The effects of fatigability on shooting skill performance in goalball penalty shots

This study evaluated the influence of acute fatigue on shooting skill performance in goalball penalty shots. Eleven sub-elite male players were evaluated in an official court using a two-dimensional procedure (60 Hz) to compute the mean radial error, bivariate variable error and accuracy, and three-dimensional kinematics (240 Hz) to measure ball velocity. Rating of perceived exertion, blood lactate concentration and knee extension isometric maximal voluntary contractions were assessed at rest and immediately after the completion of an incremental test specific to goalball. Although significant differences were observed for rating of perceived exertion (pre: M = .36 AU, SD = .67; post: M = 9.27 AU, SD = .79), blood lactate concentration (M = 1.33 mM, SD = .51; M = 9.04 mM, SD = 2.25) and peak force (M = 597.85 N, SD = 132.35; M = 513.37 N, SD =107.00) at the end of the incremental test, no differences were identified in the pre and post moments for mean radial error (M = .10 m, SD = 1.01; M =.37 m, SD = 2.19), bivariate variable error (M = 3.56 m, SD = .70; M = 3.25 m, SD = .70), accuracy (M = 3.68 m, SD = .74; M = 3.78 m, SD = 1.13) and ball velocity (M = 18.53 m.s-1, SD = 1.53; M =18.46 m.s-1, SD = 1.65). We concluded that even though significant levels of fatigability can be attributed to the incremental test specific to goalball, shooting skill performance in goalball penalty shots does not appear to be affected. However, further investigations are needed so that goalball coaches can develop strategies that contribute to improve performance in this technical action. Such improvements are decisive for the outcome of a match

Proposal of a Conditioning Activity Model on Sprint Swimming Performance

This study aimed to propose a conditioning activity (CA) model to stimulate improvement on neuromuscular responses, mechanical parameters and for the 50-m freestyle swimming. Thirteen male swimmers (19 ± 3 years and performances of 77% in relation to World Championship records) performed four CA protocols followed by a maximum performance in the 50-m freestyle. In the first protocol (P1) swimmers performed a standard warm-up (∼15 min); in the second protocol (P2) lunges (3 × 85% of the one-repetition maximum); in the third (P3) pull-ups (3 maximum repetitions) and box jumps 40 cm high and 60 cm deep (1 × 5 with 10% of the corporal weight); and in the fourth protocol (P4) a combination of exercises from the second and third protocols. CA protocols had no effect on the standard warm-up. However, P2 performance (27.01 ± 1.25 s) was similar to P1 (27.01 ± 1.18 s) and presented higher positive effects in mechanical parameters for the swim start performance in comparison to other protocols, contributing to improvements in the 50-m freestyle. In addition, turnaround time also had a negative effect, mainly in P3 (3.12 ± 0.28 s), signaling the improvement of this variable in all protocols (P1: 3.30 ± 0.38 s; P2: 3.17 ± 0.30 s; P4: 3.17 ± 0.34 s). P2 (after: 80 ± 11%; before: 82.7 ± 9.9%) and P3 (after: 82.7 ± 9.9%; before: 85.1 ± 9.7%) presented a possible positive effect on the percentage of voluntary activation in relation to P1 (after: 79.3 ± 10.7%; before: 76.3 ± 12%). In conclusion, the proposed conditioning activity protocols were not efficient for performance improvement in the 50-m freestyle compared to the standard model and seem to specifically influence each phase of the event

Proposition of a hybrid model of postactivation potentiation to improve the performance of sprinter swimmers

Tradicionalmente na natação, os protocolos de aquecimento são aplicados em elevado volume e intensidade moderada. Entretanto, evidências demonstram que a utilização de esforços com elevada intensidade, principalmente exercícios que envolvem o desenvolvimento de força, podem trazer algum benefício ao nadador, efeito reconhecido como potencialização pós-ativação (PPA). Com isso, o objetivo do presente estudo foi propor um modelo híbrido para a PPA a fim de melhorar o desempenho na natação e verificar as respostas neuromusculares e parâmetros mecânicos em relação à PPA. Para isso, 13 nadadores realizaram quatro protocolos de PPA seguidos por um desempenho máximo de 50m. No primeiro protocolo (P1) os participantes realizaram um aquecimento convencional. No segundo protocolo (P2), os nadadores foram submetidos a exercício de \"afundo\", no terceiro (P3) realizaram esforços na barra fixa e saltos sobre o caixote e no quarto protocolo (P4), os nadadores foram submetidos ao protocolo híbrido, constituído pelos exercícios tanto do segundo como do terceiro protocolo. Os protocolos de PPA não apresentaram efeito sobre o aquecimento convencional. Porém, o P2 (27,01 ± 1,25 s) foi o que manteve o mesmo desempenho do P1 (27,01 ± 1,18 s) e apresentou melhoras nos parâmetros mecânicos da saída do bloco em relação aos outros protocolos. Ainda, o tempo de virada também apresentou efeito positivo, principalmente no P3 (3,12 ± 0,28 s) o que sinaliza a melhora dessa variável em todos os protocolos. Os valores de força pico (300,95 ± 53,11 N) e força média (258,04 ± 51,89 N) para os membros superiores apresentaram uma possível chance positiva de aumento somente no intervalo individual do P4 e para membros inferiores todos os protocolos apresentaram um possível efeito positivo na porcentagem de ativação voluntária em relação ao aquecimento convencional. Pode-se concluir que os protocolos propostos não foram eficientes para melhora do desempenho nos 50m nado crawl em relação ao modelo convencional.Traditionally in swimming the warm-up protocols are applying in a high volume and moderate intensity. However, evidences show that the utilization of efforts with high intensity, mainly with trainings that involves the force development, can bring some benefit to the swimmer, effect known as post-activation potentiation (PAP). Thereby, the objective of the present study was to propose a hybrid model for PAP in order to improves swimming performance and verify neuromuscular responses and mechanical parameters in relation to PAP. For this, 13 swimmers performed four PAP protocols followed by a maximum performance of 50m. In the first protocol (P1) the participants performed a conventional warm-up. In the second protocol (P2) the swimmers of submitted to lunge exercise, in the third (P3) they made efforts in the pull-up and box jumps on the and, in the fourth protocol (P4), the swimmers were submitted to the hybrid model, using the second and the third protocol exercises. The PAP protocols had no effect on standard warm-up. However, the P2 (27,01 ± 1,25 s) was the one that maintained the same performance of P1 (27,01 ± 1,18 s) and presented improvements in the mechanical parameters of the block exit in relation to the other protocols. Still, the turn time also had a positive effect, mainly in P3 (3,12 ± 0,28 s) which shows the improvement of this variable in all protocols. The values of peak strength (258,04 ± 51,89 N) for the upper limbs showed a possible positive chance of increase only in the individual P4 interval and for all lower limbs of voluntary activation in relation to standard warming up. In conclusion, the proposed protocols were not efficient for performance improvement at 50-m free swim compared to the standard model

Confiabilidade de um circuito multimodal incremental na determinação do limiar anaeróbio de idosos por meio da dosagem do lactato sanguíneo

O estudo teve por objetivo medir a confiabilidade de um circuito multimodal incremental na determinação do limiar anaeróbio (LAN) de idosos por meio da dosagem do lactato sanguíneo (LS). A amostra foi composta por 20 idosos com idade igual a 66,8 anos, não sedentários, do sexo feminino (75%). O circuito foi composto por quatro exercícios, em um protocolo de três fases, com intervalos de 72 horas entre as fases. A primeira fase consistiu na aprendizagem dos exercícios e marcação do metrônomo e teve duração de duas semanas. As fases 2 e 3 foram constituídas por teste e reteste, constituídos de quatro exercícios: meio agachamento com flexão e extensão de cotovelo; caminhada; sentar e levantar da cadeira; subir e descer do step. Ao final de cada estágio foram realizadas as coletas de LS e obtidos os valores para a Percepção Subjetiva de Esforço. Determinou-se o limiar anaeróbio 2 (LAN 2) com utilização do modelo Bi-segmentado e do modelo matemático Distância Máxima. Para a análise de confiabilidade intraobservador e de concordância, foram utilizados o Coeficiente de Correlação Intraclasse (CCI) e o teste de concordância Bland-Altman. Para análise da igualdade de médias no teste e no reteste foram utilizados os testes One-way ANOVA e os testes de Wilcoxon ou Friedman. Os resultados indicaram confiabilidade e concordância entre as medidas teste-reteste para as variáveis estudadas, sugerindo a adequação do circuito multimodal incremental na determinação do limiar anaeróbio de idosos por meio da dosagem do lactato sanguíneo.The study aimed to measure the reliability of an incremental multimodal circuit in determining the anaerobic threshold (AT) in the elderly through the measurement of blood lactate (BL). The sample consisted of 20 elderly people aged 66.8 years, non-sedentary, female (75%). The circuit was composed by four exercises, in a three-phase protocol, with 72-hour intervals between phases. The first phase consisted of learning the exercises and marking the metronome and lasted for two weeks. Phases 2 and 3 consisted of test and retest with four exercises: half squat with flexion and elbow extension; walking; sit and get up from the chair; up and down the step. At the end of each phase, BL collections were performed and the values for the Subjective Effort Perception were obtained. The anaerobic threshold 2 (AT 2) was determined using the Bi-segmented model and the Maximum Distance mathematical model. For the analysis of intraobserver reliability and concordance, the Intraclass Correlation Coefficient (ICC) and the Bland-Altman concordance test were used. One-way ANOVA and Wilcoxon or Friedman tests were used to analyze the equality of means in the test and in the retest. The results indicated reliability and agreement between the test-retest measures for the studied variables, suggesting the adequacy of the incremental multimodal circuit in determining the anaerobic threshold in the elderly through the measurement of blood lactate