This study aimed to determine whether: i) tethe-red-swimming can be used to identify the asymmetry during front crawl swimming style; ii) swimmers that perform unilateral breathing present greater asymmetry in comparison to others that use bilateral breathing; iii) swimmers of best performance present smaller asymmetry than their counterparts; iv) repeated front crawl swimming movements influence body asymmetry. 18 swimmers were assessed for propulsive force parameters (peak force, mean force, impulse and rate of force development) during a maximal front crawl tethered-swimming test lasting 2 min. A factorial analysis showed that propulsive forces decreased at the beginning, intermediate and end of the test (p<0.05), but the asymmetries were not changed at different instants of the test. When breathing preference (uni- or bilateral) was analyzed, asymmetry remained unchanged in all force parameters (p>0.05). When performance was considered (below or above mean group time), a larger asymmetry was found in the sub-group of lower performance in comparison to those of best performance (p<0.05). Therefore, the asymmetries of the propulsive forces can be detected using tethered-swimming. The propulsive forces decreased during the test but asymmetries did not change under testing conditions. Although breathing preference did not influence asymmetry, swimmers with best performance were less asymmetric than their counterparts.

Background: Changes in the proprioceptive system are associated with aging. Proprioception is important to maintaining and/or recovering balance and to reducing the risk of falls. Objective: To compare the performance of young and active elderly adults in three proprioceptive tests. Method: Twenty-one active elderly participants (66.9±5.5 years) and 21 healthy young participants (24.6±3.9 years) were evaluated in the following tests: perception of position of the ankle and hip joints, perceived force level of the ankle joint, and two-point discrimination of the sole of the foot. Results: No differences (p>0.05) were found between groups for the joint position and perceived force level. On the other hand, the elderly participants showed lower sensitivity in the two-point discrimination (higher threshold) when compared to the young participants (p < 0.01). Conclusion: Except for the cutaneous plantar sensitivity, the active elderly participants had maintained proprioception. Their physical activity status may explain similarities between groups for the joint position sense and perceived force level, however it may not be sufficient to prevent sensory degeneration with aging.

The aim of this study was to determine changes in swimming parameters, stroke coordination and symmetry after repeated high intensity swimming efforts in swimmers of different performance levels and para-swimmers. Method: Forty swimmers (20 ablebodied, allocated to higher and lower performance groups-G1 and G2, respectivelyand 20 impaired swimmers -S5 to S10) were recorded by 4 underwater cameras while performing repeated 50m maximum front-crawl swimming with a ten-second interval for each time endured by the swimmer. A cycle stroke was digitized using SIMI Reality Motion Systems in the first and last trials to analyze the kinematic parameters. The comparison among groups and conditions was performed by Mixed ANOVA Models with p<0.05. Results: For all groups, swimming velocity, stroke rate and stroke index showed reduction over time, while stroke length and intracyclic velocity variation did not show significant changes. Conclusions: Training to maintain stroke rate is necessary to support performance since it is the main cause of velocity decrease. Stroke dimensions and individual underwater phases were not sufficient to distinguish groups or conditions.Hand velocity decreased probably due to a decline in energy capacity, propulsive force and passive drag caused by the fatigue process.

ResumoAo contrário do que ocorre em provas de piscina, competições em águas abertas estão sujeitas as condições ambientais, sendo uma delas as baixas temperaturas. Em determinadas circunstâncias é permitido o uso de roupas especiais para evitar hipotermia. O objetivo do estudo foi verifi car os efeitos do uso da roupa de neoprene em um grupo composto por triatletas e nadadores, comparado ao uso de vestimentas convencionais (sunga) sobre variáveis cinemáticas e psicofi siológicas do nado. Participaram 20 homens (12 triatletas e oito nadadores) de idade 22,0 ± 6,6 anos com desempenhos que correspondem a 75 ± 7,7% do melhor tempo brasileiro na prova de 400 m. Os atletas realizaram duas repetições máximas e duas submáximas de 400 m em nado "crawl", com e sem o uso da roupa de neoprene. Foram comparadas a velocidade média (VM), comprimento de braçada (CB), frequência de braçada (FB), índice de nado (IN), percepção subjetiva de esforço (PSE), frequência cardíaca (FC), e concentração de lactato sanguíneo (LAC). Um conjunto de ANOVAs com medidas repetidas do tipo "two-way" foi aplicado. Quando diferenças foram encontradas o teste de Tukey foi empregado. Com o traje de neoprene, em máxima intensidade, o tempo para nadar a distância foi 6,4% menor, com manutenção da FB e aumento da CB, as variáveis psicofi siológicas não diferiram estatisticamente. Em esforço submáximo, o uso do traje de neoprene resultou em menor FB, maior CB, maior IN e em menores valores de FC, LAC e PSE (p < 0,05). O uso do traje proporcionou melhoria do desempenho nos aspectos biomecânicos, fi siológicos e perceptivos e que o aumento da VM em esforço máximo não depende exclusivamente de alterações na FB e CB. Possivelmente, incrementos nos parâmetros associados ao nado pode ter melhorado a efi ciência mecânica do movimento, a qual pode ter provido uma economia de movimento que resultou em melhor desempenho. UNITERMOS: Traje especial; Natação; Desempenho.As provas de natação realizadas em águas abertas tiveram sua popularidade aumentada a partir da inclusão do triatlo e das maratonas aquáticas no programa de provas dos Jogos Olímpicos. Ao contrário do que ocorre em provas de piscina, nas provas em águas abertas os competidores estão sujeitos a diferentes condições ambientais que envolvem correntes, turbulência e principalmente baixas temperaturas da água. Para minimizar os efeitos das baixas temperaturas os competidores têm utilizado roupas especiais de neoprene. Para a categoria de elite, o traje de neoprene é permitido em temperaturas abaixo de 20 ºC (CONFEDERAÇÃO BRASILEIRA DE TRIATHLON, 2010). O traje de neoprene começou a ser utilizado a partir do exemplo dos surfi stas e mergulhadores que desejavam minimizar os problemas térmicos de perda de calor corporal -o risco de hipotermia (DE LUCAS,

Santos, KB, Bento, PCB, Pereira, G, and Rodacki, ALF. The relationship between propulsive force in tethered swimming and 200-m front crawl performance. J Strength Cond Res 30(9): 2500-2507, 2016-The aims of this study were to determine whether propulsive force (peak force, mean force, impulse, and rate of force development) and stroke rate change during 2 minutes of front crawl tethered swimming and to correlate them with the stroke rate and swimming velocity in 200-m front crawl swimming. Twenty-one swimmers (21.6 ± 4.8 years, 1.78 ± 0.06 m, 71.7 ± 8.1 kg), with 200-m front crawl swimming performance equivalent to 78% of the world record (140.4 ± 10.1 seconds), were assessed during 2 minutes of maximal front crawl tethered swimming (propulsive forces and stroke rate) and 200-m front crawl swimming (stroke rate and clean velocity). Propulsive forces decreased between the beginning and the middle instants (∼20%; p ≤ 0.05) but remained stable between the middle and the end instants (∼6%; p > 0.05). The peak force was positively correlated with the clean velocity in the 200-m front crawl swimming (mean r = 0.61; p< 0.02). The stroke rates of the tethered swimming and 200-m front crawl swimming were positively correlated (r = 45; p≤ 0.01) at the middle instant. Therefore, the propulsive force and stroke rate changed throughout the 2 minutes of tethered swimming, and the peak force is the best propulsive force variable tested that correlated with 200-m front crawl swimming performance.

The aging is accompanied by a gradual decline in balance and increases risk of falls. Pilates has been used for balance training. e purpose of this research was to systematize studies regarding the effects of Pilates exercise interventions on static and dynamic balance of elderly people. A survey was conducted in three indexed databases: Medline/Pubmed, Scopus and Science Direct, using the descriptors “balance” or “equilibrium” with the term “Pilates”. Fifteen articles were selected and used in this systematic review. Based on the results, we observed that the practice of Pilates with a minimum frequency of two sessions per week for an hour lasting for a period of at least five weeks or three times per week for 12 sessions or more showed improvement on static and dynamic balance of elderly.

Although swimming is recognized as a symmetrical sport, equivalence between each body side cannot be insured. Swimmers with physical and motor impairment may present asymmetries that are even more pronounced. Therefore, the objective of this study was to assess the symmetry of temporal coordination in the front crawl stroke phases and their dimensional characteristics among swimmers of different levels of skill and disabled swimmers. Forty-one swimmers (28 men and 13 women, 18,8 ± 3,3 years, divided 21 of them into groups of high and low level of skill and 20 in disabled swimmers group) performed a 50m maximum of front-crawl test while they were recorded by six synchronized cameras (four underwater and two above water) for analysis of the stroke phases, stroke dimensions (anteroposterior, mediolateral and vertical amplitude), index of coordination and hand speed. The symmetry index was calculated by the difference between the right and the left strokes. Comparisons were made using the Kruskal-Wallis test and multivariate comparisons were made using the Mann-Whitney test, with p <0.05. Asymmetry was noted in anteroposterior and mediolateral amplitudes of the stroke, index of coordination, duration of the recovery phase, each of the underwater phases and in the hand speed during the downseep phase, regardless of the level of skill or impairment. The disabled swimmers also showed asymmetry in the vertical amplitude of the stroke as well as in the insweep and upsweep speed. The reasons for these asymmetries may be the preference for unilateral breathing, force imbalance between pairs of homologous muscles and motor control deficit. The training with stereotypic movements may explain the similarity of asymmetries among the different groups of swimmers. OPEN ACCESSCitation: Santos KB, Bento PCB, Payton C, Rodacki ALF (2020) Symmetry in the front crawl stroke of different skill level of able-bodied and disabled swimmers. PLoS ONE 15(3): e0229918. https://

Purpose. Intracyclic velocity variation is an important kinematic parameter to evaluate swimming performance. It can be estimated by a fixed point at the swimmer’s hip. The aim of the study was to determine the reproducibility and repeatability of active light markers to measure intracyclic velocity variation in swimming. Methods. Reproducibility and repeatability were tested by image measurement, by five manual digitizing processes and five sessions of automatic tracking of a LED marker set in a swimmer’s hip. The procedures were evaluated by the intraclass correlation coefficient, and the agreement between the methods was evaluated with Bland-Altman plots. The reproducibility was excellent in both procedures. Results. The repeatability of manual digitalization ranged between satisfactory to excellent, while the repeatability of automatic tracking was excellent. In addition, the Bland-Altman plots displayed a good agreement between manual and automatic measurements. The automatic tracking was 27% faster than manual digitization. Conclusions. Active markers are promising to evaluate the intracyclic velocity variation of swimmers, with a faster response than the common manual processing.