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- Effect of glide on neuromuscular adaptation in breaststroke swimming: a case study of an elite swimmerPublication . Conceição, Ana; Frédéric, Puel; Louro, Hugo; Morgado, Sónia; Seifert, LudovicThe aim of this case study was to examine the upper and lower limbs muscular responses of one elite breaststroke swimmer at three different glide and speed conditions, to understand how strength and condition could be optimized during training. Surface electromyograms (sEMG) were collected in biceps brachii (BB), biceps femoris (BF), deltoid anterior (DA), gastrocnemius medialis (GM), pectoralis major (PM) rectus femoris (RF), tibialis anterior (TA), and tríceps brachii (TB) during 18 x 25 m breaststroke trials performed at three different glide( normal, maximal, minimal) and speed (70, 80 and 90% of maximal speed) conditions. Each trial required an individually imposed swimming speed corresponding to 70, 80 and 90% of the swimmer maximal speed and a specific glide condition: minimal glide, normal glide and maximal glide. In maximal glide, higher participation of TB and DA and TA, RF, and GM muscles. In normal glide, a significant higher participation of all the muscles occurred, except for GM. In minimal glide, a significant higher participation of all the muscles occurred, except for the PM. We have also found that swimming at 90% of maximal speed led to significant higher use of the BB and PM muscles, for the upper limbs and BF and TA muscles for the lower limbs. In conclusion, the swimmer recruited different muscles as increasing his swimming speed and when gliding differently than normally. It suggested that strength and condition should be trained for various swimming speeds associated to various conditions of glide to ensure behavioral adaptability in competition.
- Análise da qualidade do sistema de observação do comportamento técnico de bruçosPublication . Matos, Telmo; Silva, António; Conceição, Ana; Freitas, João; Campaniço, Jorge; Louro, HugoO presente estudo teve como objetivo o processo de construção e validação de um instrumento de observação. Neste contexto, centrámos a análise num requisito fundamental – a validade e fiabilidade do instrumento, instrumento este que servirá de base ao registo dos comportamentos observados durante a execução de vinte ciclos gestuais na técnica de bruços. O instrumento foi composto por um sistema de Formatos de Campo (Oliveira, Campaniço & Anguera, 2001), com base em referências da metodologia observacional e modelos biomecânicos da Natação (Colman & Persyn, 1993; Silva & Alves, 2000; Louro, Garrido, Ferraz, Marinho, Conceição, Tolentino, Barbosa & Silva, 2009), dando especial evidência a cinco critérios taxionómicos que agregam, na forma de códigos alfa-numéricos, a informação decisiva para descrever comportamentos que definem a técnica de bruços. Para garantir o rigor e objectividade do instrumento, foi efectuada a análise à qualidade e validade do instrumento recorrendo ao Índice de Kappa (Anguera, 1993; Blanco 1993, 1997), com base nos registos de cinco observadores treinados (inter-observadores, 96.9%) e, para efeitos de precisão, de mais um perito (intra-observador, 97.8%). Como conclusão, é possível apurar que a valência deste instrumento qualitativo é bem evidente pelos elevados valores de concordância, tornando-se um instrumento adequado para observar os comportamentos técnicos dos nadadores em bruços. - The aim of this study was the process of construction and validation of an observation instrument. In this context, we focused the analysis on a fundamental requirement - the validity and reliability of the instrument. This instrument will serve as basis for the registration of behaviors observed during the execution of twenty gestural cycles of the breaststroke technique. The instrument consisted of a Field Formats system (Oliveira, Campaniço & Anguera, 2001), based on references of the observational methodology and Swimming biomechanical models (Persyn & Colman, 1993; Silva & Alves, 2000; Louro, Garrido, Ferraz, Marinho, Conceição, Tolentino, Barbosa & Silva, 2009), giving special emphasis to five taxonomic criteria that aggregate, in the form of alpha-numeric codes, crucial information to describe behaviors that define the breaststroke technique. To ensure the instrument’s accuracy and objectivity, an analysis of the instrument’s quality and validity was made, using the Kappa Index (Anguera, 1993; Blanco 1993, 1997). This analysis was based on records of five trained observers (inter-observer, 96.9%) and, for accuracy purposes, another expert (intraobserver, 97.8%). In conclusion, it is possible to determine that, given the high reliability values, the validity of this qualitative instrument is evident, making it a suitable instrument to observe the technical behavior in breaststroke swimmers.
- Neuromuscular Fatigue during 200 M BreaststrokePublication . Conceição, Ana; Silva, António; Barbosa, Tiago; Karsai, Istvan; Louro, HugoThe aims of this study were: i) to analyze activation patterns of four upper limb muscles (duration of the active and non-active phase) in each lap of 200m breaststroke, ii) quantify neuromuscular fatigue, with kinematics and physiologic assessment. Surface electromyogram was collected for the biceps brachii, deltoid anterior, pectoralis major and triceps brachii of nine male swimmers performing a maximal 200m breaststroke trial. Swimming speed, SL, SR, SI decreased from the 1st to the 3rd lap. SR increased on the 4th lap (35.91 ± 2.99 stroke·min-1). Peak blood lactate was 13.02 ± 1.72 mmol·l-1 three minutes after the maximal trial. The EMG average rectified value (ARV) increased at the end of the race for all selected muscles, but the deltoid anterior and pectoralis major in the 1st lap and for biceps brachii, deltoid anterior and triceps brachii in the 4th lap. The mean frequency of the power spectral density (MNF) decreased at the 4th lap for all muscles. These findings suggest the occurrence of fatigue at the beginning of the 2nd lap in the 200m breaststroke trial, characterized by changes in kinematic parameters and selective changes in upper limb muscle action. There was a trend towards a non-linear fatigue state.
- Intra- and inter-individual variability in the underwater pull-out technique in 200 m breaststroke turnsPublication . Gonjo, Tomohiro; Olstad, Bjørn; Stastny, Jan; Conceição, Ana; Seifert, LudovicThe purpose of the present study was to investigate the intra- and inter-individual variability in arm-leg coordination during the underwater phase of the turn segment in 200 m breaststroke. Thirteen male swimmers were recruited and performed a 200 m breaststroke in a pre-calibrated 25 m pool. Sub-phases during the underwater segment were obtained using a notational analysis, and the mean velocity, displacement and duration during each sub-phase were obtained. A hierarchical cluster analysis (HCA) was performed using the analyzed variables in all phases to identify inter-individual variability and random intra-individual variability. In addition, a linear mixed model (LMM: lap as a fixed effect and the participant as a random effect) was conducted to investigate systematic intra-individual variability. HCA identified three coordination patterns that were distinguished by the timing of the dolphin kick relative to the arm pull-out and the duration of the glide with arms at the side. All swimmers except one performed the arm pull-out after the dolphin kick. Nine swimmers maintained one coordination pattern, but other swimmers switched their coordination during the trial, particularly by shortening the duration of the glide with arms at the side. LMM showed a linear decrease (from the first to the last turn) in the time gap between the end of the dolphin kick and the start of the arm pull-out (a glide with the streamlined body position; F = 9.64, p = 0.034) and the glide duration with the arms at the side (F = 11.66, p = 0.015). In conclusion, both inter- and intra-individual variabilities during the underwater phase were evident in 200 m breaststroke turns, which were categorized into three patterns based on the timing of the dolphin kick and the duration of glides.
- Stability of behaviour patterns in the 200m breaststrokePublication . Louro, Hugo; Silva, António; Campaniço, Jorge; Matos, Telmo; Conceição, AnaThe aim of this study was to analyse the stability of the breaststroke technique in five elite swimmers in a 200m event using a qualitative analysis. The codification of the behaviour of each swimmer during the execution of 20 cycles was achieved using an ad hoc observational instrument comprised of a system of categories and field formats to detect the behavioural patterns (T-patterns); software was used for identifying the technical behaviour of stable structures. The results showed that the stability behaviour varied depending on the swimmer, as the variations of codes in each round produced distinct configurations to determine the differences between cycles for the same swimmer. It was concluded that the instrument used in this study plays an important role through the existence of stable behaviour in the breaststroke technique. It was also concluded that there are distinct patterns and behaviours between swimmers during each lap of the race.
- Occlusion technique in swimming: a training method to improve exchange block time in swimming relaysPublication . Conceição, Ana; Costa, Aldo M; Silva, António J; Sobreiro, Pedro; Louro, HugoSwimming relay events have the concern regarding a good start is shared between the incoming and outgoing swimmers. The aim of this study was to evaluate changes in exchange block time (eBT) for swimming relay events as a result of a four-week training program using the occlusion technique. MeThodS: Twenty-eight national swimmers, 12 males (age: 17±1.83 years) and 16 females (age: 19.94±5.65 years) participated in this study. Subjects were required to undergo a training program on visual perception in relay swimming over the course of four weeks; they watched videos corresponding to the last movements of a swimmer during a 4×100m freestyle relay event. The videos were presented with temporal occlusion corresponding to predetermined approaching distances (7.5 m, 5.0 m, and 2.5 m). Swimmers were required to simulate a typical position for exiting the block and to estimate the time-to-contact of the incoming swimmer. The eBT was collected during a real 4×100-m freestyle competition before and after the application of the training program. RESULTS: Female swimmers showed a decreased in EBT, with an improvement of 1.42%, despite there not being a signifcant difference (p=0.68). The male swimmers had a higher improvement in eBT after the training, with a decrease of 13.34% (p=0.68). coNcluSioNS: Visual perception practice using video occlusion techniques seems to have a positive effect. on eBT in swimming relay events, particularly in female swimmers
- Strategy operationalization in a Taekwondo FederationPublication . Sobreiro, Pedro; Sousa, José; Louro, Hugo; Conceição, Ana
- Análise da percepção visual nas rendições em natação pura desportivaPublication . Fonseca, Andreia; Louro, Hugo; Conceição, AnaNo âmbito das estafetas em NPD existe uma escassez de investigação sobre as rendições. Um dos desafios é minimizar o tempo de saída do atleta do bloco com o outro que toca na parede, focamo-nos assim no estudo das habilidades visuais nas rendições, verificando a ação motora através da aplicação de um programa de treino de perceção visual nas rendições. O objetivo é verificarmos em que medida é que através da utilização de um programa de treino, a técnica da rendição nas estafetas traz melhorias no tempo de reação. A amostra foi composta por 28 Rev UIIPS. 2019; 7(2): 181-193 182 nadadores com idade 16.36±4.49 anos. Nos resultados sobre a diferença de tempos, as nadadoras em comparação com os nadadores apresentaram melhorias para cada distância de oclusão e sobre a diferença do tempo de reação, as nadadoras apresentaram um efeito positivo no TR após, no entanto os nadadores apresentaram melhorias maiores no TR após a competição.
- Neuromuscular and motor patterns in breaststroke techniquePublication . Conceição, Ana; Silva, António; Barbosa, Tiago; Campaniço, Jorge; Louro, HugoAbstract – Te aim of this study was to analyze the inter-temporal neuromuscular and motor patterns in breaststroke technique. Five national level male swimmers performed 200 m breaststroke at maximal effort. Electromyography data onbiceps brachii, deltoid anterior, pectoralis major and triceps brachiiwere analysed. Te relative duration of active and non-active phase and the average rectifed value for the neuromuscular patterns were recorded. Te swim bouts were videotaped in sagittal plane with a pair of cameras and the Teme software 5.0 was used toanalyse the detected patterns in each swimmer. Te neuromuscular pattern revealed that by the average rectifed value the biceps brachiiand triceps brachiiwere increased at the end of the test for swimmers 1 and 5, while biceps brachii, deltoid anteriorand pectoralis majorwere increased for swimmers 2 and 4. Different motor patterns between cycles, and between swimmers were observed.We found similarities between the swimmers, adjusting their style to the technical model. Te absence of a neuromuscular pattern for all swimmers could be related to different technical models used by each swimmer, as presented in the motor patterns. Tese fndings suggested that each swimmers adapted their own motor and neuromuscular pattern in a unique and distinct way
- The effect of handlebar height and bicycle frame length on muscular activity during cycling: a pilot studyPublication . Conceição, Ana; Milheiro, A.; Parraca, J.; Rocha, F.; Espada, M.; Santos, F.; Louro, HugoThe cycling literature is filled with reports of electromyography (EMG) analyses for a better understanding of muscle function during cycling. This research is not just limited to performance, as the cyclist’s goal may be rehabilitation, recreation, or competition, so a bicycle that meets the rider’s needs is essential for a more efficient muscular activity. Therefore, the purpose of this study was to understand the contribution of the activity of each of the following muscles: TD (trapezius descending), LD (latissimus dorsi), GM (gluteus maximus), and AD (anterior deltoid) in response to different bicycle-rider systems (handlebar height; bicycle frame length) and intensities in a bicycle equipped with a potentiometer. Surface EMG signals from muscles on the right side of the body were measured. A general linear model test was used to analyze the differences between muscle activation in the test conditions. Effect sizes were calculated using a partial Eta2 (η 2 ). The level of significance was set at 0.05. Muscle activation of different muscles differs, depending on the cycling condition (Pillai’s trace = 2.487; F (36.69) = 9.300; p < 0.001. η 2 = 0.958), mostly during low intensities. In high intensities, one specific pattern emerges, with a greater contribution of GM and TD and weaker participation of LD and AD, enhancing the cycling power output.