Abstract Drag crisis has been described as a drop in the drag coefficient (Cd). This procedure was lately assessed in able-bodied cyclists in time trial position by computational fluid dynamics (CFD). Therefore, the aim of this study was to assess the phenomenon of the drag crisis by computer fluid dynamics in transradial and transtibial amputee cyclists in the upright position. A male elite-level cyclist was recruited for this research. The subject was scanned (3D geometry with a 3D Scan) with his competition bicycle, helmet, suit, and shoes. Consequently, transradial and transtibial 3D models were created editing the able-bodied 3D model. To perform the CFD analyses, a domain measuring 7 x 2.5 x 2.5 m (length, width and height, respectively) was created around each bicycle-cyclist model. The domains were meshed with more than 42 million elements. Numerical simulations by CFD were performed in fluent numerical for speeds between 1 m/s and 13 m/s, with increments of 1 m/s. The total Cd decreased with speed. It ranged from 0.84 to 0.55 in the able-bodied, 0.86 to 0.64 in the transradial and 0.90 to 0.61 in the transtibial. The drag crisis phenomenon was observed between 1m/s and 4m/s in all models.

Abstract The aim of this study was to evaluate maximum voluntary contraction through surface electromyography in stabilizer shoulder muscles, as well as the clinical evaluation of shoulder injury in the pre, post, and detraining stages of specific training in child swimmers. Twelve competitive swimmers volunteered for this study. Anthropometric measurements, clinical examination, electromyography (with Delsys® data acquisition system), and pain intensity levels were performed. Clinical examination and EMG data were compared using repeated-measures ANOVA with Bonferroni correction pre, post, and after detraining. The intervention program lasted for 12 weeks. The pain group presented higher pain intensity values compared to the post-intervention program. Most of the tests presented lower values at the detraining compared to the baseline. After the intervention, pain levels significantly decreased in five tests. Muscle strengthening work is highly recommended because it improves the swimmer’s shoulder performance, reducing injuries and decreasing pain intensity after 12 weeks of intervention.

ABSTRACT This study aimed to verify the impact of two learn-to-swim programs, implemented for 12 weeks, in age school Brazilian children's aquatic readiness and motor coordination. Thirty-one children aged 7-9 years old (mean± SD 8.00± 0.86 years) were randomly divided into two different experimental groups. One was submitted to lessons mainly focused on basic skills development (BS), and the other was mainly focused on the formal skills of swimming techniques (FS). The aquatic readiness (17 skills) and the motor coordination (Körperkoordinationstest Für Kinder test) were evaluated before and after the interventions. After 12 weeks, the total score of the swimming skills was different between groups (F= 24.19, p< 0.01, ηp2= 0.46), changing from 34.35± 9.22 to 50.18± 8.49 points (p< 0.01, d= 2.60) in the BS and from 36.00± 5.86 to 42.64± 7.46 points in the FS (p< 0.01, d= 1.88). Leg kicking with breath control at ventral and dorsal body position, feet-first entry and deep-water immersion were significantly higher after the training in the BS. The motor coordination scores increased in both the BS (135.57± 37.45 to 172.64± 33.17, p< 0.01, d= 2.11) and FS (130.18± 37.71 to 162.71± 40.40, p< 0.01, d= 1.41). These results showed that both swimming practices improved aquatic readiness and motor coordination, with higher aquatic competence after the lessons that mainly focused on basic skills development.

ABSTRACT The present study on the motor development of children in the first months of life aimed to verify the relationship between Motor Skills and Age, and the relationship between Global and Fine motor skills in children from 12 to 46 months. For this purpose, we developed a transversal quantitative study, with a sample of 405 children between the ages of 12 and 46 months of both genders. The instruments used in the study were the Peabody Developmental Motor Scales-2 (PDMS-2). Overall, the results indicate that there is a tendency for positive (mostly moderate and low) positive correlations between the variables Age, Global Motor Skills and Fine Motor Skills, emphasizing the moderate positive correlation (p≤0.05; r2=0.265; 0.5≤ r ≤ 0.7) between Age and Fine Motricity in turn a small positive correlation (p≤0.05; r2=0.217; 0.1≤ r ≤ 0.3) between Age and Global Motricity. We can thus see an improvement of these abilities as children grow, emphasizing better results in Fine Motor.

RESUMO O presente estudo sobre o desenvolvimento Motor da criança nos primeiros meses de vida, teve como objetivo verificar a relação entre as Habilidades Motoras e a Idade, e a relação entre as habilidades motoras Globais e Finas em crianças dos 12 aos 46 meses. Para o efeito, desenvolvemos um estudo de natureza quantitativa, com uma amostra de 405 crianças com idades compreendidas entre os 12 e os 46 meses, de ambos os géneros. Os instrumentos usados no estudo foram as Peabody Developmental Motor Scales-2 (PDMS-2). Em termos globais os resultados indicam que existe uma tendência para correlações positivas (maioritariamente moderadas e baixas) entre as variáveis Idade, Habilidades Motoras Globais e Habilidades Motoras Finas, salientando a correlação positiva moderada (p≤0.05; r2=0.265; 0.5≤ r ≤0.7) entre a Idade e a Motricidade Fina e por sua vez uma correlação positiva pequena (p≤0.05; r2=0.217; 0.1≤ r ≤ 0.3) entre a Idade e a Motricidade Global. Podemos assim contatar, uma melhoria destas habilidades à medida que as crianças vão crescendo, salientando melhores resultados na Motricidade Fina.

RESUMEN El presente estudio sobre el desarrollo motor de los niños en los primeros meses de vida tuvo como objetivo verificar la relación entre las habilidades motoras y la edad, y la relación entre las habilidades motoras globales y finas en niños de 12 a 46 meses. Para ello, desarrollamos un estudio de naturaleza tranversal cuantitativa, con una muestra de 405 niños de edades comprendidas entre los 12 y los 46 meses, de ambos géneros. Los instrumentos utilizados en el estudio fueron las Peabody Developmental Motor Scales-2 (PDMS-2). En términos globales los resultados indican que existe una tendencia a correlaciones positivas (mayoritariamente moderadas y bajas) entre las variables Edad, Habilidades Motoras Globales y Habilidades Motoras Finas, resaltando la correlación positiva moderada (p≤0.05, r2=0.265, 0.5≤ r ≤ 0.7) entre la Edad y la Motricidad Fina a su vez una pequeña correlación positiva (p≤0.05, r2=0.217, 0.1≤ r ≤ 0.3) entre la Edad y la Motricidad Global. Podemos así constatar, una mejora de esas habilidades a medida que los niños crecen, destacando mejores resultados en la Motricidad Fina.

ABSTRACT Objective: The aim of the present study was to validate the Basic Psychological Need Satisfaction and Frustration Scale in Exercise for fitness instructors. Methods: Data from 477 exercise professionals (319 males, 158 females) was collected. Results: CFA supported the adapted and validated six-factor model: [χ2(237) = 1096.796, χ2/df= 4.63; B-S p < .001, CFI = .930, TLI = .918, SRMR= .0366, RMSEA = .079 (CI90% = .069, .089)], assessing satisfaction and frustration of basic psychological needs in Portuguese exercise professionals. Moreover, the analysis revealed acceptable composite reliability, and construct validity of the adapted version. Results revealed nomological validity, as well as invariance between male and female. No differences were found across latent means, and magnitude effects were trivial between gender. Conclusion: These results support the use of the adapted scale in exercise professionals, showing measurement invariance between gender. This scale is able to measure how exercise professionals experience satisfaction and frustration of basic needs when prescribing exercise to individuals in fitness context.

RESUMO Objetivo: O objetivo deste estudo consistiu na validação do Basic Psychological Need Satisfaction and Frustration Scale in Exercise em instrutores de fitness. Métodos: Recolhemos dados de 477 profissionais de exercício físico (319 masculino, 158 feminino). Resultados: A análise CFA suporta o modelo de 6-factores adaptado e validado: [χ2(237) = 1096.796, χ2/df= 4.63; B-S p < .001, CFI = .930, TLI = .918, SRMR= .0366, RMSEA = .079 (CI90% = .069, .089)], avaliando a satisfação e frustração das necessidades psicológicas básicas em instrutores profissionais portugueses de exercício físico. Além disso, a análise revela fiabilidade compósita aceitável e validade dos construtos da versão adaptada. Os resultados revelam validade nomológica, bem como invariância entre sexo masculino e feminino. Não foram encontradas diferenças entre as médias latentes, e a magnitude dos efeitos foi trivial entre géneros. Conclusão: Estes resultados suportam o uso desta escala adaptada em profissionais do exercício físico, mostrando ser invariante entre géneros. Esta escala é capaz de medir como os técnicos profissionais de exercício físico experienciam a satisfação e frustração das necessidades básicas aquando da prescrição de exercício físico para clientes de exercício no contexto do fitness.

RESUMEN Objetivo: El objetivo del presente estudio fue validar la Escala de Satisfacción y Frustración de Necesidades Psicológicas Básicas en el Ejercicio para instructores de ejercicio físico. Métodos: Se recopilaron datos de 477 profesionales del ejercicio (319 hombres, 158 mujeres). Resultados: CFA apoyó el modelo de seis factores adaptado y validado: [χ2 (237) = 1096.796, χ2 / df = 4.63; B-S p <.001, CFI = .930, TLI = .918, SRMR = .0366, RMSEA = .079 (CI90% = .069, .089)], evaluando la satisfacción y la frustración de las necesidades psicológicas básicas en los profesionales del ejercicio portugués. Además, el análisis reveló una validez en la confiabilidad compuesta, constructo y nomológica aceptables de la versión adaptada, así como invariabilidad entre hombres y mujeres. No se encontraron diferencias entre las medias latentes, y los efectos de magnitud fueron triviales entre los géneros. Conclusión: estos resultados apoyan el uso de la escala adaptada en los profesionales del ejercicio, que muestran la invariancia de la medición entre los géneros. Esta escala es capaz de medir cómo los profesionales del ejercicio experimentan la satisfacción y la frustración de las necesidades básicas, y cómo regulan los comportamientos interpersonales.

Resumo O objetivo deste estudo foi a tradução e validação do Physical Activity Enjoyment Scale, a partir da versão de Mullen et al., numa amostra de atletas portugueses e a invariância entre gêneros, desportos de natureza e natação, bem como, comprovar critérios de validade externa através da versão portuguesa do BRSQ. Participaram neste estudo 1032 atletas (273 desporto natureza; 759 natação), com uma média de 18,95 ± 6,59 anos de idade. Os dados foram analisados através de análise fatorial confirmatória (método da máxima verosimilhança), análise multigupos (invariância entre grupos) e análise correlacional. Os resultados suportam a adequação dos modelos (1 fator, oito itens), para cada uma das amostras (geral. χ2=181,96, p=<0,01, df=20, SRMR=0,04, NNFI=0,94, CFI=0,96, RMSEA=0,07, RMSEA 90% IC=0,06-0,08; masculino: x2=113,27, p=<0,01, df=20, SRMR=0,035,NNFI=0,95, CFI=0,97, RMSEA=0,07, RMSEA 90%IC=0,06-0,08;feminino: χ2=67,59,p=<0,01, df=20, SRMR=0,03,NNFI=0,94, CFI=0,96, RMSEA=0,07, RMSEA90% IC=0,06-0,09; desporto de natureza: χ2=42,32, p=0,02, df=20, SRMR=0,037, NNFI=0,96, CFI=0,98, RMSEA=0,06, RMSEA90%IC=0,04-0,08; natação:χ2=130,14,p=<0,001, df=20, SRMR=0,04, NNFI=0,943, CFI=0,.96, RMSEA=0,07, RMSEA 90% IC=0,06-0,08), bem como, revelou ser invariante em função dos gêneros e das modalidades (∆CFI<0,01). O divertimento correlacionou-se positivamente com regulação identificada (r=0,82), regulação integrada (r=0,62) e motivação intrínseca (r=0,90), e negativamente com a amotivação (r=-0,25), regulação externa (r=-0,42) e regulação introjetada (r=-0,38). Estes resultados permitem-nos afirmar que a tradução e adaptação do PACES, pode ser utilizada com elevado grau de validade e fiabilidade na avaliação do divertimento em futuros estudos, suprimindo uma lacuna existente.

Abstract The aim of this study was to translate and validate of the Physical Activity Enjoyment Scale (PACES) from Mullen et al. version in Portuguese athletes, invariance across genders and nature sports and swimming, as well as, external validity, through the Portuguese version of BRSQ.Athletes (n=1032; 273 nature sports, 759 swimming) with an average age of 18,95 ± 6,59 years participated in this study. Confirmatory factor analysis (maximum likelihood), multigroup analysis (measurement invariance) and correlation analysis were used for data analyzed. Results supported the suitability of the models (one factor which eight items) showing an adequate fit to the data in each sample (general:χ2=181,96, p=<0,01, df=20, SRMR=0,04, NNFI=0,94, CFI=0,96, RMSEA=0,07, RMSEA 90% IC=0,06-0,08; male:χ2=113,27, p=<0,01, df=20, SRMR=0,04, NNFI=0,95, CFI=0,97, RMSEA=0,07, RMSEA 90% IC=0,06-0,08; female: χ2=67,59, p=<0,01, df=20, SRMR=0,03, NNFI=0,94, CFI=0,96, RMSEA=0,07, RMSEA 90% IC=0,06-0,09; nature sports: χ2=42,32, p=0,02, df=20, SRMR=0,037, NNFI=0,96, CFI=0,98, RMSEA=0,06, RMSEA 90% IC=0,04-0,08; swimming: χ2=130,14, p=<0,01, df=20, SRMR=0,04, NNFI=0,94, CFI=0,96, RMSEA=0,07, RMSEA 90% IC=0,06-0,08), as well as, were invariant across genders and nature sports and swimming (∆CFI<0,01). Enjoyment was, on the one hand, found to be positively and significantly correlated with identified regulation (r=0,82), integrated regulation (r=0,62) and intrinsic motivation (r=0,90). On the other, it was negatively and significantly correlated with amotivation (r=-0,25) and external and introjected regulation (r=-0,42; -0,38), respectively. Those findings allow concluding that PACES can be used to measure enjoyment in the future studies, thus filling an existing gap to date.

De entre as técnicas não invasivas de determinação do limiar anaeróbio, o método da determinação da velocidade crítica tem merecido grande atenção, nomeadamente no âmbito da avaliação e controlo do treino em natação. Neste sentido, o objetivo do presente artigo foi efetuar uma revisão da literatura do tipo qualitativa acerca do significado do parâmetro velocidade crítica e sua aplicação à natação. Foram abordadas questões relativas à origem e definição do conceito de velocidade crítica, às metodologias de determinação mais comuns, bem como uma breve referência ao conceito de velocidade crítica anaeróbia. A velocidade crítica é sugerida como um parâmetro não invasivo de avaliação do desempenho aeróbio e de predição do limiar anaeróbio de nadadores, independentemente do nível desportivo. As principais vantagens deste indicador resultam da facilidade de aplicação e análise num elevado número de nadadores, sem a necessidade da utilização de equipamentos dispendiosos ou de recolha de sangue. Aponta-se como uma ferramenta útil no mecanismo de prescrição e controlo de cargas de treino por meio de resultados em condições experimentais ou recorrendo a tempos obtidos durante as competições. A descriminação dos valores de velocidade crítica entre nadadores com diferentes perfis metabólicos (velocistas versus fundistas) e ainda a sua aplicabilidade em regime anaeróbio são aspetos que ainda carecem de um maior entendimento.

Considering several non-invasive techniques to determine anaerobic threshold, the determination of critical velocity has been the topic of interest of several studies, namely under the scope of evaluation and control of training in swimming. Therefore, the aim of this study was to conduct a literature review regarding the meaning of the critical velocity and its application in swimming. The concept origins, the critical velocity definition and the most common methodologies for its determination were addressed. The critical velocity has been known as a non-invasive measure that represents the aerobic capacity and is similar to anaerobic threshold in swimmers, independent from the competitive level. Major advantages are the easily application in field interventions without having to use heavy methods/blood samples collection, and the possibility to comprise larger samples of swimmers for further analysis. The critical velocity is a useful tool for training load prescription and seasonal monitorization that can be assessed by mean of experimental approach or using race times in competition context. The discrimination about critical velocity values regarding swimmers with different metabolic profiles and the use of the concept within the anaerobic context are aspects that need further understanding.

The aim of this study was to analyze the effect of depth on the hydrodynamic drag coefficient during the passive underwater gliding after the starts and turns. The swimmer hydrodynamics performance was studied by the application of computational fluid dynamics (CFD) method. The steady-state CFD simulations were performed by the application of k - omega turbulent model and volume of fluid method to obtain two-phase flow around a three-dimensional swimmer model when gliding near water surface and at different depths from the water surface. The simulations were conducted for four different swimming pool size, each with different depth, i.e., 1.0, 1.5, 2.0 and 3.0 m for three different velocities, i.e., 1.5, 2.0 and 2.5 m/s, with swimmer gliding at different depths with intervals of 0.25 m, each starting from the water surface, respectively. The numerical results of pressure drag and total coefficients at individual average race velocities were obtained. The results showed that the drag coefficient decreased as depth increased, with a trend toward reduced fluctuation after 0.5m depth from the water surface. The selection of the appropriate depth during the gliding phase should be a main concern of swimmers and coaches.

The purpose of this study was to analyse the effect of wearing a swimsuit on swimmer's passive drag. A computational fluid dynamics analysis was carried out to determine the hydrodynamic drag of a female swimmer's model (i) wearing a standard swimsuit; (ii) wearing a last generation swimsuit and; (iii) with no swimsuit, wearing light underwear. The three-dimensional surface geometry of a female swimmer's model with different swimsuit/underwear was acquired through standard commercial laser scanner. Passive drag force and drag coefficient were computed with the swimmer in a prone position. Higher hydrodynamic drag values were determined when the swimmer was with no swimsuit in comparison with the situation when the swimmer was wearing a swimsuit. The last generation swimsuit presented lower hydrodynamic drag values, although very similar to standard swimsuit. In conclusion, wearing a swimsuit could positively influence the swimmer's hydrodynamics, especially reducing the pressure drag component.

Os objetivos deste estudo foram: i) caracterizar o nado submáximo e máximo do ponto de vista cinemático; ii) verificar a influência das variáveis cinemáticas na prova máxima de 200 metros crawl. Nove nadadores de elite nacionais realizaram dois testes: um submáximo, descontínuo de intensidade progressiva; outro máximo, que consistiu em uma simulação de uma prova de 200 m crawl. Foram estudados os parâmetros cinemáticos gerais da mecânica da braçada, a duração de cada fase do ciclo gestual, a velocidade do centro de massa e a variação intracíclica da velocidade horizontal. Verificaram-se diferenças cinemáticas significativas da frequência gestual, velocidade de deslocamento do centro de massa, duração total do ciclo gestual, duração da ação subaquática propulsora e da velocidade do centro de massa na fase de recuperação entre os testes. Identificou-se associações significativas entre o teste máximo e algumas variáveis cinemáticas como a velocidade do centro de massa e índice de nado.

The main aims of this study were i) to perform a kinematic characterization of sub and maximal swimming speed; ii) to investigate the associations between the kinematic profiles and the 200 m front crawl style. Nine national level male swimmers performed two speed tests: a submaximal discontinuous speed trial of progressive speed intensity, and a maximal one, simulating a 200 m front crawl style. The stroke general kinematic parameters, the phases duration of the stroke cycle, the velocity of the centre of mass and the intra cyclic variation of the horizontal velocity were herein studied. Significant kinematic differences in relation to stroke rate, horizontal velocity of the centre of mass, total cycle duration, absolute and relative duration of the propulsive sub aquatic action and the velocity of the centre of mass during the arms recovery were compared between the speed tests. Significant correlations between the performance in the maximal speed and some kinematic variables were observed.

Considerando que alguns estudos sugerem que desequilíbrios musculares dos rotadores dos ombros estão relacionados com dores e lesões na articulação e que não existem dados normativos para jovens nadadores, o objetivo deste estudo foi: i) caracterizar o equilíbrio e fadiga musculares bem como o perfil de força isocinética dos rotadores dos ombros em nadadores jovens; ii) comparar os resultados entre nadadores com jovens não praticantes; iii) contribuir para a criação de dados normativos de rácios unilaterais dos rotadores do ombro. Foi avaliada a força isocinética com ações concêntricas dos rotadores e respectivos rácios unilaterais (quociente entre torque dos rotadores externos e internos) em 60 nadadores (idade: 14,55 ± 0,5 anos; massa corporal: 61,16 ± 7,08 kg) e 60 não praticantes (idade: 14,62 ± 0,49 anos; massa corporal: 60,22 ± 10,01 kg). Com um dinamômetro isocinético (Biodex System 3), avaliou-se na posição de sentado (90º de abdução e de flexão do cotovelo), às velocidades angulares de 60º.s-1 e 180º.s-1. Os resultados dos índices de fadiga não revelaram diferenças entre grupos. Os nadadores apresentaram rácios unilaterais entre os 73,39±17,26% no membro dominante (MD) e 77,89±15,23% no membro não dominante (MND), para avaliações efetuadas a 60º.s-1; a 180º.s-1, obtivemos resultados entre 74,77±13,99% para MD e 70,11±14,57% para MND. Os nadadores apresentaram um maior desequilíbrio muscular, sendo a capacidade de produção de força dos rotadores internos (significativamente superior nos nadadores) o que os distingue do grupo de não praticantes.

Considering that some studies suggest that shoulder rotators muscle imbalances are related to joint pain and injury, and that there are no normative data for young swimmers, the aim of this study was: i) to describe the muscle balance, fatigue and isokinetic strength profile of the shoulder rotators in young swimmers; ii) to compare the results between swimmers and a group of young non-practitioners; iii) to contribute to the acquisition of normative data of unilateral ratios of shoulder rotators. We evaluated the shoulder rotators concentric strength and unilateral ratios (ratio between torque of external and internal rotators) of 60 swimmers (age: 14.55 ± 0.5 years old; body mass: 61.16 ± 7.08 kg) and 60 non-practitioners (age: 14.62 ± 0.49 years old; body mass: 60.22 ± 10.01 kg). The evaluation was performed in the sitting position (90º abduction and elbow flexion) at 60º.s-1 and 180º.s-1 angular speeds using an isokinetic dynamometer (Biodex System 3). The results of the fatigue ratios revealed no differences between the groups. Swimmers showed unilateral ratios of 73.39 ± 17.26% in the dominant limb (DL) and 77.89 ± 15,23% in the non-dominant limb (NDL) for assessments at 60º.s-¹. At 180º.s-1, ratios were 74.77± 13.99% for DL and 70.11 ± 14.57% for NDL. Swimmers presented greater muscle imbalance, and differed from non-practitioners in the ability to produce power with the internal rotators, which was significantly higher in the former group.

O objectivo do estudo foi desenvolver e validar equações preditivas da área de secção transversa do tronco humano, Os modelos foram desenvolvidos para o sexo masculino e de acordo com o nível competitivo, A amostra foi composta por 152 sujeitos, todos praticantes de Natação Pura desportiva, com idades entre os 10 e os 32 anos de idade, Para o desenvolvimento dos modelos foi utilizado um grupo de sujeitos para estimar a equação e um outro para validar. Foram avaliadas as seguintes características antropométricas: (i) massa corporal; (ii) estatura; (iii) diâmetro bi-acromial; (iv) diâmetro tóraco-sagital; (v) perímetro peitoral e (vi) área de secção transversal do tronco. Os modelos preditivos foram desenvolvidos através de análise de regressão linear múltipla passo-a-passo e num dos casos, com recurso ao nível competitivo enquanto variável dummy. Todos os modelos desenvolvidos incluíram como variáveis independentes o diâmetro tóraco-sagital e o perímetro peitoral (0,32 ≤ R² ≤ 0,48; P < 0,01). No processo de validação entre as áreas de secção transversal do tronco medida e estimada, não se verificaram diferenças significativas entre valores médios (P > 0,05), as regressões lineares simples foram moderadas (0,23 ≤ R² ≤ 0,39; 0,01 ≤ P ≤ 0,001) e o critério de Bland Altman foi em todos os casos cumprido. Pode concluir-se que os modelos desenvolvidos para nadadores masculinos, e de acordo com o nível competitivo, predizem com validade a área de secção transversa do tronco de nadadores.

The objective of this study was to develop and validate predictive equations of the cross-sectional area of the human trunk. The models were developed for males according to their level of expertise. The sample comprised 152 male subjects, all of them with a background in competitive or recreational swimming. Their ages ranged between 10 and 32 years. Two different groups of subjects were used to estimate and validate the equation. The following anthropometric characteristics were assessed: (i) body weight, (ii) height, (iii) biacromial diameter, (iv) sagittal thoracic diameter, (v) chest circumference, and (vi) cross-sectional area of the trunk. Predictive models were developed using stepwise multiple linear regression analysis. One of the models used level of expertise as a dummy variable. All models included sagittal thoracic diameter and chest circumference as independent variables (0.32 ≤ R² ≤ 0.48; P < 0.01). The validation process of the measured and estimated cross-sectional area of the trunk did not reveal any significant differences between the mean values (P > 0.05). The simple linear regressions were moderate (0.23 ≤ R² ≤ 0.55; 0.01 ≤ P ≤ 0.001), and the Bland-Altman criterion was met in all cases. Therefore, our findings suggest that the models developed for male swimmers according to their level of expertise are able to provide a valid prediction of the cross-sectional area of the trunk.

O objetivo do presente estudo foi comparar os efeitos do treino de força (TF) e do respectivo destreinamento entre dois modelos de periodização do volume (linear - ML; não linear - MNL) em jovens voleibolistas. A amostra foi composta por 12 jovens do sexo masculino jogadores de voleibol (17.1 ± 0.5 anos), divididos em dois grupos homogêneos. Os resultados sugerem que 8 semanas de TF induzem modificações significativas nos indicadores da força, independentemente do modelo de periodização utilizado. Contudo, o MNL parece menos eficaz no desenvolvimento da força explosiva em habilidades motoras específicas (salto vertical). Os resultados indicam que 4 semanas de destreinamento são suficientes para provocarem perdas significas na força muscular em jovens voleibolistas. O destreinamento de um ML induz a perdas significativas na força explosiva do trem superior (lançamento de bola medicinal) e inferior (salto vertical), enquanto que no MNL parece diminuir significativamente a força dinâmica máxima (supino) e o desempenho no salto vertical.

This study aimed to compare the effects of strength training (ST) and detraining (DT) of two volume periodization models (linear - LM; non linear - NLM) in young male volleyball players. 12 volleyball players (17.1±0.5 years old) were randomly divided into two groups. The results of the present study suggest that 8 weeks of ST induce changes in the indicators of increased maximal strength and explosive strength, regardless of models used. However, the NLM seems less effective in the development of explosive strength in specific motor skills (vertical jump). As for DT, this study suggests that 4 weeks is sufficient to cause significant losses as an indicator of release between the two models of training. The LM induces significant losses in the explosive strength of the upper (medicine ball throwing) and lower body (vertical jump), while the NLM suggests higher losses in the maximum strength (train top) besides the jumping ability.