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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.

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Biomechanical and coordination measurements are useful tools to assess swimming performance. Regarding Paralympic swimming, function and technique make these measurements complex. The aim of this study was to perform a systematic review of studies on biomechanics, coordination and performance in disabled swimmers following swimming protocols and in competitions. Data sources: PubMed, EMBASE, ISI Web of Knowledge, SPORTDiscus and Academic Search Premier. We selected complete studies, published until June 2018. Eighteen studies satisfied the inclusion criteria and were selected for qualitative analysis; nine of these were included in the meta-analysis. Swimming speed and stroke length increase with less impact of physical, visual and intellectual impairment on performing specific swimming tasks. Stroke rate is more stable all through the sport classes than both swimming speed and stroke length. Most physically disabled swimmers adopt the catch-up coordination model. Stroke rate is responsible for most of the intracycle velocity variation in swimmers with amputations or malformations of the upper limbs. No study was found on propulsive efficiency. Swimmers with disabilities should work more on stroke rate, with small decreases in stroke length to achieve higher swimming speeds, lower swim coordination index (more negative) and lower speed variations.

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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.

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O objetivo deste estudo foi verificar as respostas da frequência média de ciclos de braçadas (FB) e da distância média percorrida por ciclo de braçada (DC) no nado crawl ao longo de série de natação na intensidade de 95% da velocidade média dos 400 m (V400), até a exaustão. Onze nadadores realizaram 400 m em máxima intensidade para determinação da V400, e, posteriormente, uma série a 95% da V400 (95v) com média de 2,88 ± 1,37 repetições de 400 m e intervalos de 40 s de repouso passivo, quarenta e oito horas após a V400. A duração da série a 95% da V400 foi normalizada a 100%, de modo individual, e posteriormente, foi dividida em cinco momentos (0, 25, 50, 75 e 100%) para a análise de FB e DC, que foram comparadas ao longo da série. Resultados: houve manutenção dos parâmetros cinemáticos apenas entre os momentos 0 e 25%. Ocorreram aumento da FB e diminuição da DC nos últimos momentos (75 e 100%) em comparação aos demais momentos da série 95v. Ao nadar nesta intensidade, que está situada o domínio de intensidade severa, nadadores não são capazes de manter a técnica constante ao longo da duração total da série...(AU)

The objective of this study was to investigate the stroke rate (SR) and the stroke length (SL) responses in front crawl along swimming training series in the intensity of 95% of the average velocity of 400 m (V400) until exhaustion. Eleven swimmers performed 400 m at maximum intensity for determining V400, and subsequently, a series of 95% the V400 (95v) with average 2.88 ± 1.37 trials of 400 m and intervals of 40 s of passive rest, 48 hours after the V400. The duration of the 95V was normalized to 100%, individually, and, later, it was divided into five moments (0, 25, 50, 75, and 100%) for the SR and SL analysis, which were compared over the series. Results: there was maintenance of kinematic parameters only between moments 0 and 25%, The SR increased and the SL decreased in the end of the series (75 and 100%) compared to other moments. When swimming at this intensity, which is situated in severe intensity domain, swimmers are not able to keep constant the technique over the entire duration of the series...(AU)

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O estudo objetivou verificar a correlação da força isométrica de extensão de joelho e quadris com o desempenho na virada do nado livre. Participaram do estudo 9 nadadores com experiência em competições de natação (idades: 23,11 ± 4,20 anos; estatura: 178 ± 0,05 cm; massa: 77,73 ± 8,56 kg; IMC: 24,46 ± 2,40 kg/m²). Um transdutor de força acoplado ao aparelho leg press horizontal foi usado para determinar a contração voluntária máxima e a taxa de desenvolvimento de força pico em três diferentes ângulos de joelho (78,4 ± 5,9o ; 100,4 ± 5,3o ; 116,2 ± 8,8o ) durante extensão máxima de joelhos e quadris. O desempenho da virada do nado livre foi registrado por videogametria subaquática e analisado por meio do software Kinovea 08.15. Cada nadador realizou três viradas máximas sendo registrado o melhor tempo entre as tentativas. Foram utilizadas média e desvio padrão, ANOVA one-way, correlação de Pearson e α= 0,05. Os resultados indicaram que os maiores ângulos registraram maiores picos de contração voluntária máxima: 2279,14 ± 441,89 N; 4690,98 ± 1148,06 N; 5052,57 ± 1349,92 N e taxa de desenvolvimento de força pico: 18068,33 ± 3238,18 N/s; 24790,11 ± 7214,60 N/s; 25684,88 ± 9366,64 N/s. A correlação foi significativa (r = - 0,74) entre o desempenho da virada do nado livre (1,80 ± 0,14s) e a contração voluntária máxima no maior ângulo. Logo, a capacidade de membros inferiores em produzir força máxima, em ângulos de extensão de joelhos e quadris próximos a 116°, pode ter importante papel no desempenho da virada. Além do mais, essa avaliação pode ser uma ferramenta na avaliação e prescrição de treinamento de viradas...(AU)

The study aimed to assess the correlation between isometric strength of knee and hip extension and the performance at freestyle flip turn. Participated in the study 9 swimmers with experience in swim championships (age: 23.11 ± 4.20 years, height: 178 ± 0.05 cm, weight: 77.73 ± 8.56 kg, BMI: 24.46 ± 2.40 kg/m²) comprised the sample. A transducer unit coupled to the horizontal leg press was used to determine the maximum voluntary contraction and rate of strength development peak at three different angles of knee (78.4 ± 5,9o ; 100.4 ± 5.3o ; 116.2 ± 8.8o ) during maximal knee extension and hip. The freestyle flip turn performance was recorded by an underwater camera and subsequently analyzed by Kinovea 08.15 software. Each swimmer performed three maximal attempts and recorded the best time. Mean, standard deviation, one-way ANOVA, Pearson's correlation and α = 0.05 were used. The results indicated a larger angles recorded highest peaks of maximum voluntary contraction: 2279.14 ± 441.89 N; 4690.98 ± 1148.06 N; 5052.57 ± 1349.92 N and peak rate force development:18068.33 ± 3238.18 N/s, 24790.11 ± 7214.60 N/s, 25684.88 ± 9366.64 N/s. The correlation was significant (r = - 0.74) between the performance at freestyle flip turn (1.80 ± 0,14s) and the maximum voluntary contraction in wider angle. Thus, the ability of the lower limbs to produce maximum force in angles of knee extension and hip near 116°, may play a role in performance at freestyle flip turn. Furthermore, this assessment can be a tool in the evaluation and training of the turning....(AU)

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