scholarly journals Effect of Additional Buoyancy Swimsuits on Performance of Competitive Swimmers

2021 ◽  
Vol 14 (1) ◽  
pp. 98-105
Author(s):  
Shin-Ichiro Moriyama ◽  
Yasunori Watanabe ◽  
Tsubasa Kurono ◽  
Jorge E. Morais ◽  
Daniel A. Marinho ◽  
...  

Background: When in water, the Centers of Buoyancy (CoB) and Mass (CoM) of the human body are positioned cranially and caudally, respectively. With increasing distance between these centers, the sinking torque of the lower limbs increases, with a subsequent decrease in swimming performance due to increased drag. Objective: To clarify the effect of additional buoyancy swimsuits on swimming performance. Methods: The subjects were eight competitive male swimmers of mean ±SD age 21±2 years. Swimming performance was compared between Conventional (CS) and Additional Buoyancy Swimsuits (ABS). CoM and CoB were identified on land and in water, respectively, with the swimmers maintaining a horizontal posture. CoM was measured by the reaction board method. CoB was calculated as the force exerted in the vertical direction accompanied by changes in inspiratory volume. Swimming velocity and Blood Lactate (BL) concentration value during 200 m front crawl in trials at four different speeds (curve test) were recorded as swimming performance. Results: No significant difference in inspiratory volume was observed between CS and ABS (small effect size, d=0.28). The distance between CoM and CoB was significantly shorter for CS than ABS (p < 0.001; large effect size, d=1.08). Both swimming velocity at BL of 4 mmol·L-1 and maximal effort were significantly faster for ABS (p < 0.042; 0.008), with large effect size (d=0.91; 0.98). However, there was no significant difference in maximal BL between CS and ABS (small effect size, d=0.37). Conclusion: ABS improves swimming performance by streamlining the horizontal posture.

Author(s):  
سيد طنطاوي

The aim of this research is to develop some concepts of web3 for the education technology specialist, to present a proposed training program for web3 technology, to define the concepts and technology of web3. There is a statistically significant difference at the level (0.05) between the average scores of education technology specialists in the pre and post applications to test the web3.0 concepts in favor of the post application. In light of the significance of the differences using the "T" tests, the square of ETA (2η) was calculated using the equation Eta square (2 η) to find the magnitude of the effect of the independent variable (training program) in the dependent variable (development of web3.0 concepts), and by calculating the value of the square of ETA (2)) (Al-Amiri, 2006, 233), reached (0.98), which indicates that the training program has a significant impact on the acquisition of some concepts of web3.0, where this value shows that the training program contributed (98%) of the total variance In developing these concepts,It is a large percentage indicating the effectiveness of the training program in developing web3.0 concepts for the target research sample, which is the education technology specialist (if the effect size = 0.2 is the effect is weak, and if the impact size = 0.5, the effect is moderate, and if the impact size is = 0.8 The effect is significant), (Asr, 2003). From the above it is clear that the training program contributed to the development of the targeted web3.0 concepts for education technology specialists, as it found a difference between the median of the pre and post applications to test the concepts of the web3.0 in favor of the post application at the research group, which averaged (51,85) compared to (16) , 75) for pre-application, with a large effect size of (0.98) according to the ETA square measure (2η) of the effect size.


2017 ◽  
Vol 124 (2) ◽  
pp. 329-350 ◽  
Author(s):  
Giovani S. Cunha ◽  
Sean P. Cumming ◽  
João Valente-dos-Santos ◽  
João P. Duarte ◽  
Gustavo Silva ◽  
...  

This study examined power output on jumping and sprinting tests in young soccer players of differing pubertal status, while controlling for body size with allometric scaling exponents. A total of 46 males aged 12–18 years (14.17 years) were divided into three groups: pre-pubescent ( n = 12), pubescent ( n = 22), and post-pubescent ( n = 12). Participants performed a series of tests, including the squat jump (SJ), countermovement jump (CMJ), and 10-meter and 30-meter sprint test protocols. The Post-PUB group was older ( F = 112.411, p < 0.001), more experienced in competitive soccer ( F = 8.055, p = 0.001), taller ( F = 28.940, p < 0.001), and heavier ( F = 20.618, p < 0.001), when compared to peers in the other groups. Mean differences in jumping and sprinting performances suggested a significant effect for pubertal status on performance in the 10-meter sprint (large effect size, F = 8.191, p < 0.001) and 30-meter sprint (large effect size, F = 8.093, p < 0.001) after allometric scaling. Power output derived from SJ (small effect size, F = 0.536, p = 0.001) and CMJ (small effect size, F = 1.058, p = 0.356) showed no significant differences across players of varying pubertal status. Biological maturation showed a large effect on maximal power output for sprints, but not for jumps, when the effect of body size was adjusted by statistically derived allometric exponents in young male soccer players.


2021 ◽  
Vol 11 ◽  
Author(s):  
Martin Götze ◽  
Matthias W. Hoppe

The relative age effect (RAE) is associated with (dis)advantages in competitive sports. While the RAE in elite male soccer reveals a skewed birthdate distribution in relation to a certain cut-off date, research of RAE in elite female soccer is affected by small number of samples and conflicting results. The purpose of this study was to investigate the RAE in elite adult German soccer regarding gender and competition level. The sample comprised 680 female and 1,083 male players of the two top German leagues during the 2019/20 season and German national teams (A-Team to Under 19). Differences between the observed and expected birthdate distributions were analyzed using chi-square statistics and effect sizes followed by calculating odds ratios. Results showed a statistically significant RAE with small effect size across all players included for both genders (female players: P &lt; 0.001, W = 0.16, male players: P &lt; 0.001, W = 0.23). The identified RAE was based on an over-representation of players born at the beginning of the year. According to gender and competition level, RAEs were more pronounced in German male soccer. While significant RAEs were found among males in the first two leagues (first league: P &lt; 0.001, W = 0.19, second league: P &lt; 0.001, W = 0.26), the RAE of females was more pronounced in the second league (first league: P = 0.080, W = 0.16, second league: P = 0.002, W = 0.20). The analysis of RAE regarding the national teams revealed a statistically significant RAE with large effect size for only the youngest investigated age group of male players (Under 19: P = 0.022, W = 0.52). Our data show an RAE in female and male German adult soccer, which could be accompanied by a loss of valuable elite players during the youth phase of the career. Consequently, the pool of talented players at the adult level would be limited.


10.2196/12967 ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. e12967 ◽  
Author(s):  
Bhone Myint Kyaw ◽  
Pawel Posadzki ◽  
Sophie Paddock ◽  
Josip Car ◽  
James Campbell ◽  
...  

Background Effective communication skills are essential in diagnosis and treatment processes and in building the doctor-patient relationship. Objective Our aim was to evaluate the effectiveness of digital education in medical students for communication skills development. Broadly, we assessed whether digital education could improve the quality of future doctors’ communication skills. Methods We performed a systematic review and searched seven electronic databases and two trial registries for randomized controlled trials (RCTs) and cluster RCTs (cRCTs) published between January 1990 and September 2018. Two reviewers independently screened the citations, extracted data from the included studies, and assessed the risk of bias. We also assessed the quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations assessment (GRADE). Results We included 12 studies with 2101 medical students, of which 10 were RCTs and two were cRCTs. The digital education included online modules, virtual patient simulations, and video-assisted oral feedback. The control groups included didactic lectures, oral feedback, standard curriculum, role play, and no intervention as well as less interactive forms of digital education. The overall risk of bias was high, and the quality of evidence ranged from moderate to very low. For skills outcome, meta-analysis of three studies comparing digital education to traditional learning showed no statistically significant difference in postintervention skills scores between the groups (standardized mean difference [SMD]=–0.19; 95% CI –0.9 to 0.52; I2=86%, N=3 studies [304 students]; small effect size; low-quality evidence). Similarly, a meta-analysis of four studies comparing the effectiveness of blended digital education (ie, online or offline digital education plus traditional learning) and traditional learning showed no statistically significant difference in postintervention skills between the groups (SMD=0.15; 95% CI –0.26 to 0.56; I2=86%; N=4 studies [762 students]; small effect size; low-quality evidence). The additional meta-analysis of four studies comparing more interactive and less interactive forms of digital education also showed little or no difference in postintervention skills scores between the two groups (SMD=0.12; 95% CI: –0.09 to 0.33; I2=40%; N=4 studies [893 students]; small effect size; moderate-quality evidence). For knowledge outcome, two studies comparing the effectiveness of blended online digital education and traditional learning reported no difference in postintervention knowledge scores between the groups (SMD=0.18; 95% CI: –0.2 to 0.55; I2=61%; N=2 studies [292 students]; small effect size; low-quality evidence). The findings on attitudes, satisfaction, and patient-related outcomes were limited or mixed. None of the included studies reported adverse outcomes or economic evaluation of the interventions. Conclusions We found low-quality evidence showing that digital education is as effective as traditional learning in medical students’ communication skills training. Blended digital education seems to be at least as effective as and potentially more effective than traditional learning for communication skills and knowledge. We also found no difference in postintervention skills between more and less interactive forms of digital education. There is a need for further research to evaluate the effectiveness of other forms of digital education such as virtual reality, serious gaming, and mobile learning on medical students’ attitude, satisfaction, and patient-related outcomes as well as the adverse effects and cost-effectiveness of digital education.


2018 ◽  
Vol 13 (7) ◽  
pp. 897-902 ◽  
Author(s):  
Pedro G. Morouço ◽  
Tiago M. Barbosa ◽  
Raul Arellano ◽  
João P. Vilas-Boas

Context: In front-crawl swimming, the upper limbs perform alternating movements with the aim of achieving a continuous application of force in the water, leading to lower intracyclic velocity variation (dv). This parameter has been identified as a crucial criterion for swimmers’ evaluation. Purpose: To examine the assessment of intracyclic force variation (dF) and to analyze its relationship with dv and swimming performance. Methods: A total of 22 high-level male swimmers performed a maximal-effort 50-m front-crawl time trial and a 30-s maximal-effort fully tethered swimming test, which were randomly assigned. Instantaneous velocity was obtained by a speedometer and force by a strain-gauge system. Results: Similarity was observed between the tests, with dF attaining much higher magnitudes than dv (P < .001; d = 8.89). There were no differences in stroke rate or in physiological responses between tethered and free swimming, with a high level of agreement for the stroke rate and blood lactate increase. Swimming velocity presented a strong negative linear relationship with dF (r = −.826, P < .001) and a moderate negative nonlinear relationship with dv (r = .734, P < .01). With the addition of the maximum impulse to dF, multiple-regression analysis explained 83% of the free-swimming performance. Conclusions: Assessing dF is a promising approach for evaluating a swimmer’s performance. From the experiments, this new parameter showed that swimmers with higher dF also present higher dv, leading to a decrease in performance.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Pedro G. Morouço ◽  
Daniel A. Marinho ◽  
Mikel Izquierdo ◽  
Henrique Neiva ◽  
Mário C. Marques

The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female) randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking). A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50 m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking. Estimated relative contributions of arm stroke and leg kicking were 70.3% versus 29.7% for males and 66.6% versus 33.4% for females, with 15.6% and 13.1% force deficits, respectively. To obtain higher velocities, male swimmers are highly dependent on the maximum forces they can exert with the arm stroke (r=0.77,P<0.01), whereas female swimmers swimming velocity is more related to whole-body mean forces (r=0.81,P<0.01). The obtained results point that leg kicking plays an important role over short duration high intensity bouts and that the used methodology may be useful to identify strength and/or coordination flaws.


2018 ◽  
Vol 63 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Charlini S. Hartz ◽  
Márcio A. G. Sindorf ◽  
Charles R. Lopes ◽  
José Batista ◽  
Marlene A. Moreno

Abstract Inspiratory muscle training (IMT) is a strategy that has been used to improve performance in different sports modalities. This study investigated the effects of an IMT program on respiratory muscle strength and resistance as well as aerobic physical performance (PP) of handball athletes. Nineteen 20 ± 3 year-old male athletes were allocated into an experimental (EG, n = 10) or a placebo group (PG, n = 9). Their respiratory muscle strength was evaluated by measuring the maximum inspiratory and expiratory pressures (MIP and MEP), muscular respiratory resistance by maximum voluntary ventilation (MVV) and aerobic PP by the cardiopulmonary exercise test. The study was designed to evaluate the effects of a 12-week IMT program with five sessions a week. A significant difference was observed in the pre and post IMT values of the MIP (170 ± 34 to 262 ± 33 cmH2O) and MEP (177 ± 36 to 218 ± 37 cmH2O) in the EG, and MIP (173 ± 45 to 213 ± 21 cmH2O) in the PG, with a large effect size for the MIP, when the groups were compared. MVV showed a significant increase (162 ± 24 to 173 ± 30 L) in the EG, with a small effect size. There was a significant difference in maximum oxygen uptake (54 ± 8 to 60 ± 7 ml/kg/min) in aerobic PP. Oxygen uptake at the respiratory compensation point (RCP) (46 ± 6 to 50 ± 5 ml/kg/min), with a moderate effect size for both variables, was observed in the EG after IMT. We concluded that IMT provided a significant increase in respiratory muscle strength and resistance, contributing to increased aerobic PP in the EG, which suggests that IMT could be incorporated in handball players’ training.


2012 ◽  
Vol 34 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Daniel López-Plaza ◽  
Fernando Alacid ◽  
Pedro A. López-Miñarro ◽  
José M. Muyor

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.


2021 ◽  
Vol 26 (3) ◽  
pp. 72-80
Author(s):  
Aleksandra Stoiljković ◽  
Slavica Tomić ◽  
Ozren Uzelac

Capital structure refers to the combination of debt and equity that the company uses to finance overall operations and growth. One of the most common problems of small enterprises is difficult access to various sources of financing, which is certainly reflected in their capital structure. Deciding on capital structure is one of the most important activities in the company, given that it significantly determines the performance of the company, but also the competitiveness and sustainability of the business. The aim of the study was to investigate whether there is a significant difference in financial performance between enterprises belonging to different leverage levels. Financial leverage was calculated by dividing total debts to total assets and based on leverage the companies are divided into 3 groups. Using ANOVA analysis, we found that the only difference in financial performance indicators was observed with NPM (but with a small effect size: eta square = 0.0470), whereas no statistically significant difference was observed between the groups in the ROE and ROA indicators.


Author(s):  
Ailene Lumanog ◽  
Myrna O. Medrano

The skills-based learning material was made and studied by the researcher due to sudden changes in education in a time of the pandemic. The main focus of this study is to determine the effectiveness of the skills-based learning material for English 9. This study used the pretest-posttest non-equivalent control group design, which falls under the quasi-experimental design. On the test of significant difference between the formative mean scores of the experimental and comparison groups, it was found out that the formative tests had a significant effect on the respondents' learning performance at p 0.01 level. Additionally, the posttest mean scores of each group; got the 0.01 level of significance, as well as the pretest and posttest mean scores of each group. Moreover, based on the computed Cohen's d value of 1.16, the effect size of the learning material to the students' performance is large compared to the comparison group that shows a small effect size at 0.31 Cohen's d value. Generally, there is a significant difference between the formative test of the two groups with the average and high mean scores, respectively. There is also a significant difference between the posttest mean scores of the two groups and as well between the pre-test and post-test mean scores. Moreover, Cohen's effect size value of 1.16 suggested a large effect of the material on the respondents' learning performance. As for recommendations, there is a need for the teacher to incorporate the 21st Century Skills into learning competencies.  


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