Assessment of ultrafine particles in Portuguese preschools: levels and exposure doses

The aim of this work was to assess ultrafine particles (UFP) number concentrations in different microenvironments of Portuguese preschools and to estimate the respective exposure doses of UFP for 3–5-year-old children (in comparison with adults). UFP were sampled both indoors and outdoors in two urban (US1, US2) and one rural (RS1) preschool located in north of Portugal for 31 days. Total levels of indoor UFP were significantly higher at the urban preschools (mean of 1.82x104 and 1.32x104 particles/cm3 at US1 an US2, respectively) than at the rural one (1.15x104 particles/cm3). Canteens were the indoor microenvironment with the highest UFP (mean of 5.17x104, 3.28x104, and 4.09x104 particles/cm3 at US1, US2, and RS1), whereas the lowest concentrations were observed in classrooms (9.31x103, 11.3x103, and 7.14x103 particles/cm3 at US1, US2, and RS1). Mean indoor/outdoor ratios (I/O) of UFP at three preschools were lower than 1 (0.54–0.93), indicating that outdoor emissions significantly contributed to UFP indoors. Significant correlations were obtained between temperature, wind speed, relative humidity, solar radiation, and ambient UFP number concentrations. The estimated exposure doses were higher in children attending urban preschools; 3–5-year-old children were exposed to 4–6 times higher UFP doses than adults with similar daily schedules

Effect of a specific concurrent water and dry-land training over a season in young swimmers’ performance

The aims of this study were to assess over a full season: (i) the effect of a combined dry-land strength and conditioning and in-water program on the swimming performance of young swimmers; (ii) the effect of such program on the performance determinants; (iii) the effect of the training periodization designed. A longitudinal research design assessing an age-group of young swimmers over a season was carried out. Methods: Twenty-seven young swimmers (12 boys: 13.55±0.72-y; 15 girls: 13.16±0.93-y; both sexes in Tanner stages 2-3) were evaluated in three moments over 40 weeks. The 100-m freestyle performance, body mass, height, arm span (anthropometrics), stroke frequency, stroke length, swimming velocity, intracyclic swimming velocity (kinematics), stroke index, propelling efficiency (efficiency), squat jump, countermovement jump, and throw velocity (strength and conditioning) were assessed. A cluster analysis was computed to classify the swimmers. For the “talented” swimmers, the performance and all determinants, but the squat and countermovement jumps improved between the first and last evaluation moments. Both in-water and dry-land strength and conditioning features were responsible for the cluster discrimination in each one of the evaluation moments. All three clusters were also characterized by a mix of technical and strength & conditioning features. This highlights swimming performance as a holistic phenomenon (i.e. multiple determinants) where shifting occur in the interplay among the performance determinant according to the training periodization.info:eu-repo/semantics/publishedVersio

Longitudinal modeling in sports: young swimmers' performance and biomechanics profile

The aims was to model a latent growth curve of young swimmers' performance over a season and its relationship with biomechanics, quantify the direct effect of the exogenous variables selected on performance across a season and analyze the sex effect on the performance growth. Fourteen boys (12.33±0.65 years) and 16 girls (11.15±0.55 years) were evaluated. Performance, stroke frequency, speed fluctuation, arm's propelling efficiency, active drag, active drag coefficient and power to overcome drag were collected in four different moments of the season. Latent growth curve modeling was computed to understand the longitudinal variation of performance (endogenous variables) over the season according to the biomechanics (exogenous variables). Latent growth curve modeling showed a high inter- and intra-subject variability in the performance growth. Sex had a significant effect at the baseline and during the performance growth. In each evaluation moment, different variables had a meaningful effect on performance (M1: Da, β=-0.62; M2: Da, β=-0.53; M3: ηp, β=0.59; M4: SF, β=-0.57; all P<0.001). The models' good-of-fit was 1.40≤x2/df≤3.74 (good-reasonable). Latent modeling is a comprehensive way to gather insight about young swimmers' performance over time. Different variables were the main responsible for the performance improvement. A gender gap, intra- and inter-subject variability was verified

Relationship between thrust, anthropometrics, and dry-land strength in a national junior swimming team

Objectives: This study aimed to (i) assess an anthropometric and thrust inter-limb asymmetry, and; (ii) determine the contribution of anthropometrics, and dry-land upper-body strength and power to the thrust of talented adolescent swimmers. Methods: Eighteen talented adolescent swimmers (12 boys and 6 girls: 15.81 ± 1.62 years old) were evaluated. A set of anthropometric, dry-land upper-body strength and power, and in-water thrust were assessed. Results: Despite the fact that the dominant side presented higher values in anthropometrics (except for the hand surface area) and thrust, non-significant inter-limb differences were found. The symmetry index indicated a symmetry between upper-limbs. Hierarchical linear modeling retained as main predictors of each upper-limb thrust the respective hand surface area (dominant upper limb: estimate = 0.293, 95CI: 0.117; 0.469, p = 0.005; non-dominant upper limb: estimate = 0.295, 95CI: 0.063; 0.526, p = 0.025). The full stroke cycle retained the upper-body dry-land strength as main predictor (estimate = 0.397, 95CI: 0.189; 0.605, p = 0.002). Conclusion: The hand surface area and upper-body strength were the main predictors of each upper-limb and full stroke cycle thrust, respectively. Hence, coaches and practitioners should aim to carefully maximize the hand surface area (by finger spreading) while performing the stroke, as well as dry-land upper-body strength in order to enhance the performanceThis project was supported by the National Funds through FCT-Portuguese Foundation for Science and Technology (UID/DTP/04045/2019), and the European Fund for regional development (FEDER) allocated by the European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969). We would like also to thank the support of the University of Beira Interior and Santander Universities (Bolsa BIPD/ICIFCSH-Santander Universidades-UBI/2017).info:eu-repo/semantics/publishedVersio

The influence of anthropometric, kinematic and energetic variables and gender on swimming performance in youth athletes

The aim of this study was to assess the: (i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers’ anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1-2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1-2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance, anthropometrics, kinematics and energetics between boys and girls; (ii) swimmers with best performance are taller, have higher surface areas and better stroke mechanics; (iii) there are non-significant interactions between sports level and gender for anthropometrics, kinematics and energetics

Hydrodynamic profile of young swimmers: changes over a competitive season

The aim of this study was to analyze the changes in the hydrodynamic profile of young swimmers over a competitive season and to compare the variations according to a well-designed training periodization. Twenty-five swimmers (13 boys and 12 girls) were evaluated in (a) October (M1); (b) March (M2); and (c) June (M3). Inertial and anthropometrical measures included body mass, swimmer’s added water mass, height, and trunk transverse surface area. Swimming efficiency was estimated by the speed fluctuation, stroke index, and approximate entropy. Active drag was estimated with the velocity perturbation method and the passive drag with the gliding decay method. Hydrodynamic dimen- sionless numbers (Froude and Reynolds numbers) and hull velocity (i.e., speed at Froude number = 0.42) were also calculated. No variable presented a significant gender effect. Anthropometrics and inertial parameters plus dimensionless numbers increased over time. Swimming efficiency improved between M1 and M3. There was a trend for both passive and active drag increase from M1 to M2, but being lower at M3 than at M1. Intra-individual changes between evaluation moments suggest high between- and within-subject variations. Therefore, hydrodynamic changes over a season occur in a non-linear fashion way, where the interplay between growth and training periodization explain the unique path flow selected by each young swimmer

Experimentos em parcelas subdivididas com tratamentos primários em blocos incompletos parcialmente balanceados I: uma solução das equações normais

The objective of this study was to develop a suitable methodology for the solution of normal equations in split-plot experiments involving two-way treatment structures when the design for the whole plot experimental units is a partially balanced incomplete block design.O objetivo deste trabalho foi realizar um estudo para obtenção de uma solução adequada das equações normais de experimentos em parcelas subdivididas com tratamentos primários dispostos segundo uma estrutura de blocos incompletos parcialmente balanceados

Conception, development and validation of a software interface to assess human’s horizontal intra-cyclic velocity with a mechanical speedo-meter

The aim of this paper was to: (i) calibrate the Swimsportec® speedo-meter; (ii) concept and develop a software’s interface for it (iii) validate the full system. Calibration was done with an industrial robot. The robot arm’s performed a linear and horizontal path at a uniform movement for a set of wide range of velocities (0.5<v<4.5m/s) being the tension data acquire for each specific linear velocity. Software’s interface was developed in LabVIEW® to acquire, display and process pair wises velocity-time data on-line during the subject’s locomotion bout. To transfer data from speedo-meter to the software an acquisition card is used. System validation was done for a set of land-based human locomotion techniques (from slow walk to maximal running) in four subjects and comparing it with a Doppler radar gun. Linear regression models between speedo-meter system and radar gun where very high for both the coefficient of variation of the subject’s velocity within the full gait cycle and his maximal velocity. The 95% of interval confidence agreement limits were very close together in both variables. More than 80% of the Bland- Altman plots were with the 1.96 standard-deviation criteria used on regular basis as rule thumb for techniques validation

Occupational exposure of firefighters to polycyclic aromatic hydrocarbons in non-fire work environments

This work aims to characterize personal exposure of firefighters to polycyclic aromatic hydrocarbons (PAHs) in non-fire work environments (fire stations), and assesses the respective risks. Eighteen PAHs (16 considered by USEPA as priority pollutants, dibenzo[a,l] pyrene and benzo[j] fluoranthene) were monitored in breathing zones of workers at five Portuguese fire stations during a normal shift. The obtained levels of PAHs fulfilled all existent occupational exposure limits as well as air quality guidelines with total concentrations (Sigma PAHs) in range of 46.8-155 ng m(-3). Light compounds (2-3 rings) were the most predominant congeners (74-96% of Sigma PAHs) whereas PAHs with 5-6 rings accounted 3-9% of Sigma PAHs. Fuel and biomass combustions, vehicular traffic emissions, and use of lubricant oils were identified as the main sources of PAHs exposure at the studied fire corporations. Incremental lifetime cancer risks were below the recommend USEPA guideline of 10(-6) and thus negligible for all the studied subjects, but WHO health-based guideline level of 10(-5) was exceeded (9-44 times) at all fire corporations. These results thus show that even during non-fire situations firefighters are exposed to PAHs at levels that may promote some adverse health outcomes; therefore the respective occupational exposures to these compounds should be carefully controlled. (C) 2017This work was supported by European Union (FEDER funds through COMPETE) and National Funds (Fundação para a Ciência e Tecnologia) through projects UID/QUI/50006/2013, POCI/01/0145/FEDER/007265 and UID/EQU/00511/2013-LEPABE, by the FCT/MECwith national funds and co-funded by FEDER in the scope of the P2020 Partnership Agreement. Additional financial support was provided by Fundação para Ciência e Tecnologia through fellowships SFRH/BD/80113/2011 and SFRH/BPD/105100/2014. The authors are thankful to all firefighters involved in the study and to collaborators from Escola Superior de Saúde from Instituto Politécnico de Bragança.info:eu-repo/semantics/publishedVersio

Variability in young swimmer’ performance and its determinant factors: a two-year follow-up

Predicting sports performance and identifying talented athletes at early ages seems to be a challenging task for practioners and researchers. Based on this, the follow-up of individual pathway to exper?se should be a regular procedure among sports practioners.info:eu-repo/semantics/publishedVersio