), minute ventilation (-3.7 to 5.1 L·min-1), respiratory frequency (bias: -2.1 to 1.9 breaths·min-1), and oxygen uptake (0.0-0.2 L·min-1). Bland-Altman plots showed that the distribution inside the limits of agreement and their respective 95% CIs were consistent for all ventilatory and cardiorespiratory data. The repeatability (intraclass correlation coefficient) of tidal volume (.93-.97), minute ventilation (.82-.97), respiratory frequency (.68-.96), fraction of expired carbon dioxide (.85-.95), carbon dioxide production (.77-.95), fraction of expired oxygen (.78-.92), and oxygen uptake (.94-.98) data ranged from moderate to excellent (P < .001-.05). CONCLUSIONS: Swimming with the AquaTrainer coupled with K5 (breath-by-breath mode) yields accurate, precise, and repeatable ventilatory and cardiorespiratory responses when compared with K4b2 (previous gold standard). Swimming support staff, exercise and health professionals, and researchers can now relate differences between physiological capacities measured with the AquaTrainer while coupled with either of these 2 devices.

Kinematic, arm-stroke efficiency, coordination, and energetic parameters of the 400-m front-crawl test: A meta-analysis.

Several studies have investigated biomechanical and energetic parameters in competitive swimming. Among these studies, it is possible to identify the 400-m front crawl as a useful test to assess these parameters. The present study provided a meta-analysis assessing representative variables for the kinematic, arm-stroke efficiency, coordination, and energetic parameters of the 400-m front crawl test. PubMed, Embase, Web of Science, and SPORTDiscus were the databases used to select the studies published between January 1970 and December 2022. Forty studies (n = 651 swimmers) were selected according to the eligibility and inclusion criteria. The variables chosen to represent each parameter were: clean swim speed (kinematics); index of coordination (coordination); arm-stroke efficiency (efficiency); and oxygen consumption (energetic). Swimming speed was moderate (1.34 m s-1) compared to the world's records performers. Thus, this speed contributed for the swimmers in remaining at high efficiency (35%), imposing a capture coordination model (index of coordination: -11%) with high oxygen consumption (58.8 ml·kg-1 min-1). High heterogeneity (>75%) was found among the outcome parameters in the studies. The different average speeds that represented the kinematic parameters seem to be the most responsible and influential in the arm-stroke efficiency, coordination, and energetic parameters for high 400-m freestyle (front crawl) performance. This meta-analysis can help researchers, coaches, and swimmers improving competitive performance, and developing further research in the sports sciences area, specifically in the swimming.

Kinematics and physiological parameters in maximal swimming tests in age-group swimmers / Cinemática y parámetros fisiológicos en pruebas de natación máxima en nadadores de grupos de edad

Objective: The aim of this study was compared and correlate kinematics and physiological parameters in four maximal swimming tests of two groups of young swimmers.Methods: Twelve swimmers, separated in two groups by age (percentile > 50th (n = 6): 15.4 ± 1.11 years old as group 1, and < 50th (n = 6): 12.1 ± 0.83 as group 2) performed four tests during two different sessions. . They performed front crawl trials at maximum intensity: 50 and 200 meters on first day and 100 and 400 m meters on second day. Anthropometric characteristics were measured. Stroke rate, stroke length, stroke index, swimming speed and critical speed were obtained by video analysis. Moreover, were measured the blood lactate concentration, heart rate and rate of perceived exertion.Results: There are no differences at anthropometric characteristics. We found difference between group 1 and group 2. Better results for performance, swimming speed, stroke length and stroke index in group 1. Swimming speed and stroke index show strong correlation in all tests for group 1 and in 50 and 100 meters for group 2. To measure the swimmer profile is essential to verify the benefits that the training program is or is not providing.Conclusion: The parameters evaluated seem related to age and capacities of the swimmers.(AU)

Three-dimensional front crawl arm-stroke efficiency and hand displacement in male and female swimmers.

This study aimed (i) to verify if underwater horizontal, vertical and medio-lateral hand displacements (HD), in pull and push phases of the front crawl stroke, can be associated with arm-stroke efficiency (ƞp) and (ii) to compare np and selected kinematic variables between male and female swimmers. Ten male and 10 female swimmers performed an all-out front crawl 25-m test. Data were obtained with six synchronised video cameras (60 Hz) and analysed with a three-dimensional method. Results for males and females were respectively, as follows: (i) horizontal HD: 0.55 ± 0.06 m and 0.61 ± 0.09 m (p = 0.062; d = 0.78); vertical HD: 0.68 ± 0.06 m and 0.58 ± 0.07 m (p < 0.001; d = 1.53); and medio-lateral HD: 0.22 ± 0.07 m and 0.16 ± 0.03 m (p = 0.012; d = 1.11); (ii) ƞp: 0.33 ± 0.02 and 0.32 ± 0.03 (p = 0.48; d = 0.39); (iii) vCOM: 1.77 ± 0.06 m∙s-1 and 1.55 ± 0.10 m∙s-1 (p < 0.001; d = 2.42). Multiple linear regression (p = 0.019) indicated that horizontal and medio-lateral HD were able to predict np. The lower the horizontal hand displacement, the higher the ƞp.

Burpee Interval Training Is Associated With a More Favorable Affective Valence and Psychological Response Than Traditional High Intensity Exercise.

Acute psychological responses to physical activity may help explain long-term adherence to it. Thus, we compared acute psychological responses to different exercise protocols with identical durations. Eighteen moderately active young adults [Mage = 23, SD = 3 years; MVO2max (maximum oxygen consumption) = 42.8, SD = 4.3 mL·kg-1·min-1; MBMI (body mass index) = 24, SD = 2 kg·m-2] completed three low-volume exercise sessions in a crossover research design: (a) sprint interval training (SIT), (b) burpee interval training (BIT) requiring 10 × 5 second efforts with 35 seconds of passive recovery, and (c) a single bout of vigorous intensity continuous training (VICT) requiring 6 minutes and 5 seconds of running at ∼85% of peak heart rate (HRpeak). We assessed participants' ratings of perceived exertion (RPE), affective valence, enjoyment, intention, preference, and self-reported recovery and wellness before, during, and after each session. BIT was associated with significantly greater enjoyment, preference, and exercise intention (at 5 × week) than VICT (p ≤ .05). SIT elicited greater RPE (M = 5.38, SD = 2.00) than both BIT (M = 2.88, SD = 1.23) and VICT (M = 3.55, SD = 1.38) (p ≤ .05), and we observed a higher increase in RPE over time with SIT versus BIT (p = .019). For affective valence, SIT (M = 0.55, SD = 2.12) elicited a more aversive response than both BIT (M = 2.55, SD = 1.09) and VICT (M = 1.94, SD = 1.51) (p ≤ .05), and there was a higher increase in this aversive response to SIT over time (p < .05). Forty-eight-hour postexercise session muscle soreness was significantly lower with VICT than with BIT (p = .03). Overall, BIT was associated with more positive psychological responses than SIT and VICT.

The Impact of a Swimming Training Season on Anthropometrics, Maturation, and Kinematics in 12-Year-Old and Under Age-Group Swimmers: A Network Analysis.

Understanding fluctuations and associations between swimming performance-related variables provide strategic insights into a swimmer's preparation program. Through network analysis, we verified the relationships between anthropometrics, maturation, and kinematics changes (Δ) in 25-m breaststroke (BREAST) and butterfly (FLY) swimming performance, before and after a 47-week swimming training season. Twenty age-group swimmers (n =11 girls: 10.0 ± 1.3 years and n = 9 boys: 10.5 ± 0.9 years) performed a 25-m all-out swim test (T25) in BREAST and FLY techniques, before and after 47 weeks. Three measures of centrality, transformed into a z-score, were generated: betweenness, closeness, and strength. Data were compared (t-test) and effect sizes were identified with Hedges' g. Large effect sizes were observed for swimming performance improvements in BREAST (32.0 ± 7.5 to 24.5 ± 3.8 s; g = 1.26; Δ = -21.9 %) and FLY (30.3 ± 7.0 to 21.8 ± 3.6 s; g = 1.52; Δ = -26.5 %). Small to moderate effect sizes were observed for anthropometric changes. Moderate effect size was observed for maturity offset changes (-2.0 ± 0.9 to -1.3 ± 1.0; g = 0.73; Δ = 50.9 ± 281 %). Changes in maturity offset, stroke rate (SR), and stroke length for both BREAST and FLY swimming speeds were highlighted by the weight matrix. For betweenness, closeness, and strength, changes in arm span (AS) (BREAST) and stroke length (FLY) were remarkable. The dynamic process of athletic development and the perception of complexity of fluctuations and associations between performance-related variables were underpinned, particularly for simultaneous swimming techniques in age-group swimmers.

200-m front crawl performance over a training season in 12 years and underage-group swimmers: growth and kinematics effects

Abstract Aims: analyze kinematics, anthropometrics, and maturation during a training season in 12 y and underage-group swimmers, quantifying changes and estimating their contributions to the 200-m maximal front crawl time trial test (T200) (time trial/fixed distance), as an event representative of the swimming performance. Methods: Nineteen age-group swimmers (11 girls and 8 boys; age 10.0 ± 1.3 y and 10.6 ± 1.0 y) performed a T200 four times during the training season. Changes in kinematic and anthropometric variables throughout the season were calculated. We applied generalized estimating equations to compare the variables over the four experimental tests. Multiple linear regressions were applied to identify the most influential variables and the relative contribution of anthropometrics and kinematics to swimming performance of T200 at baseline (pre-season) and after (using delta values) each macrocycle. Results: Large improvements (d = 1.76) were observed in the T200's performance (from 85.5 ± 38.2 at pre-season to 175.2 ± 50.1 FINA points at the end season). A gender effect was not identified. Stroke rate, stroke length, and stroke index explained, respectively 59, 23, and 17% of the T200 performance changes along the season (R2 = 0.81; F = 26.9; p < 0.001; Durbin-Watson: 1.5). Anthropometric was not related to performance changes, with kinematic being the most determinant factor. Conclusion: Kinematical approaches must be carefully considered by coaches when planning 12 y and underage-group swimmers training programs.

Electromyographical and Physiological Correlation in Patient with Heart Disease

Abstract Background: Walking is an economic activity, the more efficient the mechanical contribution, the less metabolic energy is necessary to keep walking. Patients with chronic heart failure and heart transplant present peripheral musculoskeletal disorders, dyspnea, and fatigue in their activities. Objective: In this scenario, the present study sought to verify the correlations between metabolic and electromyographic variables in chronic heart failure, heart transplant patients, and healthy controls. Methods: Regression and correlation between cost of transport and electromyographic cost, as well as correlation between oxygen consumption and muscle coactivation in patients and controls at five different walking speeds have been performed, with alpha = 0.05. Results: Strong correlation values (r controls: 0.99; chronic heart failure: 0.92; heart transplant: 0.88) indicate a linear relationship between the cost of transport and electromyographic cost. Oxygen consumption was significantly correlated to muscle activation in all groups. Conclusion: These results suggested that dynamic muscle coactivation was an important factor, especially for CHF and HT. These data support the idea that peripheral muscle limitations play an important role in people with CHF and HT. These findings indicate a strong relation between metabolic and electromyographic variables. For chronic heart failure and heart transplant patients, it can help to explain some difficulties in daily activities and aid in physical rehabilitation.

Iniciação infantil ao polo aquático: fundamentação teórica e proposta de atividades / Children's initiation to the water polo: theoretical foundation and proposal of activities / Iniciación infantil al polo acuático: fundamento teórico y propuesta de actividades

Este estudo tem por objetivo propor diretrizes teórico-práticas para a construção de metodologias de ensino do Polo Aquático (PAq). Pretende apontar conteúdos indispensáveis na iniciação ao PAq para crianças (6 a 10 anos de idade) e apresentar atividades práticas para o processo de ensino-aprendizagem através de uma revisão narrativa de materiais pertinentes ao tópico na forma de ensaio. Clareza de lingua-gem, pertinência prática e representatividade do item foram avaliados por três especialistas e o coeficiente de validade de conteúdo geral foi de 0,91. A proposição de atividades baseadas em referenciais teóricos pode guiar os profissionais de educação física a ampliar o leque pedagógico de maneira sólida (AU).

This study aims to propose theoretical and practical guidelines for the construction of a teaching methodologies for Water Polo (PAq). It intends to point out indispensable contents in the initiation to PAq for children (6 to 10 years old) and to present practical activities for the teaching-learning process through a narrative review of materials pertinent to the topic in the form of an essay. Clarity of language, practical relevance and representativeness of the item were assessed by three experts and the overall content validity coefficient was 0.91. The proposition of activities based on theoretical references can guide physical education professionals to expand the pedagogical range in a solid way (AU).

Este estudio tiene como objetivo proponer pautas teóricas y prácticas para la construcción de metodologías de enseñanza para Water Polo (PAq). Busca señalar contenidos indispensables en la iniciación a PAq para niños (6 a 10 años) y presentar actividades prácticas para el proceso de enseñanza-aprendizaje a través de una revisión narrativa de materiales pertinentes al tema en forma de ensayo. Tres expertos evaluaron la claridad del lenguaje, la relevancia práctica y la representatividad del ítem y el coeficiente de validez de contenido general fue 0,91. La propuesta de actividades basadas en marcos teóricos puede orientar a los profesionales de la educación física a ampliar enormemente el abanico pedagógico (AU).

Iniciação infantil ao polo aquático: fundamentação teórica e proposta de atividades / Children's initiation to the water polo: theoretical foundation and proposal of activities / Iniciación infantil al polo acuático: fundamento teórico y propuesta de actividades

Este estudo tem por objetivo propor diretrizes teórico-práticas para a construção de metodologias de ensino do Polo Aquático (PAq). Pretende apontar conteúdos indispensáveis na iniciação ao PAq para crianças (6 a 10 anos de idade) e apresentar atividades práticas para o processo de ensino-aprendizagem através de uma revisão narrativa de materiais pertinentes ao tópico na forma de ensaio. Clareza de lingua-gem, pertinência prática e representatividade do item foram avaliados por três especialistas e o coeficiente de validade de conteúdo geral foi de 0,91. A proposição de atividades baseadas em referenciais teóricos pode guiar os profissionais de educação física a ampliar o leque pedagógico de maneira sólida.

This study aims to propose theoretical and practical guidelines for the construction of a teaching methodologies for Water Polo (PAq). It intends to point out indispensable contents in the initiation to PAq for children (6 to 10 years old) and to present practical activities for the teaching-learning process through a narrative review of materials pertinent to the topic in the form of an essay. Clarity of language, practical relevance and representativeness of the item were assessed by three experts and the overall content validity coefficient was 0.91. The proposition of activities based on theoretical references can guide physical education professionals to expand the pedagogical range in a solid way.

Este estudio tiene como objetivo proponer pautas teóricas y prácticas para la construcción de metodologías de enseñanza para Water Polo (PAq). Busca señalar contenidos indispensables en la iniciación a PAq para niños (6 a 10 años) y presentar actividades prácticas para el proceso de enseñanza-aprendizaje a través de una revisión narrativa de materiales pertinentes al tema en forma de ensayo. Tres expertos evaluaron la claridad del lenguaje, la relevancia práctica y la representatividad del ítem y el coeficiente de validez de contenido general fue 0,91. La propuesta de actividades basadas en marcos teóricos puede orientar a los profesionales de la educación física a ampliar enormemente el abanico pedagógico.

Biophysical Follow-up of Age-Group Swimmers During a Traditional Three-Peak Preparation Program.

Zacca, R, Azevedo, R, Ramos, VR, Abraldes, JA, Vilas-Boas, JP, Castro, FAdS, Pyne, DB, and Fernandes, RJ. Biophysical follow-up of age-group swimmers during a traditional three-peak preparation program. J Strength Cond Res 34(9): 2585-2595, 2020-The aim of this study was to quantify changes and contributions of bioenergetic, technique, and anthropometric profiles across a traditional 3-peak swimming season. Twenty-four age-group swimmers (11 boys: 15 years 6 months ± 1 year 1 month; 13 girls: 14 years 5 months ± 10 months) of equal maturational stage were monitored through a 400-m test in front crawl (T400). Bioenergetic, technique, and anthropometric characteristics were compared before and after macrocycles I, II and III. Sex interaction was verified only for amplitude of the fast oxygen uptake component and height (moderate). Multiple linear regressions and principal component analysis were used to identify the most influential variables and the relative contribution of each domain (bioenergetics, technique, and anthropometrics) to changes in swimming performance of T400. The relative contributions for the performance of T400 after macrocycles I, II, and III were, respectively, 6, 18, and 27% for bioenergetics, 88, 69, and 54% for technique, and 6, 13, and 20% for anthropometrics. Technique was the biggest contributor (71%) for changes in the performance of T400 over the training season, followed by bioenergetics (17%) and anthropometrics (12%). Technique played the main role during the competitive season, regardless of gradual increase in the contribution of bioenergetics and anthropometrics. Despite that, bioenergetics and technique are closely connected, thus a powerful and endurable metabolic base and cannot be overlooked. Changes and contribution of bioenergetics, technique, and anthropometrics on age-group swimmers' performance over a traditional 3-peak swimming season could be described by the T400 swimming test, providing a comprehensive biophysical overview of the main contributors to swimming performance.

The 400-m Front Crawl Test: Energetic and 3D Kinematical Analyses.

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p <0.05). Multiple linear regressions indicated that mean centre of mass speed and anaerobic alactic (kW) determined the 400-m test performance (R2=0.92). Even though the T400 is characterized by aerobic metabolism, the anaerobic alactic component cannot be negligible at this competition level.

Inter- and intra-rater reliability of swimming teachers with different skill levels, in different conditions, evaluating front crawl arm movement in non-expert swimmers

Abstract Aim: This study aimed (i) to test the inter-rater reliability of swimming teachers, (ii) to test the swimming teacher's discussion effect on inter-rater reliability and (iii) to verify the intra-rater swimming teacher's reliability. Method: Twenty-one learning swimmers (14.1 ± 5.1 years old) performed two 25-m front crawl courses at a comfortable speed without breathing between the sixth and 20-m, and had their displacements captured on film. Three swimming teachers with different academic backgrounds and skills evaluated the swimmer right upper limb using a 20-items checklist. In the 1st-step, teachers assessed 20-items and in 2nd-step discussed their particular evaluating criteria - selecting five items considered as the most relevant. The inter- and intra-rater reliability were tested using the Fleiss Kappa Coefficient. Results: In the 1st-step substantial reliability was found for item three and in movement descriptor for items three and 20. Nearly perfect reliability was found in the movement descriptor for item 13. In 2nd-step, moderate reliability was found only in the movement descriptor for item 20. Only the most experienced evaluator showed substantial intra-rater reliability for items four and 10 and moderate for item 20. Conclusion: The proposed discussion method did not cause the expected effect on inter-rater reliability. The swimming teacher with a higher degree and swimming skills showed better intra-rater reliability. Some items and movement descriptors proposed at the 20-items checklist can be used in practical settings.

Monitoring Changes Over a Training Macrocycle in Regional Age-Group Swimmers.

Our aim was to analyze physiological, kinematical and performance changes induced by swimming training in regional age-group athletes. Subjects (15.7 ± 2.2 years old) performed a 4 x 50-m front-crawl test at maximal velocity (10 s rest interval) in weeks 2, 4, 9 and 12 of a 15-week macrocycle. Descriptive statistics were used and the percentage of change and smallest worthwhile change (moderate, 0.6-1.2, and large, > 1.2) were measured. Lactate concentration in the third, seventh and twelfth minute of recovery decreased significantly between weeks 2-9 (14.1, 15.7 and 17.6%) and increased between weeks 9-12 (18.2, 18.6 and 19.8%), with the HR presenting only trivial variations during the training period. Stroke length showed a large decrease in the first 50-m trial between weeks 4-9 (6.2%) and a large increase between weeks 9-12 (3.1%). The stroke rate (in all 50-m trials) increased significantly between weeks 4-9 (3- 7%) and the stroke index had a moderate to large increase in the first and third 50-m trial (3.6 and 7.1%, respectively) between weeks 9-12. The overall time decreased by 1.1% between weeks 2-12, being more evident after week 4. We concluded that physiological, kinematical and performance variables were affected by the period of training in regional age-group swimmers.

Pedagogia da natação: análise das atividades realizadas em aulas para crianças / Swimming pedagogy: analysis of class activities for children / Pedagogía de la natación: análisis de las actividades realiza-das en clases para niños

Considerando a importância da diversidade de experiências motoras aquáticas para a melhor relação do indivíduo com o ambiente, o presente estudo teve como objetivo analisar as ativi-dades realizadas na iniciação de crianças à natação. Ao longo deste estudo foram identificadas e analisadas as atividades propostas por professores em 36 aulas, observadas de modo siste-mático. Dentre os resultados, das 36 aulas de 8 professores, 33 continham atividades de téc-nicas de nado, em um total de86 exercícios somados e realizados 134 vezes. Conclui-se que há a necessidade de se repensar a pedagogia da natação, pois a predominância no cenário atu-al é o ensino técnico dos quatro estilos competitivos antes mesmo do indivíduo se tornar in-dependente edemonstrar competência no meio aquático.

Considering the importance of the diversity ofaquatic motor experiences for the best relation-ship between the subject and the environment, the present study aimed to analyze the activi-ties performed in the initiation of children to swimming. Throughout this study, the activities proposed by teachers in 36 classes observed in a systematic way were identified and analyzed. Among the results, of the 36 classes, of eight teachers, 33 contained swimming technique ac-tivities, in 86 exercises added and performed 134 times. It is concluded that there is a need to rethink the pedagogy of swimming, because the predominance in the current scenario is the technical teaching of the four competitive strokes, before the individual becomes independent and demonstrate competence in the aquatic environment.

Considerando la importancia de la diversidad de experiencias motoras acuáticas para la mejor relación del individuo con el ambiente, el presente estudio tuvo como objetivo analizar las actividades realizadas en la iniciación de niños a la natación. A lo largo de este estudio fueron identificadas y analizadas las actividades propuestas por profesores en 36 aulas observadas de modo sistemático. Entre los resultados, de las 36 aulas, de ocho profesores, 33 contenían acti-vidades de técnica de nado, en un total de 86 ejercicios sumados y realizados 134 veces. Se concluye que hay la necesidad de repensar lapedagogía de la natación, pues la predominancia en el escenario actual es la enseñanza técnica de los cuatro estilos competitivos, antes de que el individuo se independice y demuestre competencia en el medio acuático.

Biomechanical analyses of synchronised swimming standard and contra-standard sculling.

Synchronised swimming involves a variety of sculling movements essential for body support and propulsion but its study is scarce. We aimed to biomechanically compare standard and contra-standard sculling techniques, and to observe the relationship between measures. Six synchronised swimmers performed two, 30 s maximal intensity, fully tethered standard and contra-standard sculling motions. Kinetic and kinematic data were obtained using a load-cell and underwater cameras, respectively. Force decreased along both techniques' bouts, but no differences in-between techniques were noted for any kinetic variables. Standard sculling presented a higher cycle rate and a lower elbow mean angle than the contra-standard sculling (2.4 ± 0.3 vs. 2.0 ± 0.2 cycles/s and 134.1 ± 5.8 and 141.5 ± 4.7°, p < 0.05). In the standard sculling, by removing and maintaining the variation between participants (r w and r, respectively), the absolute mean force was directly related with cycle rate (r w  = 0.60) and wrist angular velocity during flexion (r = 0.82), while in the contra-standard condition the force was inversely associated with wrist mean angle (r = -0.95) and directly with hand speed (r w  = 0.76), and elbow angular velocity (r w  ≈ 0.60). Therefore, technique learning and training require different attention by coaches and swimmers.

Sampling procedures and calculation for sample size determination: criteria and methods adopted in theses and dissertations in Human Movement Sciences - a descriptive study / Processos de amostragem e cálculo para determinação do tamanho da amostra: critérios e métodos adotados em teses e dissertações em Ciências do Movimento Humano - um estudo descritivo

Abstract Quantitative monographic studies systematically use inferential statistical procedures to test hypotheses. For this purpose, sampling procedures and sample sizes need to be adequate for the proposed procedures. The aim of this study was to identify the sample selection methods, as well as the performance and types of calculation to determine the sample size adopted in theses and dissertations developed in a graduate program in the field of Physical Education. Theses and dissertations defended between 2003 and 2013 were obtained through digital repository. Only quantitative studies were included, in which the following issues were analyzed: (1) sample selection criteria; (2) presence of sample calculation; (3) calculation type to estimate sample size. A total of 199 studies were included. Of these, 6% (n=11) used probabilistic methods for sample selection and 3% (n=6) used animal models. As for the accomplishment of sample calculations, 36% (n=72) studies reported having adopted this procedure. Of studies that performed sample calculations, 25% (n=18) used predictive equations, 67% (n=48) considered methods with statistical power as their base, 3% (n=2) used confidence interval, 4% (n=3) did not mention the method and 1% (n=1) was based on the type of statistical test to be used later. Non-probabilistic sampling methods predominate for the selection of subjects; most studies do not report adopting calculations to estimate sample size and, among those that reported the use, the models that consider statistical power as the main criterion are predominant.

Resumo Trabalhos monográficos quantitativos utilizam, sistematicamente, procedimentos estatísticos inferenciais para testar hipóteses. Para tanto, é necessário que os procedimentos de amostragem e os tamanhos amostrais estejam adequados aos procedimentos propostos. Objetivou-se identificar os métodos de seleção amostral, bem como a realização e os tipos de cálculo para determinação do tamanho amostral adotados em teses e dissertações desenvolvidas em um programa de pós-graduação no campo da Educação Física. As teses e dissertações, defendidas entre 2003 e 2013, foram obtidas via repositório digital. Foram incluídos apenas estudos de caráter quantitativo, nos quais analisou-se: (1) critério para seleção amostral; (2) presença de cálculo amostral; (3) tipo de cálculo para estimativa do tamanho amostral. Foram incluídos 199 trabalhos. Dentre estes, 6% (n=11) usaram métodos probabilísticos para seleção amostral e 3% (n=6) usaram amostra animal. Quanto à realização de cálculo amostral 36% (n=72) dos trabalhos relatam ter adotado. Dos estudos que citam ter realizado cálculos, 25% (n=18) usaram equações preditivas, 67% (n=48) consideraram métodos com o poder estatístico como base, 3% (n=2) usaram o intervalo de confiança, 4% (n=3) não citam o método e 1% (n=1) baseou-se no tipo de teste estatístico a ser usado posteriormente. Os métodos de amostragem não-probabilísticos predominam para a seleção dos sujeitos; grande parte dos estudos não relata adotar cálculos para a estimativa do tamanho amostral e dentre aqueles que citam utilizar, os modelos que consideram o poder estatístico como principal critério são predominantes.

Influence of hand paddles and fins on blood lactate, heart rate and perceived exertion behavior / Influência do uso de palmares e nadadeiras no comportamento do lactato sanguíneo, da frequência cardíaca e do esforço percebido

Abstract - One of the great challenges for swim coaches is proper control of the training intensity. This issue is more complex when using equipment such as paddles and fins. Among intensity control parameters, blood lactate concentration is the standard for monitoring metabolic responses, and heart rate and perceived effort are practical and inexpensive methods. The aim of this study was to compare blood lactate concentration ([LA]), heart rate (HR) and rate of perceived exertion (RPE) in swimming training series without equipment and with paddles and fins. We evaluated 11 swimmers on three different days during sessions in a series of 12 repetitions of 50 m in front crawl. The first session was performed without equipment, maintaining perception exertion at 15 (15 points) of the 6-20 point Borg scale. In the second and third sessions, athletes should swim in the series with: (i) paddles and (ii) fins, at the same swimming speed of the series without equipment, in random order. [LA], HR and RPE at rest (after warm-up and before swimming series) and after the sixth and 12th repetitions were measured and compared. The mean speed for all series was 1.30 ± 0.13 m.s-1; fins and paddles presented lower final [LA] (respectively, 5.9 ± 0.3 and 8.1 ± 0.4 mmol.l-1) and HR values (respectively, 161.1 ± 15, 5 161.1 and 170.3 ± 13.3 170.3 bpm) in comparison to series without equipment (respectively, 10.8 ± 0.7 mmol.l-1 and 178.2 ± 4.3 bpm). Fins had lower final RPE values (12.5 ± 0.6 points) in relation to series without equipment (15.8 ± 0.2 points) and similar values in relation to swimming with paddles. Swimming series with equipment produced lower physiological demands in relation to swimming without equipment if performed at the same swimming speed as swimming without equipment.

Resumo Um dos grandes desafios para treinadores de natação é o adequado controle da intensidade de treino. Essa questão é mais complexa quando utilizados equipamentos como palmares e nadadeiras. Dentre os parâmetros de controle de intensidade, a concentração sanguínea de lactato [LA] é padrão para acompanhamento de respostas metabólicas, e a frequência cardíaca (FC) e o esforço percebido (EP) são métodos práticos e baratos. Esse estudo teve como objetivo comparar a concentração sanguínea de lactato, a frequência cardíaca e o esforço percebido em série de treinamento de natação sem equipamentos, com palmares ou com nadadeiras. Foram avaliados 11 nadadores em três diferentes dias durante série de 12 repetições de 50 m nado crawl. A primeira foi realizada sem equipamentos mantendo a percepção relativa ao escore 15 da escala de 6 a 20 pontos de Borg. A segunda e terceira séries os atletas realizavam (i) utilizando palmares e (ii) utilizando nadadeiras, na mesma velocidade de nado da série sem equipamentos, em ordem aleatória. Foram mensuradas e comparadas [LA], FC e EP nos momentos repouso (pós-aquecimento e antes da série), após a sexta e a 12ª repetições. A velocidade média para todas as séries foi de 1,30 ± 0,13 m.s-1; nadadeiras e palmares apresentaram menores valores finais de [LA] (respectivamente, 5,9 ± 0,3 e 8,1 ± 0,4 mmol.l-1) e de FC (respectivamente, 161,1 ± 15,5 e 170,3 ± 13,3 bpm) em relação ao nado sem equipamentos (respectivamente, 10,8 ± 0,7 mmol.l-1 e 178,2 ± 4,3 bpm). O nado com nadadeiras apresentou menores valores finais de EP (12,5 ± 0,6 pontos) em relação ao nado sem equipamentos (15,8 ± 0,2 pontos) e similares valores em relação ao nado com palmares. Séries de natação com equipamentos produzem menores demandas fisiológicas em relação ao nado sem equipamentos se realizadas na mesma velocidade de nado que o nado sem equipamentos.

Electromyography and economy of walking in chronic heart failure and heart transplant patients.

Background Patients with chronic heart failure frequently report intolerance to exercise and present with changes in walk pattern, but information about heart transplant patients is lacking. Alterations of the gait pattern are related to interaction changes between the metabolism, neurological system and the mechanical demands of the locomotor task. The aim of this study was to investigate the electromyographic cost, coactivation and cost of transport of walking of chronic heart failure and heart transplant patients. Design This research was of an exploratory, cross-sectional design. Methods Twelve chronic heart failure patients, twelve healthy controls and five heart transplant patients participated in the study. Electromyographic data and oxygen uptake were collected simultaneously at five walking speeds. Results In the experimental groups, the electromyographic cost, percentage of coactivation in the leg and cost of transport were higher than in controls. The electromyographic cost was in line with the cost of transport. The minimum electromyographic cost matched with the self-selected walking speed in controls, while in chronic heart failure and heart transplant patients, it was reached at speeds higher than the self-selected walking speed. Conclusion The largest postural isometric activation and antagonist activation resulted in the highest metabolic demand. These findings are of great clinical relevance because they support the concept that interventions in order to improve the muscle performance in these patients can increase the self-selected walking speed and therefore the metabolic economy of walking.