scholarly journals Interplay of Biomechanical, Energetic, Coordinative, and Muscular Factors in a 200 m Front Crawl Swim

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Pedro Figueiredo ◽  
David R. Pendergast ◽  
João Paulo Vilas-Boas ◽  
Ricardo J. Fernandes
Keyword(s):  
Linear Regression Analysis ◽  
Muscular Activity ◽  
Multiple Linear Regression Analysis ◽  
Total Energy Expenditure ◽  
Velocity Variation ◽  
Front Crawl ◽  
Stroke Length ◽  
Task Constraints ◽  
Relative Contribution ◽  
Propelling Efficiency

This study aimed to determine the relative contribution of selected biomechanical, energetic, coordinative, and muscular factors for the 200 m front crawl and each of its four laps. Ten swimmers performed a 200 m front crawl swim, as well as 50, 100, and 150 m at the 200 m pace. Biomechanical, energetic, coordinative, and muscular factors were assessed during the 200 m swim. Multiple linear regression analysis was used to identify the weight of the factors to the performance. For each lap, the contributions to the 200 m performance were 17.6, 21.1, 18.4, and 7.6% for stroke length, 16.1, 18.7, 32.1, and 3.2% for stroke rate, 11.2, 13.2, 6.8, and 5.7% for intracycle velocity variation inx, 9.7, 7.5, 1.3, and 5.4% for intracycle velocity variation iny, 17.8, 10.5, 2.0, and 6.4% for propelling efficiency, 4.5, 5.8, 10.9, and 23.7% for total energy expenditure, 10.1, 5.1, 8.3, and 23.7% for interarm coordination, 9.0, 6.2, 8.5, and 5.5% for muscular activity amplitude, and 3.9, 11.9, 11.8, and 18.7% for muscular frequency). The relative contribution of the factors was closely related to the task constraints, especially fatigue, as the major changes occurred from the first to the last lap.

scholarly journals Perceptual Weighting of Binaural Lateralization Cues across Frequency Bands

2020 ◽  
Vol 21 (6) ◽  
pp. 485-496
Author(s):  
Axel Ahrens ◽  
Suyash Narendra Joshi ◽  
Bastian Epp
Keyword(s):  
Auditory System ◽  
Phase Locking ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Low Frequencies ◽  
Frequency Bands ◽  
Relative Contribution ◽  
Highest Weight ◽  
Auditory Enhancement ◽  
Spectral Weighting

Abstract The auditory system uses interaural time and level differences (ITD and ILD) as cues to localize and lateralize sounds. The availability of ITDs and ILDs in the auditory system is limited by neural phase-locking and by the head size, respectively. Although the frequency-specific limitations are well known, the relative contribution of ITDs and ILDs in individual frequency bands in broadband stimuli is unknown. To determine these relative contributions, or spectral weights, listeners were asked to lateralize stimuli consisting of eleven simultaneously presented 1-ERB-wide noise bands centered between 442 and 5544 Hz and separated by 1-ERB-wide gaps. Either ITDs or ILDs were varied independently across each noise band, while fixing the other interaural disparity to either 0 dB or 0 μs. The weights were obtained using a multiple linear regression analysis. In a second experiment, the effect of auditory enhancement on the spectral weights was investigated. The enhancement of single noise bands was realized by presenting ten of the noise bands as preceding and following sounds (pre- and post-cursors, respectively). Listeners were asked to lateralize the stimuli as in the first experiment. Results show that in the absence of pre- and post-cursors, only the lowest or highest frequency band received highest weight for ITD and ILD, respectively. Auditory enhancement led to significantly enhanced weights given to the band without the pre- and post-cursor. The weight enhancement could only be observed at low frequencies, when determined with ITD cues and for low and high frequencies for ILDs. Hence, the auditory system seems to be able to change the spectral weighting of binaural information depending on the information content.

scholarly journals Cross-cultural determinants of pre-adolescent self-esteem and body image

2017 ◽  
Vol 4 (8) ◽  
pp. 2767
Author(s):  
Manuel De Gracia ◽  
Patricia Trujano ◽  
Carlos Nava ◽  
Gilberto Limón
Keyword(s):  
Body Image ◽  
Linear Regression Analysis ◽  
Body Esteem ◽  
Multiple Linear Regression Analysis ◽  
Self Esteem ◽  
Eating Attitudes ◽  
Cross Cultural ◽  
Subjective Perception ◽  
Relative Contribution ◽  
And Behaviors

Background: The general framework of this research is that the sociocultural context and socio-economic conditions in different countries representing the macro-system of the transactional model of health, with varying degrees of cultural and linguistic familiarity and contact history. Culturally bound definitions of what is desirable and attractive play an important role in body image formation.Methods: The aim of this cross-cultural study was to evaluate the different effects of general self-esteem, eating attitudes and behaviors, and the subjective perception of body image in two representative samplings of urban pre-adolescents (9-12 years old). All the participants were given the following tests: LAWSEQ, ChEAT-26, CFD, and BEStudy.Results: The multiple linear regression analysis showed the relative contribution of each independent variable: the LAWSEQ score explained 12.8% of the variance of the BES score, followed by the BMI (9.3%), the ChEAT-26 score (9.1%), and the CFD (7.8%). The results showed a differential profile between the two samplings.Conclusions: General self-esteem was the strongest predictive variable associated with higher levels of body esteem, while habits and behaviors related to worry about food and the choice of a thinner body image ideal were predictive of lower body esteem, regardless of the nationality, sex, or age of the participants. 

scholarly journals Kinematic Variables of Disabled Swimmers and Their Correlation With the International Paralympic Committee Classification

Motor Control ◽  
2021 ◽  
pp. 1-12
Author(s):  
Karini Borges dos Santos ◽  
Paulo Cesar Barauce Bento ◽  
Carl Payton ◽  
André Luiz Felix Rodacki
Keyword(s):  
Velocity Variation ◽  
Swimming Velocity ◽  
Stroke Rate ◽  
Functional Classification ◽  
Crucial Point ◽  
Front Crawl ◽  
Stroke Length ◽  
Underwater Cameras ◽  
Current Classification ◽  
Phase Coordination

This study described the kinematic variables of disabled swimmers’ performance and correlated them with their functional classification. Twenty-one impaired swimmers (S5–S10) performed 50-m maximum front-crawl swimming while being recorded by four underwater cameras. Swimming velocity, stroke rate, stroke length, intracycle velocity variation, stroke dimensions, hand velocity, and coordination index were analyzed. Kendall rank was used to correlate stroke parameters and functional classification with p < .05. Swimming velocity, stroke length, and submerged phase were positively correlated with the para swimmers functional classification (.61, .50, and .41; p < .05, respectively), while stroke rate, velocity hand for each phase, coordination index, and intracyclic velocity variation were not (τ between −.11 and .45; p > .05). Thus, some objective kinematic variables of the impaired swimmers help to support current classification. Improving hand velocity seems to be a crucial point to be improved among disabled swimmers.

scholarly journals Energetic and Biomechanical Contributions for Longitudinal Performance in Master Swimmers

2020 ◽  
Vol 5 (2) ◽  
pp. 37
Author(s):  
Daniel A. Marinho ◽  
Maria I. Ferreira ◽  
Tiago M. Barbosa ◽  
José Vilaça-Alves ◽  
Mário J. Costa ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Swimming Performance ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Stroke Index ◽  
Front Crawl ◽  
Stroke Length ◽  
Propelling Efficiency ◽  
Peak Blood ◽  
Peak Blood Lactate

Background: The current study aimed to verify the changes in performance, physiological and biomechanical variables throughout a season in master swimmers. Methods: Twenty-three master swimmers (34.9 ± 7.4 years) were assessed three times during a season (December: M1, March: M2, June: M3), in indoor 25 m swimming pools. An incremental 5 × 200 m test was used to evaluate the speed at 4 mmol·L−1 of blood lactate concentration (sLT), maximal oxygen uptake (VO2max), peak blood lactate ([La-]peak) after the test, stroke frequency (SF), stroke length (SL), stroke index (SI) and propelling efficiency (ηp). The performance was assessed in the 200 m front crawl during competition. Results: Swimming performance improved between M1, M2 (2%, p = 0.03), and M3 (4%, p < 0.001). Both sLT and VO2max increased throughout the season (4% and 18%, p < 0.001, respectively) but not [La-]peak. While SF decreased 5%, SL, SI and ηp increased 5%, 7%, and 6% (p < 0.001) from M1 to M3. Conclusions: Master swimmers improved significantly in their 200 m front crawl performance over a season, with decreased SF, and increased SL, ηp and SI. Despite the improvement in energetic variables, the change in performance seemed to be more dependent on technical than energetic factors.

The Effect of Intensity on 3-Dimensional Kinematics and Coordination in Front-Crawl Swimming

2016 ◽  
Vol 11 (6) ◽  
pp. 768-775 ◽  
Author(s):  
Kelly de Jesus ◽  
Ross Sanders ◽  
Karla de Jesus ◽  
João Ribeiro ◽  
Pedro Figueiredo ◽  
...  
Keyword(s):  
Lactate Concentration ◽  
Interlimb Coordination ◽  
3D Analysis ◽  
Front Crawl ◽  
Stroke Length ◽  
Task Constraints ◽  
Competitive Swimming ◽  
3 Dimensional ◽  
Wide Range ◽  
Curve Modeling

Background:Coaches are often challenged to optimize swimmers’ technique at different training and competition intensities, but 3-dimensional (3D) analysis has not been conducted for a wide range of training zones.Purpose:To analyze front-crawl 3D kinematics and interlimb coordination from low to severe swimming intensities.Methods:Ten male swimmers performed a 200-m front crawl at 7 incrementally increasing paces until exhaustion (0.05-m/s increments and 30-s intervals), with images from 2 cycles in each step (at the 25- and 175-m laps) being recorded by 2 surface and 4 underwater video cameras. Metabolic anaerobic threshold (AnT) was also assessed using the lactate-concentration–velocity curve-modeling method.Results:Stroke frequency increased, stroke length decreased, hand and foot speed increased, and the index of interlimb coordination increased (within a catch-up mode) from low to severe intensities (P ≤ .05) and within the 200-m steps performed above the AnT (at or closer to the 4th step; P ≤ .05). Concurrently, intracyclic velocity variations and propelling efficiency remained similar between and within swimming intensities (P > .05).Conclusions:Swimming intensity has a significant impact on swimmers’ segmental kinematics and interlimb coordination, with modifications being more evident after the point when AnT is reached. As competitive swimming events are conducted at high intensities (in which anaerobic metabolism becomes more prevalent), coaches should implement specific training series that lead swimmers to adapt their technique to the task constraints that exist in nonhomeostatic race conditions.

The Effects of Leg Kick on Swimming Speed and Arm-Stroke Efficiency in the Front Crawl

2017 ◽  
Vol 12 (6) ◽  
pp. 728-735 ◽  
Author(s):  
Ricardo Peterson Silveira ◽  
Flávio Antônio de Souza Castro ◽  
Pedro Figueiredo ◽  
João Paulo Vilas-Boas ◽  
Paola Zamparo
Keyword(s):  
Swimming Speed ◽  
Polynomial Regression ◽  
Swimming Pool ◽  
Forward Speed ◽  
Front Crawl ◽  
Stroke Length ◽  
Stroke Frequency ◽  
Relative Contribution ◽  
Percentage Difference ◽  
Order Polynomial

Purpose:To analyze the effects of swimming pace on the relative contribution of leg kick to swimming speed and to compare arm-stroke efficiency (ηF) assessed when swimming with the arms only (SAO) and while swimming front crawl (FCS) using individual and fixed adjustments to arm-stroke and leg-kick contribution to forward speed.Methods:Twenty-nine master swimmers (21 men, 8 women) performed SAO and FCS at 6 self-selected speeds from very slow to maximal. The average swimming speed (v), stroke frequency (SF), and stroke length (SL) were assessed in the central 10 m of the swimming pool. Then, a 2nd-order polynomial regression was used to obtain values of v at paired SF. The percentage difference in v between FCS and SAO, for each paired SF, was used to calculate the relative contributions of the arm stroke (AC) and leg kick (LC) to FCS. Then ηF was calculated using the indirect “paddle-wheel” approach in 3 different ways: using general, individual, and no adjustments to AC.Results:The LC increased with SF (and speed) from –1% ± 4% to 11% ± 1% (P < .05). At the lower FCS speeds, ηF calculated using general adjustments was lower than ηF calculated using individual adjustments (P < .05), but differences disappear at the fastest speeds. Finally, ηF calculated using individual adjustments to LC in the FCS condition did not differ with ηF assessed in the SAO condition at all the investigated speeds.Conclusions:The relative contributions of the arm stroke and leg kick should be individually estimated to reduce errors when calculating arm-stroke efficiency at different speeds and in different swimmers.

scholarly journals Perceptual weighting of binaural lateralization cues across frequency bands

2019 ◽  
Author(s):  
Axel Ahrens ◽  
Suyash Narendra Joshi ◽  
Bastian Epp
Keyword(s):  
Auditory System ◽  
Phase Locking ◽  
Linear Regression Analysis ◽  
Broad Band ◽  
Multiple Linear Regression Analysis ◽  
Temporal Context ◽  
Low Frequencies ◽  
Frequency Bands ◽  
Relative Contribution ◽  
Spectral Weighting

AbstractThe auditory system uses interaural time- and level differences (ITD and ILD) as cues to localize and lateralize sounds. The availability of ITDs and ILDs in the auditory system is limited by neural phase-locking and by the head size, respectively. Although the frequency-specific limitations are well known, the relative contribution of ITDs and ILDs in individual frequency bands in broad-band stimuli are unknown. To determine these relative contributions, or spectral weights, listeners were asked to judge the lateralization of stimuli consisting of eleven simultaneously presented 1-ERB-wide noise bands centered between 442 Hz and 5544 Hz and separated by 1-ERB-wide gaps. Interaural disparities were applied to each noise band and were roved independently on every trial. The weights were obtained using a multiple linear regression analysis. In a second experiment the effect of temporal context on the spectral weights was investigated. Ten of the noise bands were used as pre- and postcursors and listeners were asked to lateralize the stimuli. Results show that only the lowest- or highest frequency band received highest weight for ITD and ILD, respectively. Temporal context led to significantly enhanced weights given to the band without the pre- and postcursor. The weight enhancement could only be observed at low frequencies, when determined with ITD cues and for low and high frequencies for ILDs. Hence, the auditory system seems to be able to change the spectral weighting of binaural information depending on the information content.PACS43.64.-q · 43.64.+r · 87.19.lt · 43.66.-x · 43.66.+y · 43.64.Bt

scholarly journals Analyzing Japanese University English Teachers’ Self-Efficacy to Teach Online

2021 ◽  
Vol 2020 (1) ◽  
pp. 81
Author(s):  
Nancy Shzh-chen Lee ◽  
Chie Ogawa
Keyword(s):  
Self Efficacy ◽  
Online Teaching ◽  
Linear Regression Analysis ◽  
English Teachers ◽  
Multiple Linear Regression Analysis ◽  
Teaching Online ◽  
Face To Face ◽  
Relative Contribution ◽  
Integration Of Technology ◽  
Time Usage

The 2020 Covid-19 pandemic changed the delivery of many classes from face-to-face to online. This study was an attempt to investigate online English teaching self-efficacy by surveying 138 university English teachers in Japan during the pandemic. A survey with 30 Likert-scale items was developed to examine four latent constructs of online teaching self-efficacy: pedagogy, technology, communicative language teaching (CLT), and self-management. In addition, how these constructs correlated with each other as well as the relative contribution of the participants’ background variables and questionnaire subscales to overall self-efficacy were examined. Results showed that teachers were highly self-efficacious about teaching online especially with the integration of technology but were not self-efficacious to manage themselves online especially with time usage. In addition, multiple linear regression analysis showed that the four constructs predicted the participants’ overall self-efficacy, but their background variables did not impact their overall self-efficacy to teach online. 2020年Covid-19パンデミックで多くの授業が対面からオンラインに切り替わった。本研究では、日本の138名の大学英語教員へのアンケート調査によるオンライン授業に対する自己効力感を調査した。30項目のリッカート尺度を用いた質問項目では、自己効力感の四つの潜在的構成要素（教授法、テクノロジー、コミュニカティブ・ランゲージティーチング、自己管理）を調べた。加えて、これらの構成要素間の相関関係を調べ、さらに潜在構成要素と教員層データがオンライン授業全体に対する自己効力感にどの程度影響するのか分析を行った。結果、英語教員はオンライン授業に対しての自己効力感が高いことが明らかになった。教員がテクノロジーに対して高い自己効力感を持ったものの、自己管理、特に時間の利用に対しては自己効力感が低かった。また回帰分析では、四つの構成要素は英語教員の全体的な自己効力感を説明するが、教員層データは影響を及ぼさないことがわかった。

Biophysical Determinants of Front-Crawl Swimming at Moderate and Severe Intensities

2017 ◽  
Vol 12 (2) ◽  
pp. 241-246 ◽  
Author(s):  
João Ribeiro ◽  
Argyris G. Toubekis ◽  
Pedro Figueiredo ◽  
Kelly de Jesus ◽  
Huub M. Toussaint ◽  
...  
Keyword(s):  
Metabolic Power ◽  
Improve Performance ◽  
Front Crawl ◽  
Stroke Length ◽  
Factors Associated ◽  
Biophysical Analysis ◽  
Propelling Efficiency ◽  
Biomechanical Parameters ◽  
And Performance ◽  
High Level

Purpose:To conduct a biophysical analysis of the factors associated with front-crawl performance at moderate and severe swimming intensities, represented by anaerobic-threshold (vAnT) and maximal-oxygen-uptake (vV̇O2max) velocities.Methods:Ten high-level swimmers performed 2 intermittent incremental tests of 7 × 200 and 12 × 25 m (through a system of underwater push-off pads) to assess vAnT, and vV̇O2max, and power output. The 1st protocol was videotaped (3D reconstruction) for kinematic analysis to assess stroke frequency (SF), stroke length (SL), propelling efficiency (ηP), and index of coordination (IdC). V̇O2 was measured and capillary blood samples (lactate concentrations) were collected, enabling computation of metabolic power. The 2nd protocol allowed calculating mechanical power and performance efficiency from the ratio of mechanical to metabolic power.Results:Neither vAnT nor vV̇O2max was explained by SF (0.56 ± 0.06 vs 0.68 ± 0.06 Hz), SL (2.29 ± 0.21 vs 2.06 ± 0.20 m), ηP (0.38 ± 0.02 vs 0.36± 0.03), IdC (–12.14 ± 5.24 vs –9.61 ± 5.49), or metabolic-power (1063.00 ± 122.90 vs 1338.18 ± 127.40 W) variability. vV̇O2max was explained by power to overcome drag (r = .77, P ≤ .05) and ηP (r = .72, P ≤ .05), in contrast with the nonassociation between these parameters and vAnT; both velocities were well related (r = .62, P ≤ .05).Conclusions:The biomechanical parameters, coordination, and metabolic power seemed not to be performance discriminative at either intensity. However, the increase in power to overcome drag, for the less metabolic input, should be the focus of any intervention that aims to improve performance at severe swimming intensity. This is also true for moderate intensities, as vAnT and vV˙O2max are proportional to each other.

Pengaruh Motivasi Kerja Dan Lingkungan Kerja Terhadap Kinerja Karyawan Bappeda Kabupaten Wonosobo Tahun 2013

2017 ◽  
Vol 1 (2) ◽  
pp. 135-147
Author(s):  
Ary Sutrischastini ◽  
Ratna Setyani
Keyword(s):  
Work Environment ◽  
Work Motivation ◽  
Employee Performance ◽  
Linear Regression Analysis ◽  
Test Validity ◽  
Multiple Linear Regression Analysis ◽  
Reliability Testing ◽  
Evaluation Influence ◽  
Environment Variables ◽  
Research Goal

This research goal is to identification and evaluation influence of work motivation and work environment to employee’s performance in BAPPEDA Kabupaten Wonosobo. The object of this research is 37 employees of Badan Perencanaan Pembangunan Kabupaten Wonosobo. And the location of this research is at Badan Perencanaan Pembangunan Kabupaten Wonosobo. The analysis used is test validity, reliability testing, and test the hypothesis, with the help of the computer program SPSS version 17, using multiple linear regression analysis. Based on calculations of data and analysis used, the regression equation is obtained: Y = 11.733 + 0.320 X1 +0.334 X2 + ε, by using the equation regression analytical method can conclude that (X1) take effect positively against employees performance. With t value in amount of 2,219 (bigger than t in table in amount of 1,690) and significance value in amount of 0,33. By applying significance limited value in amount of 0,05, it means, hypothesis that claim if work motivation take effect against employees performance can be accepted. There is a positive and significant correlation between work environment variables (X2) against employees. With t value in amount of 2,219 (bigger than t in table in amount of 1,690) and significance value in amount of 0,33 (smaller than 0,5). Simultaneously, work motivation take effect positively and significantly against employees performance with the F value in amount of 11,562 (bigger than 0.05), then obtained significance value 0.000. It can be concluded that the work motivation and work environment has a positive and significant influence on employee performance in BAPPEDA Kabupaten Wonosobo.

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