Magnitude and direction of shoulder torque asymmetries between different angular velocities in competitive swimmers.

Asymmetries in swimming can be the result of poor technique or coordination between limbs, reducing the ability to produce propulsive force and increasing resistive drag. Therefore, this study aimed to compare the magnitude and determine the consistency of isokinetic peak torque asymmetries between the angular velocities of in the shoulder joint movements of internal and external rotation, flexion, and extension. Twenty-one competitive swimmers performed concentric actions at 60°/s (3 repetitions) and 180°/s (20 repetitions) in the movements of internal and external rotation, flexion, and extension of the shoulders using an isokinetic dynamometer, with the peak torque and asymmetry index being common metrics across the tests. The results showed a greater magnitude of asymmetry in internal rotation (16.86 vs. 9.86; p = 0.007) and flexion (12.06 vs. 7.35; p = 0.008) at 60 vs. 180°/s, respectively. The agreement levels of the direction of asymmetries between angular velocities were fair to substantial (Kappa: 0.40 to 0.69). Evaluating isokinetic torque in different movements and angular velocities resulted in different levels of asymmetry. Muscle force asymmetries can impact propulsion efficiency and movement coordination during swimming. Understanding muscle asymmetries allows the development of targeted and individualised training programmes to correct strength imbalances.

Benefits and limitations of isokinetic force assessments in swimmer's shoulders: A systematic review.

OBJECTIVE: To indicate the benefits and limitations of the isokinetic test results for the performance of the main shoulder joint movements in swimmers, considering the different competitive levels, swimming techniques, race distances, and sex. METHODS: Search on the PubMed, CENTRAL, Medline, LILACS, and SCOPUS databases for the oldest records up to October 2022. Risk of bias, methodological quality, and level of evidence were evaluated based on the NHLBI checklist. RESULTS: 29 articles met the criteria and were included in this study. The quality analysis classified three as "good" and 26 as "regular", with a KAPPA index of 0.87. The main benefits found involved assessments of the clinical condition of the shoulder joint complex, relationships with performance, and reliability studies. The limitations found point to the participant's positioning in the instrument, use of angular velocity above 180°/s, and sample size. CONCLUSION: The use of the isokinetic dynamometer allows verifying the levels of strength, endurance, balance, and asymmetries among swimmers of different techniques, distances, competitive levels, and sex. Thus, it helps in the analysis and monitoring of the clinical conditions of swimmers' shoulder joints, contributing to the decision-making process of physiotherapists and coaches.

Swimmers' Effective Actions during the Backstroke Start Technique.

The analysis of the external forces of swimming starts has revealed how swimmers propel themselves out of the block, but data should be properly interpreted to fully understand force-generation mechanisms. This study aimed to assess horizontal and vertical forces in the backstroke start based on swimmers' structural and propulsive actions. Firstly, a simulated structural force was estimated by two transient backstroke-start inter-segmental realistic body positions: a maximally tucked position and an extended one (just before the hands-off and the take-off, respectively). Secondly, 10 competitive backstroke swimmers performed four 15 m maximal backstroke starts with the external forces estimated. Thirdly, the simulated structural force was subtracted from raw horizontal and vertical force data, measured between hands-off and take-off instants, resulting in the propulsive forces. The application of the algorithm has evidenced that backstrokers' horizontal and vertical simulated-structural-force components contributed to ~40% of total force during start propulsion (~0.2-0.12 s before the take-off), followed by the propulsive horizontal force increment and a progressive vertical component reduction (~0.05 s) with ~20° take-off angle. Based on these findings, researchers and coaches can better guide swimmers as to the proper mechanical strategies to achieve effectiveness in the backstroke start, and to improve direct transfer of resistance training programs.

Back plate and wedge use and individual ventral and dorsal swimming start performance: a systematic review.

Individual starts for ventral and dorsal swimming events have changed. After the introduction of back plate and wedge, some studies (mainly on ventral starts) have aimed to clarify their benefits and optimal application. This systematic review is aimed at a critical appraise of the literature on the main findings for back plate and wedge usage. We explored the databases of PubMed, Scopus and Web of Science and conducted a manual search on the reference list of papers. We based our search on the quality scale of the National Health Institutes and found 25 studies that met the eligibility criteria and that scored 7.75 ± 1.18 and 8.0 ± 0.71 on fair-quality studies addressing kick and backstroke starts. Kick start has shown faster start time comparing with grab and track starts by reducing block time and increasing horizontal take-off velocity. Backstroke start using the wedge improved performance through a greater centre of mass vertical position at take-off, horizontal and vertical position at entry and underwater velocity. Swimmers have adopted technical variants of kick and backstroke start by changing block set-up and stance, which should be monitored considering anthropometrics and strength abilities.

Modeling and predicting the backstroke to breaststroke turns performance in age-group swimmers.

The purpose of the present study was to identify the performance determinant factors predicting 15-m backstroke-to-breaststroke turning performance using and comparing linear and tree-based machine-learning models. The temporal, kinematic, kinetic and hydrodynamic variables were collected from 18 age-group swimmers (12.08 ± 0.17 yrs) using 23 Qualisys cameras, two tri-axial underwater force plates and inverse dynamics approach. The best models were obtained: (i) with Lasso linear model of the leave-one-out cross-validation in open turn (MSE = 0.011; R2 = 0.825) and in the somersault turn (MSE = 0.016; R2 = 0.734); (ii) the Ridge of the leave-one-out cross-validation (MSE = 0.016; R2 = 0.763) for the bucket turn; and (iii) the AdaBoost tree-based model of the leave-one-out cross-validation for the crossover turn (MSE = 0.016; R2 = 0.644). Model's selected features revealed that optimum turning performance was very similarly determined for the different techniques, with balanced contributions between turn-in and turn-out variables. As a result, the relevant feature's contribution of each backstroke-to-breaststroke turning technique are specific; developing approaching speed in conjunction with proper gliding posture and pull-out strategy will result in improved turning performance, and may influence differently the development of specific training intervention programmes.

Relative age in Brazilian swimmers and para swimmers / Idade relativa em nadadores e paranadadores brasileiros

abstract This study aimed to analyze the relationships between swimming competitive events, functional classification and relative age and to detect if the relative age affects performance in Brazilian swimmers and para swimmers. Data were retrieved from public databases and birth dates were classified in four quartiles (Q1 = January-March; Q2 = April-June; Q3 = July-September; Q4 = October-December). Descriptive statistics, Chi-square tests and ANOVA were used. The 50 m freestyle is the competitive event with 2349 swimmers, followed by 100 m (n = 1817) and 200 m freestyle (n = 905), and 200 m butterfly with 42 swimmers. Para swimmers are mainly distributed to S14, S6 and S5 functional classes (n = 140, 87 and 45), and individual medley events were less represented at SM3, SM9 and SM11 (n = 1 swimmer). Most of swimming events (86.36%) and para swimming functional classes (51.43%) are represented by swimmers and para swimmers born in the first and second quartiles. Moderate associations between functional classification and relative age were observed (p < 0.0001, Cramer's V = 0.277). No effects of relative age on swimmers and para swimmers' performance were noticed (p > 0.05). The great functional class seems to be related to great para swimmers' relative age. Quartiles distribution shows the advantage of being born in the first months of the year to be registered among the most talented Brazilian swimmers and para swimmers.

resumo Este estudo teve como objetivo analisar as relações entre eventos competitivos de natação, classificação funcional e idade relativa e detectar se a idade relativa afeta o desempenho em nadadores e paranadadores brasileiros. Os dados foram recuperados de bancos de dados públicos e as datas de nascimento foram classificadas em quatro quartis (Q1 = janeiro-março; Q2 = abril-junho; Q3 = julho-setembro; Q4 = outubro-dezembro). Utilizou-se estatística descritiva, teste Qui-quadrado e ANOVA. Os 50 m livre é a prova competitiva com 2.349 nadadores, seguido de 100 m (n = 1.817) e 200 m livre (n = 905), e 200 m borboleta com 42 nadadores. Os paranadadores estão distribuídos principalmente nas classes funcionais S14, S6 e S5 (n = 140, 87 e 45), e as provas individuais de medley foram menos representadas em SM3, SM9 e SM11 (n = 1 nadador). A maioria das provas de natação (86,36%) e classes funcionais de paranatação (51,43%) são representadas por nadadores e paranadadores nascidos no primeiro e segundo quartis. Associações moderadas entre classificação funcional e idade relativa foram observadas (p < 0,0001, V de Cramer = 0,277). Não foram observados efeitos da idade relativa no desempenho de nadadores e paranadadores (p > 0,05). A grande classe funcional parece estar relacionada com a idade relativa dos grandes paranadadores. A distribuição por quartis mostra a vantagem de ter nascido nos primeiros meses do ano para ser registrado entre os mais talentosos nadadores e paranadadores brasileiros.

Backstroke-to-Breaststroke Turns Muscular Activity. A Study Conducted in Age Group Swimmers.

The aims of this study were to compare surface electromyographic (EMG) activity and kinematic variables among open, somersault, bucket and crossover backstroke-to-breaststroke turning techniques, and identify relationships between the integrated electromyography (iEMG) and kinematics profile focusing on the rotation and push-off efficacy. Following a four-week of systematically increasing contextual interference intervention program, eight 12.38 ± 0.55 years old male swimmers randomly performed twelve repetitions (three in each technique) turns in and out of the wall at maximum speed until the 7.5 m reference mark. Surface EMG values of the right vastus lateralis, biceps femoris, tibialis anterior, gastrocnemius medialis, rectus abdominis, external oblique, erector spinae and latissimus dorsi were recorded and processed using the integrated electromyography (iEMG) and the total integrated electromyography (TiEMG) that was expressed as a percentage of iEMGmax to normalize per unit of time for each rotation and push-off phase. Complementarily, 2D sagittal views from an underwater video camera were digitized to determine rotation and push-off efficacy. The crossover turn presented the highest rotation and push-off iEMG values. Erector spinae and gastrocnemius medialis had the highest activity in the rotation and push-off phases (89 ± 10 and 98 ± 69%, respectively). TiEMG depicted a very high activity of lower limb muscles during push-off activity (222 ± 17 to 247 ± 16%). However, there were no relation between TiEMG and rotation and push-off time, tuck index and final push-off velocity during the rotation and the push-off phases across all the studied turning techniques. The rotation efficacy in age-group swimmers were dependent on rotation time (p = 0.04). The different turning techniques were not distinguishable regarding iEMG activity as a possible determinant of rotation and push-off efficacy. Our study has direct implications for selecting appropriate exercises and designing training programs for optimizing the rotation and push-off phases of backstroke-to-breaststroke turning at young ages.

Biomechanical Features of Backstroke to Breaststroke Transition Techniques in Age-Group Swimmers.

This study aimed to identify the biomechanical features of backstroke to breaststroke transition techniques (open, somersault, bucket, and crossover) in age-group swimmers. Eighteen preadolescent swimmers (12.2 ± 0.4 years old and 3-4 Tanner stages) underwent 4 weeks of systematic contextual interference training, comprising 16 sessions (40 min·session-1). Soon after, experimental testing was conducted where swimmers randomly performed 12 × 15 m maximal turns (composed of 7.5 m turn-in and 7.5 m turn-out of the wall segments), three in each transition technique. Kinematical, kinetic, and hydrodynamic variables were assessed with a dual-media motion capture system (12 land and 11 underwater cameras), triaxial underwater force plates, and inverse dynamics. Variables were grouped in turn-in (approach and rotation) and turn-out (wall contact, gliding, and pull-out) phases, with factor analysis used to select the variables entering on multiple regressions. For the turn-in phase, 86, 77, 89, and 87% of the variance for open, somersault, bucket, and crossover turning techniques, respectively, was accounted by the 7.5 and 2.5 m times, mean stroke length, and rotation time. For the turn-out phase, first gliding distance and time, second gliding depth, turn-out time, and dominating peak_Z push-off force accounted for 93% in open turn, while wall contact time, first gliding distance, breakout distance and time, turn-out time, dominating peak_Y push-off force, and second gliding drag coefficient accounted for 92% in a somersault turn. The foot plant index, push-off velocity, second gliding distance, and turn-out time accounted for 92% in bucket turn while breakout and turn-out time, non-dominating peak_Y and peak_Z push-off force, first and second gliding drag force and second gliding drag coefficient accounted for 90% in crossover turn, respectively. The findings in this study were novel and provided relevant biomechanical contribution, focusing on the key kinematic-temporal determinant during turn-in, rotation, and push-off efficacy, and the kinetic and hydrodynamic during turn-out, which would lead to improved backstroke to breaststroke transition techniques in 11-13 years-old age-group swimmers.

Backstroke to Breaststroke Turning Performance in Age-Group Swimmers: Hydrodynamic Characteristics and Pull-Out Strategy.

We compared the hydrodynamic characteristics and pull-out strategies of four backstroke-to-breaststroke turning techniques in young swimmers. Eighteen 11 and 12-year-old swimmers participated in a 4 week intervention program including 16 contextual interference sessions. The hydrodynamic variables were assessed through inverse dynamics, and the pull-out strategy kinematics were assessed with tracking markers followed by 12 land cameras and 11 underwater cameras. Swimmers randomly completed sixteen 30 m maximal backstroke-to breaststroke-open, somersault, bucket and crossover turns (four in each technique) with a 3 min rest. The data showed higher drag force, cross-sectional area and drag coefficient values for the first (compared with the second) gliding position. The crossover turn revealed the highest push-off velocity (2.17 ± 0.05 m·s-1), and the somersault turn demonstrated the lowest foot plant index (0.68 ± 0.03; 68%), which could have affected the first gliding, transition and second gliding depths (0.73 ± 0.13, 0.86 ± 0.17 and 0.76 ± 0.17 m). The data revealed the consistency of the time spent (4.86 ± 0.98 s) and breakout distance (6.04 ± 0.94 m) among the four turning techniques, and no differences were observed between them regarding time and average velocity up to 7.5 m. The hydrodynamic characteristics and pull-out strategy of the backstroke-to-breaststroke turns performed by the age group swimmers were independent of the selected technique.

Lateral kinetic proficiency and asymmetry in backstroke start performed with horizontal and vertical handgrips.

We aimed to compare preferred, non-preferred, hand, foot kinetics and their asymmetry in two backstroke start variants. Complementarily, asymmetries were correlated to the resultant take-off velocity. Nine swimmers completed four 15 m backstroke starts with horizontal handgrips and four with vertical handgrips on an instrumented block (right, left hand, foot forces and impulse, normalised to swimmers' weight and time). We applied handedness and footedness questionnaires. Preferred hand and foot depicted a very and most likely moderate to large increase on horizontal force before hands-off (-0.51 ± 0.10; -0.47 ± 0.10; 0.87 ± 0.15; 0.90 ± 0.18 (N/N)) and a very and most likely large to very large increase on horizontal impulse (-0.28 ± 0.05; -0.26 ± 0.04; 0.50 ± 0.03; 0.51 ± 0.04 (N/N)*(s/s)) in both variants. Non-preferred hand and foot showed a very likely large to moderate increase (95% to 99%) on vertical and lateral impulse (0.30 ± 0.03; 0.31 ± 0.03; 0.07 ± 0.04; 0.05 ± 0.03 (N/N)*(s/s)) in both variants. The horizontal handgrip demonstrated likely moderate greater horizontal forces asymmetry on hands in the starting signal (-20.39 ± 7.16 (N/N), 92%), before hands-off (-71.46 ± 24.48 (N/N), 90%) and impulse asymmetry (-21.13 ± 5.80 (N/N), 94%). Asymmetry and resultant take-off velocity in both variants were strongly associated (r = -0.733 and -0.833 for feet horizontal impulse). Kinetics lateralisation was noticed in backstroke start and asymmetry hampers desirable performance.

Refugios diurnos del murciélago Rhynchonycteris naso (Chiroptera: Emballonuridae) en Laguna de Términos, Campeche, México / Diurnal roosts of the bat Rhynchonycteris naso (Chiroptera: Emballonuridae) in Laguna de Términos, Campeche, Mexico

Introducción: La selección de refugios diurnos es un proceso crucial para los murciélagos debido a su influencia en la ecología, organización social y supervivencia de sus poblaciones. El murciélago narigón (Rhynchonycteris naso) es una especie protegida por leyes de México, cuyos refugios y zonas de forrajeo, están estrictamente asociados a cuerpos de agua, principalmente ríos. Por lo tanto, cambios en la calidad del agua suponen un riesgo para sus poblaciones. Sin embargo, el conocimiento sobre el estado actual de sus poblaciones y refugios diurnos en México, es escaso. Objetivo: Ubicar y describir los refugios diurnos de R. naso y evaluar la relación del tamaño del grupo de murciélagos con las características de los refugios, la salinidad y el pH del agua donde habitan. Métodos: De marzo a octubre 2015, se realizaron búsquedas de refugios diurnos mediante recorridos en lancha a lo largo de ríos, arroyos y lagunas, en once sitios del Área de Protección de Flora y Fauna Laguna de Términos, Campeche México. Por cada refugio localizado se registró el tamaño del grupo y su acomodo en el refugio, el tipo de refugio, el tipo de vegetación, la cobertura, la distancia entre refugios, el diámetro del tronco, la salinidad y el pH. Para investigar el efecto de las variables registradas en los refugios sobre el tamaño de cada grupo, se ajustaron Modelos Lineales Generalizados. Resultados: Encontramos 48 refugios en troncos secos, cortezas de árboles y puentes, asociados a cuerpos de agua dulce y oligohalina, principalmente en vegetación de manglar. El promedio (± EE) del tamaño del grupo fue de 5.3 ± 0.48 para los refugios naturales y de 22.6 ± 9.54 para los artificiales. Encontramos una relación significativa con el tipo de refugio, el tipo de vegetación y el diámetro del tronco. Los refugios con tamaño de grupo mayores presentaron un acomodo agregado. Se localizaron 40 refugios sobre cuerpos de agua dulce y ocho en oligohalina con alto nivel de agrupamiento. Conclusiones: La mayor incidencia de refugios en sitios de agua dulce y ligeramente ácida, es explicada bajo la teoría del óptimo forrajeo. Debido a que el área de estudio se encuentra en el límite de su distribución, el manglar representa el tipo de vegetación más importante para garantizar la permanencia de las poblaciones de R. naso. Adicionalmente, debido a que en algunas porciones de la zona de estudio no fue posible encontrar refugios, es crucial llevar a cabo estudios sobre la calidad del agua y los niveles de contaminación en la región. Este estudio proporciona información relevante sobre las poblaciones del murciélago Rhynchonycteris naso con implicaciones directas sobre su conservación en zonas ribereñas y humedales costeros.

Introduction: The selection of day-roost is a crucial process for bats because it influences the ecology, social organization, and survivorship aspects of their populations. Proboscis bat (Rhynchonycteris naso) is a protected species by Mexican law, whose foraging and roosting areas are strongly associated with bodies of water, primarily rivers. Therefore, alterations in the water quality pose a risk to their populations. However, knowledge of the current state of their populations and roosting ecology is very poor in Mexico. Objectives: To locate and to describe R. naso's diurnal roosts, and to evaluate the relationship of the group size per roost with the characteristics of the diurnal roost, the salinity and pH of the water where they inhabit. Methods: From March to October 2015, we searched diurnal roost through boat tours along rivers, streams, and lagoons, in eleven sites in the Laguna de Términos Flora and Fauna Protection Area, Campeche, Mexico. For each localized roost, we recorded the group size, and their spatial distribution, the type of roost and vegetation, the distance between roosts, the diameter of trunk, the salinity, and pH. In order to investigate the effect of the variables recorded in diurnal roost on size group, generalized linear models were adjusted. Results: We found 48 diurnal roost in dead tree-trunks, tree bark and bridges, associated with freshwater, and oligohaline bodies, mainly in mangrove vegetation. The average size of the groups was 5.3 ± 0.48 and 22.6 ± 9.54 in natural and artificial roosts, respectively. We found a significant relationship with the type of roost, type of vegetation and diameter of trunk. Roosts with larger groups of bats presented an aggregated distribution. We located 40 diurnal roosts on freshwater bodies and eight in oligohaline with a high grouping level. Conclusions: Greater incidence of roost in fresh and lightly acid water is explained under optimal foraging theory. Because the study area is found in the limit of their distribution, mangrove is a very important vegetation type to guarantee the establishment of R. naso populations. Also, due no roosts were found in some portions of the study zone, quality of water, and contaminant level studies are crucial. This study provides relevant information on their populations with direct implications for the conservation in coastal areas.

Evaluation isometric and isokinetic of trunk flexor and extensor muscles with isokinetic dynamometer: A systematic review.

OBJECTIVE: To systematically review the literature analyzing the reliability and characteristics of the protocols of isokinetic and isometric evaluation of the trunk flexor and extensor muscles with isokinetic dynamometer. METHODS: This is a systematic review using PubMed, CENTRAL, LILACS, PEDro and SCOPUS databases, searching the oldest records up to December 2019. The risk of bias, the methodological quality and the level of evidence were evaluated using the COSMIN checklist. RESULTS: Fourteen articles have met the criteria and have been included in this study. All the articles performed an isometric or isokinetic evaluation of the trunk muscles with the isokinetic dynamometer and presented an analysis of the protocol's reliability using the intraclass correlation coefficient. Five articles had excellent reliability (0.93-0.98). Most of the studies presented doubtful and inconsistent psychometric values for reliability, because they used a short period between tests. The level of evidence to the fourteen selected articles for reliability was moderate. CONCLUSIONS: Although the studies present limitations in methodological quality, it was possible to identify highly reliable patterns in the parameters employed and to present recommendations for the assessment of trunk flexor and extensor muscles in the isokinetic dynamometer, both for assessment in the sitting position and orthostatic.

Diversidad de murciélagos en la selva baja inundable del sureste de México

Introducción: El tintal es un tipo de selva baja inundable característico del sureste de México, donde la especie dominante es el palo de tinte (Haematoxylum campechianum L.). Por sus características estructurales y las condiciones de las áreas donde se desarrollan, los tintales pueden funcionar como un hábitat crítico para muchas especies animales. Objetivo: El objetivo de esta investigación fue describir la diversidad local y regional de la quiropterofauna presente en tintales de diferentes áreas del sureste mexicano. Métodos: Se trabajó en ocho localidades con presencia de tintal en los estados de Campeche y Tabasco. En cada una se colocaron seis redes de nylon durante tres noches. Se calculó la riqueza observada y la estimada para cada localidad, así como la abundancia total. Se elaboraron curvas de rango de abundancia y de acumulación de especies. Se realizaron análisis de similitud entre localidades y se correlacionaron estas similitudes con la distancia geográfica entre ellas. Resultados: Se registraron 25 especies de murciélagos pertenecientes a cinco familias, de las cuales Phyllostomidae fue la mejor representada. La mayoría de las especies fueron insectívoras (44 % del total), mientras los frugívoros fueron los más abundantes. Entre estas destacan Artibeus lituratus y A. jamaicensis, las cuales se registraron en un mayor número de localidades. Mientras tanto, Glossophaga soricina fue la más abundante. En Oxpemul, se registró la mayor riqueza de especies (N= 12) y en Las Bodegas la menor (N= 4), aunque esta fue la tercera localidad con mayor cantidad de individuos. La riqueza estimada de especies para toda el área, según nuestros datos, osciló entre 29 y 34. Los ensamblajes menos equitativos fueron Las Bodegas y Tres Brazos. Las localidades más semejantes entre sí en cuanto a la estructura de la comunidad fueron La Toza y Las Bodegas y, en cuanto a la composición de especies Oxpemul y Atasta. Las similitudes entre las localidades no estuvieron correlacionadas con la cercanía geográfica. Conclusiones: La mayoría de las localidades de estudio están altamente antropizadas, pero la tolerancia de varias especies de murciélagos a estas modificaciones del paisaje les ha permitido hacer uso de estas. La elevada abundancia de las especies consumidoras de frutos encontrada apoya la idea de la importancia de los murciélagos en la recuperación de la vegetación arbórea en zonas alteradas del sureste de México y el valor de los tintales dentro de estas áreas para la conservación de la biodiversidad.

Introduction: The "tintal" is a type of seasonally inundated forest where the dominant species is Haematoxylum campechianum L. Due to its structural characteristics and the conditions of the areas where it develops, it could work as a critical habitat for many animal species. Objective: This work aimed at describing the regional and local diversity of the chiropterofauna inhabiting tintal along different areas in the Southeastern Mexico. Methods: The research was carried out in eight localities with presence of tintal in the states of Campeche and Tabasco, Mexico. In each site, six mist nets were placed during three nights. The observed and expected richness were calculated for each site, as well as the total abundance. Rank-abundance and species accumulation curves were generated. Similarity analyses between localities were performed and correlated with the geographical distance between them. Results: We recorded 25 bat species belonging to five families, where Phyllostomidae was the most represented. Most registered species were insectivorous (44 % of the total), while frugivorous were the most abundant. Frugivorous Artibeus lituratus and A. jamaicensis were the species recorded in a greater number of localities, and Glossophaga soricina was the most abundant. The highest richness of species was registered in Oxpemul (N= 12), while in Las Bodegas we found the lowest (N= 4), although the latter was the third locality with the highest number of individuals. The estimated richness of species for the whole area varied between 29 and 34. The least even assemblages were Las Bodegas and Tres Brazos. The most similar localities in terms of the structure of the assemblages were La Toza and Las Bodegas and, in terms of the species composition, Oxpemul and Atasta. The similarities between the localities were not correlated with geographical proximity. Conclusions: Most of the researched localities were highly anthropized, but the tolerance of several bat species to these landscape modifications has allowed them to make use of such areas. The high abundance of the frugivorous species registered supports that bats may play a key role in the recovery of tree vegetation in altered areas in Southeastern Mexico, and emphasizes the value of the tintal along this area for the conservation of biodiversity.

Is the rating of perceived exertion planned by the personal trainer similar to subject's perception? A pilot study / A percepção subjetiva de esforço planejada pelo treinador personalizado é similar à do aluno? Um estudo piloto

Abstract The present study aimed to compare the intensity planned by the Personal Trainers (PTs) with that perceived by subjects in resistance training. Six male and female practicing resistance training (4 males and 2 females with mean age 33.0 ± 6.16 years, 1.3 ± 0.55 years training with follow-up) and two PTs participated in the study (average 32.0 ± 4.0 years, postgraduates, with a five -year or more experience). The comparison between the intensity planned by the PT and the intensity experienced by the subjects was determined by the Rating of Perceived Exertion (RPE). Previously, at the beginning of each training, the PT should respond individually to the RPE estimated for each student in that training session. At the end of each session, 30 minutes after its completion, this same scale was answered by the subjects. To compare the intensity of the sessions perceived by the subjects and that planned by the PTs, we used descriptive statistics, standardized mean differences and their confidence intervals. Results have showed that subjects reported substantially higher intensities (small effect size) when compared to PTs. It has been concluded that the intensity experienced by the subjects was substantially higher than that planned by the PTs.

Resumo Objetivou-se comparar a intensidade planejada pelos treinadores personalizados com a percebida por alunos no treinamento resistido. Participaram do estudo seis praticantes de treinamento resistido (4 homens e 2 mulheres; média de idade 33,0 ± 6,16 anos, 1,3 ± 0,55 anos treinando com acompanhamento) e dois treinadores personalizados (média de 32,0 ± 4,0 anos, pós-graduados, com experiência acima de cinco anos atuando como treinador personalizado. A comparação entre a intensidade planejada pelo treinador personalizado e a intensidade experienciada pelos alunos foi realizada através da aplicação da escala de percepção subjetiva do esforço (PSE). Previamente, ao início de cada treino, o treinador personalizado respondeu individualmente a PSE estimada para cada aluno naquela sessão de treinamento, e ao final de cada sessão, 30 minutos após seu término, esta mesma escala era respondida pelos alunos. Para a comparação entre a intensidade das sessões percebidas pelos alunos e a planejada pelos treinadores utilizamos as diferenças de médias estandardizadas, intervalos de confiança. Houve diferença substancial entre a PSE pretendida pelos treinadores personalizados e a experienciada pelos alunos no treinamento resistido. A intensidade percebida pelos praticantes foi maior do que a planejada pelos treinadores personalizados.

Body fat percentage and lower limbs temperature in recreational cyclists during an incremental test / Porcentagem de gordura e temperatura dos membros inferiores em ciclistas recreativos durante teste incremental

This study aimed to evaluate temperature variations on the thighs in an incremental cycling test in healthy recreational cyclists with two different fat percentages. Thirty-two male recreational cyclists were measured in height, body mass, thigh skinfold and body fat percentage, and from the body fat percentage were divided into two groups, Group 1: 16 cyclists who presented body fat percentage < 24% and Group 2: 16 cyclists who presented body fat percentage > 24%. Three thermographic photos were taken, before (Pre), just after (Post) and after 10 min (Post10) of the incremental cycling test to determine mean temperature of right and left Vastus Lateralis, Rectus Femoris and Biceps Femoris. Temperature variations were defined as the difference among the three moments: (i) var1 = Post-Pre, (ii) var2 = Post10- Pre and (iii) var3 = Post10-Post. Differences between groups and moments were calculated using magnitude-based inferences. Group 1 evidenced a very likely large increase in the cycling peak power output. Group 2 showed a likely and most likely moderate, large and very large increase in age, body mass and fat. Group 1 depicted a very likely to likely moderate temperature increase in the right and left Vastus Lateralis, Rectus Femoris and Biceps Femoris on Post10 compared to Post effort moment. Both groups depicted a very likely and most likely moderate and large temperature decrease of right and left Biceps Femoris on Pre compared to Post effort. Percentage of fat seems to discreetly influence skin temperature response, finding that might not be observed when we evaluate trained cyclists exhibiting different percentages of fat....(AU)

Este estudo objetivou a avaliar as variações de temperatura das coxas em um teste incremental de ciclismo em ciclistas recreacionais saudáveis com dois diferentes percentuais de gordura. Trinta e dois ciclistas recreacionais do sexo masculino foram avaliados em estatura, massa corporal, dobras cutâneas da coxa e percentual de gordura corporal, e, a partir do percentual de gordura corporal, foram divididos em dois grupos, Grupo 1: 16 ciclistas que apresentaram percentual de gordura corporal < 24% e Grupo 2: 16 ciclistas que apresentaram percentual de gordura corporal > 24%. Foram tiradas três fotos termográficas, antes (Pré), logo após (Pós) e após 10 min (Pós10) do teste de ciclismo para determinar a temperatura média do Vasto Lateral, Reto Femoral e Bíceps Femoral direito e esquerdo. As variações de temperatura foram definidas como a diferença entre os três momentos: (i) var1 = Pós-Pré, (ii) var2= Pós10-Pré e (iii) var3= Pós10-Pós. Diferenças entre grupos e momentos foram calculadas usando inferências baseadas em magnitude. Grupo 1 apresentou um provável a muito provável aumento moderado da temperatura para os Vastos Laterais direito e esquerdo, o Reto Femoral e o Bíceps Femoral no Pós10 em comparação com o momento pós-esforço. Grupo 2 mostrou aumentos provável e muito provável moderado, grande e muito grande na idade, massa corporal e gordura. Ambos os grupos descreveram uma muito provável e mais provável moderada e grande queda de temperatura do Bíceps Femoral direito e esquerdo no Pré comparado ao Pós-esforço. Percentagem de gordura parece influenciar discretamente a resposta da temperatura da pele, resultado que poderá não ser observado quando avaliados ciclistas treinados que apresentam diferentes percentagens de gordura....(AU)

Predicting centre of mass horizontal speed in low to severe swimming intensities with linear and non-linear models.

We aimed to compare multilayer perceptron (MLP) neural networks, radial basis function neural networks (RBF) and linear models (LM) accuracy to predict the centre of mass (CM) horizontal speed at low-moderate, heavy and severe swimming intensities using physiological and biomechanical dataset. Ten trained male swimmers completed a 7 × 200 m front crawl protocol (0.05 m.s-1 increments and 30 s intervals) to assess expiratory gases and blood lactate concentrations. Two surface and four underwater cameras recorded independent images subsequently processed focusing a three-dimensional reconstruction of two upper limb cycles at 25 and 175 m laps. Eight physiological and 13 biomechanical variables were inputted to predict CM horizontal speed. MLP, RBF and LM were implemented with the Levenberg-Marquardt algorithm (feed forward with a six-neuron hidden layer), orthogonal least squares algorithm and decomposition of matrices. MLP revealed higher prediction error than LM at low-moderate intensity (2.43 ± 1.44 and 1.67 ± 0.60%), MLP and RBF depicted lower mean absolute percentage errors than LM at heavy intensity (2.45 ± 1.61, 1.82 ± 0.92 and 3.72 ± 1.67%) and RBF neural networks registered lower errors than MLP and LM at severe intensity (2.78 ± 0.96, 3.89 ± 1.78 and 4.47 ± 2.36%). Artificial neural networks are suitable for speed model-fit at heavy and severe swimming intensities when considering physiological and biomechanical background.

Eccentric flywheel post-activation potentiation influences swimming start performance kinetics.

This study aimed to assess the effects of post-activation potentiation in the strength related variables of a kick start. Thirteen competitive swimmers performed three kick starts after a standardized warm up (denoted USUAL) and another after inducing post-activation through five isotonic repetitions on an eccentric flywheel (denoted PAP). A T-test was used to quantify differences between USUAL and PAP warm up. The best trial of each subject achieved by natural conditions (denoted PEAK) was compared with data obtained after PAP. An instrumented starting block with independent triaxial force plates, collected the strength variables related with the impulse at take off. Improvements in the vertical components of force were observed after PAP compared with USUAL, meanwhile no differences were detected on the horizontal components of it. The velocity at take off was higher after PAP compared with USUAL (4.32 ± 0.88 vs 3.93 ± 0.60 m*s-1; p = 0.02). No differences in force or velocity were detected comparing PAP with PEAK (4.13 ± 0.62 m*s-1, p = 0.11). The PAP warm-up increased vertical force and it was transferred to a higher resultant velocity at take-off. This improvement would equal the best result possible obtained in natural conditions after some trials.

Physiological and neuromuscular responses during the game in female futsal players / Respostas neuromusculares e fisiológicas durante o jogo em atletas de futsal feminino

ABSTRACT This study has evaluated the differences in the physiological and neuromuscular responses in female futsal athletes during a friendly game. Sample comprised six female futsal players (21.8 ± 3.9 years; 57.4 ± 4.1 kg; 159.0 ± 2.7 cm height; 19.0 ± 3.3% body fat and 7.8 ± 1.8 years of practice). Heart rate (HR) was monitored during the whole game. Coutermovement Jump (CMJ), Resistance Explosive Power (REP) lower limb and blood lactate have been evaluated before and after the final of the first and second periods. To compare physiological and neuromuscular variables between the different moments we have used standardized mean difference (SMD), confidence interval (CI = 90%) and the probabilities of differences with clinical relevance. Maximal heart rate (HRmax) was 186.6 ± 10.6 and 185.8 ± 8.3, first and second periods, respectively. There has been a substantial lactate increasing in the moment prior to the start of the game to the final of the first (2.1 ± 0.3 to 6.3 ± 2.3 mmol/L-1, SMD = 5.25 (3.28: 7.21), 100/0/0; most likely) and the second periods (2.1 ± 0.3 to 5.4 ± 1.3 mmol/L-1, SMD = 4.62 (3.19: 6.04), 100/0/0; most likely). Although there has been an increase in blood lactate, the performance of female futsal players was not suppressed during and immediately after a friendly game, suggesting that the neuromuscular system may be restored immediately after the end of the game.

RESUMO O presente estudo testou se existem diferenças, nas respostas fisiológicas e neuromusculares em atletas de futsal durante um jogo amistoso. A amostra foi composta por seis atletas de futsal do sexo feminino (21,8 ± 3,9 anos; 57,4 ± 4,1 kg; 159,0 ± 2,7 cm de altura; 19,0 ± 3,3% gordura corporal e 7,8 ± 1,8 anos de tempo de prática). A frequência cardíaca (FC) foi monitorada durante toda a partida. O salto com contramovimento, resistência de força explosiva de membros inferiores e lactato sanguíneo foram avaliados antes, após o final do primeiro e segundo tempo de jogo. Para comparação das variáveis neuromusculares e fisiológicas entre os diferentes momentos, nós utilizamos as diferenças de médias estandardizadas (DME), intervalo de confiança (IC = 90%) e probabilidades de haver diferenças com relevância clínica. A FC máxima (FCmáx) foi de 186,6 ± 10,6 e 185,8 ± 8,3, primeiro e segundo tempo, respectivamente. Houve um aumento substancial do lactato do momento que antecedeu o início da partida para o final do primeiro (2,1 ± 0,3 para 6,3 ± 2,3 mmol/L-1, DME = 5,25 (3,28: 7,21), 100/0/0; most likely) e segundo tempo (2,1 ± 0,3 para 5,4 ± 1,3 mmol/L-1, DME = 4,62 (3,19: 6,04), 100/0/0; most likely) de partida. Embora tenha ocorrido um aumento do lactato sanguineo, a performance de atletas femininas de futsal não foi suprimida durante e logo após uma partida amistosa, sugerindo que, o sistema neuromuscular possa estar restaurado logo após o término do jogo.

Modelling and Predicting Backstroke Start Performance Using Non-Linear and Linear Models.

Our aim was to compare non-linear and linear mathematical model responses for backstroke start performance prediction. Ten swimmers randomly completed eight 15 m backstroke starts with feet over the wedge, four with hands on the highest horizontal and four on the vertical handgrip. Swimmers were videotaped using a dual media camera set-up, with the starts being performed over an instrumented block with four force plates. Artificial neural networks were applied to predict 5 m start time using kinematic and kinetic variables and to determine the accuracy of the mean absolute percentage error. Artificial neural networks predicted start time more robustly than the linear model with respect to changing training to the validation dataset for the vertical handgrip (3.95 ± 1.67 vs. 5.92 ± 3.27%). Artificial neural networks obtained a smaller mean absolute percentage error than the linear model in the horizontal (0.43 ± 0.19 vs. 0.98 ± 0.19%) and vertical handgrip (0.45 ± 0.19 vs. 1.38 ± 0.30%) using all input data. The best artificial neural network validation revealed a smaller mean absolute error than the linear model for the horizontal (0.007 vs. 0.04 s) and vertical handgrip (0.01 vs. 0.03 s). Artificial neural networks should be used for backstroke 5 m start time prediction due to the quite small differences among the elite level performances.