scholarly journals Modeling the Links Between Young Swimmers’ Performance: Energetic and Biomechanic Profiles

2010 ◽  
Vol 22 (3) ◽  
pp. 379-391 ◽  
Author(s):  
Tiago M. Barbosa ◽  
Mário Costa ◽  
Daniel A. Marinho ◽  
Joel Coelho ◽  
Marc Moreira ◽  
...  
Keyword(s):  
Structural Equation ◽  
Swimming Performance ◽  
Flow Analysis ◽  
Equation Modeling ◽  
Swimming Velocity ◽  
Stroke Index ◽  
Analysis Model ◽  
Stroke Length ◽  
Propulsive Efficiency ◽  
Biomechanical Assessment

The aim was to develop a path-flow analysis model for young swimmers’ performance based on biomechanical and energetic parameters, using structural equation modeling. Thirty-eight male young swimmers served as subjects. Performance was assessed by the 200-m freestyle event. For biomechanical assessment the stroke length, the stroke frequency and the swimming velocity were analyzed. Energetics assessment included the critical velocity, the stroke index and the propulsive efficiency. The confirmatory model explained 79% of swimming performance after deleting the stroke index-performance path, which was nonsignificant (SRMR = 0.06). As a conclusion, the model is appropriate to explain performance in young swimmers.

scholarly journals The Influence of Anthropometric, Kinematic and Energetic Variables and Gender on Swimming Performance in Youth Athletes

2013 ◽  
Vol 39 (1) ◽  
pp. 203-211 ◽  
Author(s):  
Jorge E Morais ◽  
Nuno D Garrido ◽  
Mário C Marques ◽  
António J Silva ◽  
Daniel A Marinho ◽  
...  
Keyword(s):  
Surface Area ◽  
Swimming Performance ◽  
Gender Effect ◽  
Swimming Velocity ◽  
Stroke Index ◽  
Propulsive Efficiency ◽  
Stroke Frequency ◽  
Self Evaluation ◽  
Speed Fluctuation ◽  
And Gender

Abstract 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.

Spatial-temporal variables for swimming coaches: A comparison study between video and TritonWear sensor

2021 ◽  
pp. 174795412110137
Author(s):  
Robin Pla ◽  
Thibaut Ledanois ◽  
Escobar David Simbana ◽  
Anaël Aubry ◽  
Benjamin Tranchard ◽  
...  
Keyword(s):  
Swimming Performance ◽  
Video Recording ◽  
Open Water ◽  
Percentage Error ◽  
Stroke Index ◽  
Wearable Sensor ◽  
Stroke Length ◽  
Video Recordings ◽  
Temporal Variables ◽  
Training Sets

The main aim of this study was to evaluate the validity and the reliability of a swimming sensor to assess swimming performance and spatial-temporal variables. Six international male open-water swimmers completed a protocol which consisted of two training sets: a 6×100m individual medley and a continuous 800 m set in freestyle. Swimmers were equipped with a wearable sensor, the TritonWear to collect automatically spatial-temporal variables: speed, lap time, stroke count (SC), stroke length (SL), stroke rate (SR), and stroke index (SI). Video recordings were added as a “gold-standard” and used to assess the validity and the reliability of the TritonWear sensor. The results show that the sensor provides accurate results in comparison with video recording measurements. A very high accuracy was observed for lap time with a mean absolute percentage error (MAPE) under 5% for each stroke (2.2, 3.2, 3.4, 4.1% for butterfly, backstroke, breaststroke and freestyle respectively) but high error ranges indicate a dependence on swimming technique. Stroke count accuracy was higher for symmetric strokes than for alternate strokes (MAPE: 0, 2.4, 7.1 & 4.9% for butterfly, breaststroke, backstroke & freestyle respectively). The other variables (SL, SR & SI) derived from the SC and the lap time also show good accuracy in all strokes. The wearable sensor provides an accurate real time feedback of spatial-temporal variables in six international open-water swimmers during classical training sets (at low to moderate intensities), which could be a useful tool for coaches, allowing them to monitor training load with no effort.

scholarly journals Research for Risk Management of Construction Projects in Taiwan

2021 ◽  
Vol 13 (4) ◽  
pp. 2034
Author(s):  
Chien-Liang Lin ◽  
Bey-Kun Chen
Keyword(s):  
Risk Management ◽  
Risk Analysis ◽  
Structural Equation ◽  
Construction Projects ◽  
Construction Project ◽  
Equation Modeling ◽  
Analysis Model ◽  
Sustainable Operation ◽  
Management Procedure ◽  
Risk Managers

Risks inevitably exist in all stages of a project. In a construction project, which is highly dynamic and complex, risk factors affect the expected achievement rates of the three main performance goals, namely schedule, cost, and quality. A comprehensive risk management procedure requires three crucial steps: risk confirmation, analysis, and treatment. Risk analysis is the core of risk management. Through structural equation modeling, this study developed a risk analysis model that takes a different perspective and considered the occurrence probability of risk events and the extent to which these events affect a project. The contractor dimension was discovered to exert the strongest influence on an overall project, followed by the subcontractor and design dimensions. This paper proposes a novel construction project risk analysis model, which considers the entire project. The proposed model can be used as a reference for risk managers to make decisions about project risks, so as to achieve the ultimate goal of saving resources and the sustainable operation of the construction project.

scholarly journals Wave Characteristics in Breaststroke Technique with and Without Snorkel Use

2013 ◽  
Vol 39 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Ana Conceição ◽  
António J. Silva ◽  
José Boaventura ◽  
Daniel A. Marinho ◽  
Hugo Louro
Keyword(s):  
Normal Condition ◽  
Mass Velocity ◽  
Second Harmonic ◽  
Harmonic Wave ◽  
The Body ◽  
Swimming Velocity ◽  
Stroke Index ◽  
Stroke Length ◽  
Wave Characteristics ◽  
Second Wave

Abstract The purpose of this paper was to examine the characteristics of waves generated when swimming with and without the use of Aquatrainer® snorkels. Eight male swimmers performed two maximal bouts of 25 m breaststroke, first without the use of a snorkel (normal condition) and then using a snorkel (snorkel condition). The body landmarks, centre of the mass velocity, stroke rate, stroke length, stroke index, and Strouhal number (St) were quantified. Fourier analysis was conducted to determine the frequency, amplitude, and phase characteristics of the vertical undulations. We also determined the undulation period, the first and second harmonic wave percentage, and the contribution of these components to the power of each of the wave signals. The first wave harmonics had a frequency of 0.76 Hz (normal condition) and 0.78 Hz (snorkel condition), and the second wave harmonics had a frequency of 1.52 Hz (normal condition) and 1.56 Hz (snorkel condition). Under the normal conditions, the wave amplitude was higher on the vertex (0.72 m) and cervical (0.32 m) than that produced under snorkel conditions (0.71 m and 0.28 m, respectively). The lowest values were found in the hip (0.03 m in normal conditions, and 0.02 m in snorkel conditions) and in the trunk (0.06 m in normal conditions, and 0.04 m in snorkel conditions). It can be concluded that snorkel use seems to lead to slight changes in the biomechanical pattern in swimming velocity, as well as several stroke mechanical variables.

scholarly journals How Informative are the Vertical Buoyancy and the Prone Gliding Tests to Assess Young Swimmers' Hydrostatic and Hydrodynamic Profiles?

2012 ◽  
Vol 32 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Tiago Barbosa ◽  
Mário Costa ◽  
Jorge Morais ◽  
Marc Moreira ◽  
António Silva ◽  
...  
Keyword(s):  
Body Mass ◽  
Fat Mass ◽  
Flow Model ◽  
Flow Analysis ◽  
Young Male ◽  
The Body ◽  
Mean Square ◽  
Analysis Model ◽  
Stroke Length ◽  
Stroke Frequency

How Informative are the Vertical Buoyancy and the Prone Gliding Tests to Assess Young Swimmers' Hydrostatic and Hydrodynamic Profiles? The aim of this research was to develop a path-flow analysis model to highlight the relationships between buoyancy and prone gliding tests and some selected anthropometrical and biomechanical variables. Thirty-eight young male swimmers (12.97 ± 1.05 years old) with several competitive levels were evaluated. It were assessed the body mass, height, fat mass, body surface area, vertical buoyancy, prone gliding after wall push-off, stroke length, stroke frequency and velocity after a maximal 25 [m] swim. The confirmatory model included the body mass, height, fat mass, prone gliding test, stroke length, stroke frequency and velocity. All theoretical paths were verified except for the vertical buoyancy test that did not present any relationship with anthropometrical and biomechanical variables nor with the prone gliding test. The good-of-fit from the confirmatory path-flow model, assessed with the standardized root mean square residuals (SRMR), is considered as being close to the cut-off value, but even so not suitable of the theory (SRMR = 0.11). As a conclusion, vertical buoyancy and prone gliding tests are not the best techniques to assess the swimmer's hydrostatic and hydrodynamic profile, respectively.

scholarly journals Biomechanical characterization of swimmers with physical disabilities

Motricidade ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 103-112 ◽  
Author(s):  
Valdir Junior ◽  
Alexandre Medeiros ◽  
Kelly Jesus ◽  
Nuno Domingos Garrido ◽  
Rui Corredeira ◽  
...  
Keyword(s):  
Swimming Performance ◽  
Velocity Variation ◽  
Swimming Velocity ◽  
Stroke Length ◽  
Stroke Frequency ◽  
Mean Values ◽  
Functional Classes ◽  
The Mean ◽  
Incremental Protocol

The evaluation of swimming technique is one of the main aspects to be considered in any training program, with biomechanics being an important source of knowledge. It was our objective to characterize the biomechanical parameters (SL and SF) relating them to the swimming velocity (v) at different intensities and to analyze within each swimming stroke cycle the intra-cyclic velocity variation (IVV) in a group of motor disabled swimmers. Eight disabled male swimmers (25.83 ± 2.93 years old, 72.45 ± 9.26 kg body mass and 1.79 ± 0.11 m of height) of the following functional classes: S6 (n = 1), S8 (n = 2) and S9 (n = 5) participated in this study. Swimmers were evaluated in the kinematic parameters v, stroke frequency (SF) and stroke length (SL) along with an incremental protocol of 6 x 200 m in the the crawl stroke. Data were registered in each step at the distances of 100 and 175 m. With increasing velocity, the mean values of SL decreased while the mean values of SF increased. To achieve higher swimming velocities, swimmers compensated the lack of the propulsive segment increasing SF to increase swimming speed. For the mean values of IVV at 100m distance, a decrease between the first and second levels, followed by a tendency to stabilize from the 2nd to the 6th level is presented. For the 175 m distance, there was a decrease in IVV with an increase in swimming velocity. Stroke frequency is directly related to the magnitude of IVV, which directly influences swimming performance.

scholarly journals Time to Exhaustion at the VO2max Velocity in Swimming: A Review

2012 ◽  
Vol 32 (1) ◽  
pp. 121-134 ◽  
Author(s):  
Ricardo Fernandes ◽  
J. Vilas-Boas
Keyword(s):  
Anaerobic Threshold ◽  
Direct Relationship ◽  
Aerobic Power ◽  
Slow Component ◽  
Lactate Production ◽  
Inverse Correlation ◽  
Time To Exhaustion ◽  
Swimming Velocity ◽  
Stroke Index ◽  
Stroke Length

Time to Exhaustion at the VO2max Velocity in Swimming: A Review The aim of this study was to present a review on the time to exhaustion at the minimum swimming velocity corresponding to maximal oxygen consumption (TLim-vVO2max). This parameter is critical both for the aerobic power and the lactate tolerance bioenergetical training intensity zones, being fundamental to characterize it, and to point out its main determinants. The few number of studies conducted in this topic observed that swimmers were able to maintain an exercise intensity corresponding to maximal aerobic power during 215 to 260 s (elite swimmers), 230 to 260 s (high level swimmers) and 310 to 325 s (low level swimmers), and no differences between genders were reported. TLim-vVO2max main bioenergetic and functional determinants were swimming economy and VO2 slow component (direct relationship), and vVO2max, velocity at anaerobic threshold and blood lactate production (inverse relationship); when more homogeneous groups of swimmers were analysed, the inverse correlation value between TLim-vVO2max and vVO2max was not so evident. In general, TLim-vVO2max was not related to VO2max. TLim-vVO2max seems also to be influenced by stroking parameters, with a direct relationship to stroke length and stroke index, and an inverse correlation with stroke rate. Assessing TLim-vVO2max, together with the anaerobic threshold and the biomechanical general parameters, will allow a larger spectrum of testing protocols application, helping to build more objective and efficient training programs.

Antecedents of attitudes toward eWOM communication: differences across channels

2016 ◽  
Vol 26 (5) ◽  
pp. 1030-1051 ◽  
Author(s):  
Yaniv Gvili ◽  
Shalom Levy
Keyword(s):  
Structural Equation ◽  
Equation Modeling ◽  
Future Research ◽  
Analysis Model ◽  
Content Type ◽  
Attitudinal Differences ◽  
Web Forums ◽  
Communication Differences ◽  
Media Channels ◽  
Digital Channels

Purpose Despite the extensive academic interest in electronic word of mouth (eWOM) communication, consumer attitudes toward eWOM communication have been neglected. The purpose of this paper is to propose a conceptual framework for attitudes toward eWOM communication across digital channels. Design/methodology/approach Data were collected through a web-based survey on seven major digital communication channels. ANOVA was applied in order to analyze their differences. In addition, structural equation modeling was used to test the eWOM attitude model, using a sample of 864 participants who have had prior experience with the channels under study. Findings Findings indicate that both attitude toward eWOM and its antecedents significantly differ across channels. Additionally, a path analysis model reveals that the original integrated model applies to eWOM communications. Yet, in the case of eWOM, irritating messages may be positively related to attitude toward the channel, and credibility serves as a mediator of message value. Research limitations/implications This paper supports the notion that attitude toward eWOM communication significantly differs across media channels. Future research should examine additional implications of attitude toward eWOM, and explore new and evolving channels. Practical implications Practitioners should adjust their eWOM media strategy to their objectives; blogs and social networks are more effective for brand attitude formation, whereas web forums enhance message credibility. Originality/value To the best of the authors’ knowledge, this is the first research study that tests attitudinal differences toward eWOM across digital channels. As such, it contributes to the understanding of people’s perception of these platforms.

Linking Selected Kinematic, Anthropometric and Hydrodynamic Variables to Young Swimmer Performance

2012 ◽  
Vol 24 (4) ◽  
pp. 649-664 ◽  
Author(s):  
Jorge E. Morais ◽  
Sérgio Jesus ◽  
Vasco Lopes ◽  
Nuno Garrido ◽  
António Silva ◽  
...  
Keyword(s):  
Surface Area ◽  
Structural Equation ◽  
Goodness Of Fit ◽  
Swimming Performance ◽  
Equation Model ◽  
Technical Training ◽  
Stroke Index ◽  
Arm Span ◽  
Swimming Efficiency ◽  
Speed Fluctuation

The aim of this study was to develop a structural equation model (i.e., a confirmatory technique that analyzes relationships among observed variables) for young swimmer performance based on selected kinematic, anthropometric and hydrodynamic variables. A total of 114 subjects (73 boys and 41 girls of mean age of 12.31 ± 1.09 years; 47.91 ± 10.81 kg body mass; 156.57 ± 10.90 cm height and Tanner stages 1–2) were evaluated. The variables assessed were the: (i) 100 [m] freestyle performance; (ii) stroke index; (iii) speed fluctuation; (iv) stroke distance; (v) active drag; (vi) arm span and; (vii) hand surface area. All paths were significant (p < .05). However, in deleting the path between the hand surface area and the stroke index, the model goodness-of-fit significantly improved. Swimming performance in young swimmers appeared to be dependent on swimming efficiency (i.e., stroke index), which is determined by the remaining variables assessed, except for the hand surface area. Therefore, young swimmer coaches and practitioners should design training programs with a focus on technical training enhancement (i.e., improving swimming efficiency).

scholarly journals The influence of different hand paddle size on 100-m front crawl kinematics

2012 ◽  
Vol 34 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Daniel López-Plaza ◽  
Fernando Alacid ◽  
Pedro A. López-Miñarro ◽  
José M. Muyor
Keyword(s):  
Swimming Performance ◽  
Video Camera ◽  
Swimming Velocity ◽  
Stroke Rate ◽  
Front Crawl ◽  
Stroke Length ◽  
Elite Swimmers ◽  
The Mean

AbstractThe purpose of this study was to determine the influence of different sizes of hand paddles on kinematicparameters during a 100 m freestyle swimming performance in elite swimmers. Nine elite swimmers (19.1 ± 1.9 years)completed three tests of 100 m without paddles, with small paddles (271.27 cm2) and with large paddles (332.67 cm2),respectively. One video camera was used to record the performance during the three trials. The mean swimmingvelocity, stroke rate and stroke length were measured in the central 10 meters of each 50 m length. The results showedthat stroke length tended to increase significantly when wearing hand paddles (p < 0.05) during both the first andsecond 50 m sections whereas the increase in swimming velocity occurred only in the second 50 m (p < 0.05).Conversely, the stroke rate showed a slight decreasing trend with increasing paddle size. During the 100 m freestyletrial the stroke kinematics were changed significantly as a result of the increase in propelling surface size when handpaddles were worn.

Sign in / Sign up

Export Citation Format

Share Document