How Should the Transition from Underwater to Surface Swimming Be Performed by Competitive Swimmers?

Despite the increasing importance of the underwater segment of start and turns in competition and its positive influence on the subsequent surface swimming, there is no evidence on how the transition from underwater to surface swimming should be performed. Therefore, the aim of the present study was to examine the role of segmental, kinematic and coordinative parameters on the swimming velocity during the pre-transition and transition phases. A total of 30 national male swimmers performed 4 × 25 m (one each stroke) from a push start at maximum velocity while recorded from a lateral view by two sequential cameras (50 Hz), and their kinematic and coordinative swimming parameters were calculated by means of two-dimensional direct linear transformation (DLT) algorithms. Unlike pre-transition, backward regression analysis of transition significantly predicted swimming velocity in all strokes except breaststroke (R2 ranging from 0.263 in front crawl to 0.364 in butterfly). The inter-limb coordination was a predictor in butterfly stroke (p = 0.006), whereas the body depth and inclination were predictors in the alternate strokes (front crawl (p = 0.05) and backstroke (p = 0.04)). These results suggest that the body position and coordinative swimming parameters (apart from kicking or stroking rate and length) have an important influence on the transition performance, which depends on the swimming strokes.post-print1076 K

Phytoremediation of outdoor air : a review

For the purpose of improving a country's economy, urbanization, industrialization, and technical advancement all had detrimental environmental effects. One of the most serious consequences of the aforementioned phenomenon is air pollution. Various air pollutants emitted by natural and anthropogenic sources have been found to have negative effects on the environment and human health after prolonged exposure. Insufficient technologies are used to reduce air pollution as a result of problems in the industry sector, including high maintenance costs, machine failure, and expensive technical equipment. Technological innovations like phytoremediation, which is sustainable and friendly to the environment, are being used to improve outdoor air quality. Cost efficiency, convenience of in-situ application, eco-friendly treatment, and the ability to improve the aesthetic value of the nearby environment are advantages of phytoremediation over other conventional remediation approaches. Numerous studies in the field of the outdoor air phytoremediation have found highly beneficial results, but also challenges in applying the suggested method. Plant tolerance to pollutants, environmental parameters, plant-specific features, composition of air pollutants, uncertainty in plant-microbe interactions, and plant antagonism have all emerged as a result of the use of plants in outdoor air pollution remediation. To become a complementary or alternative tool for engineering-based remediation methods, the remedy process must be optimized with supplementary treatments or the best combination junction with other methods must be found

Predictors of unfavourable outcome in aneurysmal subarachnoid haemorrhage

Background. Mortality rates following aneurysmal subarachnoid haemorrhage (aSAH) have decreased due to improvements in diagnoses and the management of complications, as well as early obliteration of the aneurysms. Neurogenic pulmonary oedema (NPO) is a clinical syndrome associated with an acute increase in intracranial pressure and a release of catecholamines into the circulation. This study investigated independent predictors of unfavourable outcomes (Glasgow Outcome Scores 1, 2 or 3) in patients with aSAH. Materials and methods. A total of 262 patients with aSAH (162 females) were included in this prospective study. Clinical characteristics were assessed, and electrocardiographic, serum cardiac and inflammatory biomarker measurements were recorded on admission. Outcomes were assessed three months after admission. Univariate and multivariate analyses of these data were used to predict unfavourable outcomes. Results. A total of 156 patients (59.54%) had unfavourable outcomes. Compared to those who had favourable outcomes, patients with unfavourable outcomes were significantly older (54.37 ± 10.56 vs. 49.13 ± 10.77 years; p < 0.001) and had more severe aSAHs (Hunt and Hess grades ≥ 3: 82.7% vs. 39.6%; p < 0.001). Patients with unfavourable outcomes were more likely to have NPO (10.3% vs. 2.8%; p = 0.023), hydrocephalus (34.0% vs. 20.8%; p = 0.02), and aneurysm reruptures (28.2% vs. 3.8%; p < 0.001).Independent predictors of an unfavourable outcome included Hunt and Hess grades ≥ 3 (odds ratio [OR], 4.291; 95% confidence interval [CI], 2.168–8.491; p < 0.001), increased systolic blood pressure on admission (OR, 1.020; 95% CI, 1.002–1.038; p = 0.03), increased heart rate (HR) on admission (OR, 1.024; 95% CI, 1.001–1.048; p = 0.04), and aneurysm rerupture (OR, 4.961; 95% CI, 1.461–16.845; p = 0.01).Conclusions. These findings suggest that aneurysm reruptures, as well as increased blood pressure and HR, are associated with unfavourable outcomes in patients with aSAH

How Should the Transition from Underwater to Surface Swimming Be Performed by Competitive Swimmers?

Despite the increasing importance of the underwater segment of start and turns in competition and its positive influence on the subsequent surface swimming, there is no evidence on how the transition from underwater to surface swimming should be performed. Therefore, the aim of the present study was to examine the role of segmental, kinematic and coordinative parameters on the swimming velocity during the pre-transition and transition phases. A total of 30 national male swimmers performed 4 × 25 m (one each stroke) from a push start at maximum velocity while recorded from a lateral view by two sequential cameras (50 Hz), and their kinematic and coordinative swimming parameters were calculated by means of two-dimensional direct linear transformation (DLT) algorithms. Unlike pre-transition, backward regression analysis of transition significantly predicted swimming velocity in all strokes except breaststroke (R2 ranging from 0.263 in front crawl to 0.364 in butterfly). The inter-limb coordination was a predictor in butterfly stroke (p = 0.006), whereas the body depth and inclination were predictors in the alternate strokes (front crawl (p = 0.05) and backstroke (p = 0.04)). These results suggest that the body position and coordinative swimming parameters (apart from kicking or stroking rate and length) have an important influence on the transition performance, which depends on the swimming strokes

K voprosu o Horvatskoj kirilliceskoj tradicii

Predmetom nastojaščej stat'i javjaetsja sbornik tezisov dokladov naučnoj konferencii Horvatskaja kirilličeskaja tradicija, sostojavšejsja v Zagrebe 26 i 27 dekabrja 2012 g. V stat'e osoboe vnimanie otvoditsja vzgljadam horvatskih i bosnijskih učastnikov konferencii, popytavšimsja peresmotret' rjad dokazannyh naučnyh položenij, otnosjaščihsja k istorii serbskoj kirillicy, i interpretirovat' ih, vopreki davno ustanovlennym faktam razvitija kirilličeskogo alfavita, v aktual'nom političeskom ključe

Transition phase – A new phase from start/turn to free swimming in competitive swimmers

For the best swimming performance, it is important to keep the highest possible velocity in each portion of the swimming event. Traditionally, the segments of swimming events are divided into: starting, free swimming and turning portions. Starting and turning mainly belong to underwater, while free swimming to surface swimming. The swimming process of transitioning from underwater to free swimming in this thesis is defined as breakout phase or transitioning swimming phase. Aim: The purpose of this study was to examine breakout phase in the four strokes and two genders regarding kinematics, coordination and segmental factors. This purpose was achieved through three main aims of the study. The first aim was to characterize the kinematics, coordinative and segmental variables of the breakout phase in elite competitive swimmers of both genders (Chapter 4). The second aim was to compare the kinematic and coordinative parameters of elite competitive swimmers during the transition phase and the free swimming phases (Chapter 5). The third aim was to examine the role of the segmental, kinematic and coordinative parameters on the swimming velocity during the pre-transition and transition phases of the push start (Chapter 6). Methods: 74 competitive swimmers (33 males and 41 females) with a personal best time within the 85% of world record participated in this study. Swimmers performed 4 x 25 m maximal efforts (one of each stroke in random order) from a push start and were recorded (50 Hz) by two sequential video cameras in sagittal plane. The average velocity, stroke length, stroke frequency, the relative duration (%) of the stroke phases, segmental variables (body and trunk inclinations, body depths) as well as the inter-limb discrete relative phases were calculated with direct linear transformation (DLT) algorithms for the breakout and free-swimming phases. Results (Study 1 – Chapter 4) Stroke rate was higher in males than in females in freestyle (F=10.24, p=0.002), backstroke (F=10.80, p=0.002) and breaststroke (F=4.70, p=0.034) during the transition phase. There was large effect of gender on transition inclinations, but only in butterfly (F=4.75, p=0.033) and breaststroke (F=4.75, p=0.033). Results (Study 2 – Chapter 5) In general terms, swimming velocity during breakout was faster (δ 0.27 ± 0.04 m/s, p < 0.001, ES = 0.33) than free-swimming (in all strokes but breaststroke), not because of a faster previous underwater kicking or a modified coordinative swimming pattern, but because of an increase in the stroking rate (δ 4.68 ± 0.79 cycles/min, p < 0.001, ES = 0.36), with changes to the relative duration of selected stroke phases. Results (Study 3 – Chapter 6) Body position and inter-limb coordinative parameters of competitive swimmers during transition phase predicted between the 15% and 29% of the variance in the average velocity. Body inclinations and depths were predictors in the alternate strokes (freestyle (p=0.05) and backstroke (p=0.04)), while coordinative parameters were predictor in butterfly stroke (p=0.006). Conclusion: Results indicate how swimmers manage the changing constraints during breakout and give clear applications for coaches on the key technical aspects that should be stressed when transitioning from underwater to surface swimming. ----------RESUMEN---------- Para obtener el mejor rendimiento en la natación, es importante mantener la mayor velocidad posible en cada una de las partes de la prueba. Tradicionalmente, los eventos de natación se dividen en: salida, nado y viraje. La salida y el viraje corresponden principalmente al nado subacuático, mientras que el nado se realiza en superficie. La transición del nado subacuático al nado en superficie en esta tesis se define como fase de transición de natación. Objetivo: El propósito de este estudio fue examinar la fase de transición en los cuatro estilos de competición con respecto a la cinemática, la coordinación y los factores segmentarios. Este objetivo se logró a través de estudios principales. El primer objetivo fue caracterizar la cinemática, las variables coordinativas y segmentarias de la fase de transición en nadadores competitivos en ambos géneros (Capítulo 4). El segundo objetivo fue comparar los parámetros cinemáticos y coordinativos de nadadores competitivos en la fase de transición y el nado en superficie (Capítulo 5). El tercer objetivo fue examinar el papel de los parámetros segmentarios, cinemáticos y coordinativos en la velocidad de nado durante las fases de pretransición y transición d (Capítulo 6). Métodos: 74 nadadores de nivel competitivo nacional (33 hombres y 41 mujeres) con una mejor marca personal en el 85% del récord mundial participaron en esta investigación mediante la firma del documento de consentimiento informado aprobado por el Comité de Ética de la Universidad Politécnica de Madrid y de acuerdo con a la Declaración de Helsinki. Los nadadores realizaron las pruebas en una piscina de 50x25 m. Se efectuaron 4x 25 m (uno de cada estilo en orden aleatorio) desde salida con empuje y se registraron (50 Hz) con dos cámaras de video secuenciales filmando en plano sagital. La velocidad media, la longitud de ciclo, la frecuencia de ciclo, la duración relativa (%) de las fases de la brazada, las variables segmentarias (inclinaciones del cuerpo y del tronco, profundidad del cuerpo) así como las fases relativas discretas entre las extremidades se calcularon por medio de algoritmos de Direct Linear Transformation (DLT) para las fases de transición y nado en superficie. Resultados (Estudio 1 - Capítulo 4) La frecuencia de ciclo difirió entre los géneros para el estilo libre (F = 10.24, p = 0.002), espalda (F = 10.80, p = 0.002) y braza (F = 4.70, p = 0.034) durante la fase de transición. El género de los deportistas tuvo un efecto significativo sobre la inclinación en la fase de transición, pero solo en los estilos mariposa (F = 4.75, p = 0.033) y braza (F = 4.75, p = 0.033). Resultados (Estudio 2 - Capítulo 5) En términos generales, la velocidad de nado durante la transición fue más rápida (δ 0.27 ± 0.04 m / s, p <0.001, ES = 0.33) que en el nado en superficie (en todos los estilos excepto en el braza), no debido a una batido subacuático previo más rápido o un patrón coordinativo modificado, pero debido a un aumento en la frecuencia de ciclo (δ 4.68 ± 0.79 ciclos / min, p <0.001, ES = 0.36), con cambios en la duración relativa de las fases de brazada seleccionadas. Resultados (Estudio 3 - Capítulo 6) La posición corporal y los parámetros de coordinación entre las extremidades de los nadadores de competición durante la fase de transición predijeron entre el 15% y el 29% de la varianza en la velocidad media de nado. Se demostró que las inclinaciones y la profundidad del cuerpo son más importantes para los estilos alternativos (crol (p=0.05) y espalda (p=0.04)), mientras que los parámetros coordinativos son elementos clave para el estilo mariposa (p=0.006). Conclusión: Estos resultados indican cómo los nadadores manejan los limitantes de la fase de transición y dan aplicaciones claras a los entrenadores en los aspectos técnicos clave aspectos que se deben enfatizar al hacer la transición del nado subacuático al nado en superficie

Gastrocnemius tendon length and strain are different when assessed using straight or curved tendon model

The present study investigated the effects of tendon curvature on measurements of tendon length using 3D-kinematic analysis. Curved and straight tendon models were employed for assessing medial gastrocnemius tendon length and strain during hopping (N = 8). Tendon curvature was identified using small reflective markers placed on the skin surface along the length of the tendon and a sum of vectors between the markers from the calcaneous up to the marker at the origin of tendon was calculated. The straight tendon was defined as a length of vector from the calcaneous to the marker at the origin of tendon. The curved tendon method yielded 5.0 ± 1.3 mm longer tendon (p < 0.001) than the straight tendon model. Tendon elongation was 2.1 ± 1.6 mm and peak strain 1.3 ± 0.7% smaller in curved than in straight tendon model (p < 0.01). The results suggest that the commonly used straight tendon model underestimate slightly but significantly the true tendon length but overestimate the strain and elongation.peerReviewe

Force synchrony enhances the stability of rhythmic multi-joint arm coordination

Although rhythmic coordination has been extensively studied in the literature, questions remain about the correspondence of constraints that have been identified in the related contexts of inter-limb and intra-limb coordination. Here we used a 2-DOF robot arm which allows flexible manipulation of forces to investigate the effect on coordination stability of intra-limb coordination of: (i) the synchrony of force requirements and (ii) the involvement of bi-functional muscles. Ten subjects produced simultaneous rhythmic flexion-extension (FE) and supination-pronation (SP) elbow movements in two coordination patterns: (1) flexion synchronized with supination/extension with pronation (in-phase pattern) and (2) flexion synchronized with pronation/extension with supination (anti-phase pattern). The movements were produced with five different settings of the robot arm: a neutral setting that imposed balanced force requirements, and four other settings that increased the force requirements for one direction in both DOF. When combined with specific coordination patterns, these settings created conditions in which either synchronous or alternate patterns of forcing were necessary to perform the task. Results showed that synchronous tasks were more stable than asynchronous tasks (P\ua

How should the transition from underwater to surface swimming be performed in competitive swimmers?

Despite the increasing importance of the underwater segment of start and turns in competition and its positive influence on the subsequent surface swimming, there is no evidence on how the transition from underwater to surface swimming should be performed. Therefore, the aim of the present study was to examine the role of segmental, kinematic and coordinative parameters on the swimming velocity during the pre-transition and transition phases. 30 national male swimmers performed 4 x 25 m (one each stroke) from a push start at maximum velocity while recorded from a lateral view by two sequential cameras (50 Hz), and their kinematic and coordinative swimming parameters were calculated by means of two-dimensional direct linear transformation (DLT) algorithms. Unlike pre-transition, backward regression analysis of transition significantly predicted swimming velocity in all strokes except breaststroke (R2 ranging from 0.263 in front crawl to 0.364 in butterfly). The inter-limb coordination was a predictor in butterfly stroke (p=0.006) whereas the body depth and inclination were predictors in the alternate strokes [front crawl (p=0.05) and backstroke (p=0.04)]. These results suggest that the body position and coordinative swimming parameters (apart from kicking or stroking rate and length) have an important influence on the transition performance, which depends on the swimming strokes