scholarly journals Athletic performance, training characteristics, and orthopedic indications in junior tennis Davis Cup players

2020 ◽  
Author(s):  
Janina Fett ◽  
Alexander Ulbricht ◽  
Thimo Wiewelhove ◽  
Alexander Ferrauti
Keyword(s):  
Performance Enhancement ◽  
Musculoskeletal Symptoms ◽  
Training Volume ◽  
Performance Training ◽  
Orthopedic Injury ◽  
Two Samples ◽  
High Prevalence ◽  
Junior Tennis ◽  
And Performance ◽  
The Impact

Our study aimed to examine athletics, training characteristics, and prevalence of musculoskeletal symptoms of male junior tennis Davis Cup players (DC) in comparison with their regional counterparts, as well as to evaluate the impact of age and performance level on training characteristics. Twelve junior DC (male) and two samples of regional squad players (RS1 n = 60 males, n = 47 females; RS2 n = 59 males) participated in a physical testing, an interview for data evaluation on training characteristics, and a questionnaire survey of orthopedic injury frequency. Results indicate higher physical performance levels (effect size (ES) 0.75–1.26) and training volumes in DC (ES 1.23–1.66). In DC, significant relationships were found between total training volume and tennis ranking (r = −0.78), age and physical training volume (r = 0.82), and age and total training volume (r = 0.62). Injury frequencies showed moderate to high prevalence with no differences (p > 0.05) between DC and RS. Given the demands of elite tennis and the important role of service in the modern game, more efforts are necessary to develop training prescription for both performance enhancement and prevention strategies.

scholarly journals Athletic performance, training characteristics, and orthopedic indications in junior tennis Davis Cup players

2016 ◽  
Vol 12 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Janina Fett ◽  
Alexander Ulbricht ◽  
Thimo Wiewelhove ◽  
Alexander Ferrauti
Keyword(s):  
Performance Enhancement ◽  
Musculoskeletal Symptoms ◽  
Training Volume ◽  
Performance Training ◽  
Orthopedic Injury ◽  
Two Samples ◽  
High Prevalence ◽  
Junior Tennis ◽  
And Performance ◽  
The Impact

Our study aimed to examine athletics, training characteristics, and prevalence of musculoskeletal symptoms of male junior tennis Davis Cup players (DC) in comparison with their regional counterparts, as well as to evaluate the impact of age and performance level on training characteristics. Twelve junior DC (male) and two samples of regional squad players (RS1 n = 60 males, n = 47 females; RS2 n = 59 males) participated in a physical testing, an interview for data evaluation on training characteristics, and a questionnaire survey of orthopedic injury frequency. Results indicate higher physical performance levels (effect size (ES) 0.75–1.26) and training volumes in DC (ES 1.23–1.66). In DC, significant relationships were found between total training volume and tennis ranking ( r = −0.78), age and physical training volume ( r = 0.82), and age and total training volume ( r = 0.62). Injury frequencies showed moderate to high prevalence with no differences ( p > 0.05) between DC and RS. Given the demands of elite tennis and the important role of service in the modern game, more efforts are necessary to develop training prescription for both performance enhancement and prevention strategies.

scholarly journals Kinematic characteristics of the tennis serve from the ad and deuce court service positions in elite junior players

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0252650
Author(s):  
Janina Fett ◽  
Nils Oberschelp ◽  
Jo-Lâm Vuong ◽  
Thimo Wiewelhove ◽  
Alexander Ferrauti
Keyword(s):  
Skill Acquisition ◽  
Performance Enhancement ◽  
Ball Impact ◽  
Tennis Players ◽  
Starting Position ◽  
Target Field ◽  
Junior Tennis ◽  
Tennis Serve ◽  
Multiple Characteristics ◽  
And Performance

Purpose According to the official rules of the International Tennis Federation, players have to serve alternately from two different positions: the deuce (right, D) and the ad court (left, AD) side. This study aimed to compare body and ball kinematics of flat serves from both service sides. Methods In a controlled, semi-court laboratory setting, 14 elite male junior players served eight flat first serves to a target field directed to the receiver’s body from both service positions in a matched and counterbalanced order. An 8-camera-Vicon-System was used to capture the 3D-landmark trajectories. Results The mean service velocity was found to be similar on both sides (D: 151.4 ± 19.8 vs. AD: 150.5 ± 19.4 km/h), while multiple characteristics of the serve and ball kinematics differed significantly (p < .05). At starting, the front-foot angle relative to the baseline (D: 39.7±17.6° vs. AD: 31.1±17.4°) and lateral distance between the feet (D: 16.3 ± 12.9 cm vs. AD: 26.2 ± 11.9 cm) were significantly different. During the service, upper torso range of motion from maximum clockwise rotation until impact was significantly greater on the deuce court (D: 130.5 ± 19.8° vs. AD: 126.7 ± 21.1°). This was especially pronounced in foot-back technique players. Further, differences in the lateral ball impact location (D: 30.0 ± 24.1 cm vs. AD: 10.3 ± 23.3 cm) were observed. Conclusions Changing the service side affects the serve and ball kinematics in elite junior tennis players. Our results underline biomechanical differences regarding the starting position (feet and upper torso) as well as the movement and ball kinematics which could be relevant for skill acquisition, injury prevention and performance enhancement.

scholarly journals A grinding-burnishing approach to enhancing surface integrity, tribological and corrosion behaviour of laser-cladded AISI 431 alloys

2021 ◽  
pp. 1-15
Author(s):  
Mohammad Uddin ◽  
Remi Santifoller ◽  
Colin Hall ◽  
Thomas Schlaefer
Keyword(s):  
Corrosion Resistance ◽  
Surface Integrity ◽  
Performance Enhancement ◽  
Corrosion Behaviour ◽  
Impact Resistance ◽  
Corrosion Current ◽  
Surface Alteration ◽  
Modification Technique ◽  
And Performance ◽  
The Impact

Abstract This paper presents the influence of the grinding-burnishing on surface integrity and corrosion performance of the laser-cladded AISI 431 alloys. As-cladded specimens were first ground followed by plasticity ball burnishing. To evaluate surface alteration and performance enhancement, six major properties were measured and analysed in terms of surface roughness, porosity, microhardness, wear, and impact and corrosion resistance. Results showed that grinding-burnishing significantly improved the surface finish by lowering Ra and Rz by up to 29% and 41%, respectively, compared to grinding, while surface porosity was found to decrease by 18%. Maximum surface microhardness increased by 32% when grinding-burnishing, with a modified depth of up to 250 μm, while wear resistance increased by up to 38%. Because of hardness improvement, the grinding-burnishing increased the impact resistance by lowering the maximum indent depth by 29%. The corrosion resistance improved by increasing positive corrosion potential from − 0.31 V (grinding) to − 0.21 V (grinding-burnishing) and lowering corrosion current density from 1.18 × 10−3 A.cm−2 (for grinding) to 2.1 × 10−5 A.cm−2 (grinding-burnishing). Burnishing further induced grain modification in terms of grain deformation and flattening within microstructure, but no significant grain refinement was observed. XRD results however showed lattice deformation indicating potential compressive residual stress generated by burnishing. Overall, it is imperative to say that the combined grinding-burnishing can be a viable surface modification technique to extend functional service life of the laser-cladded components.

scholarly journals AN EXPLORATION OF THE IMPACT OF HOTEL FACILITIES ON EMPLOYEE MOTIVATION AND PERFORMANCE: AN INDONESIA CASE STUDY

2021 ◽  
Vol 1 (1) ◽  
pp. 25-47
Author(s):  
Nadhira Sukmana Putri
Keyword(s):  
Performance Enhancement ◽  
Well Being ◽  
Employee Motivation ◽  
Training And Development ◽  
Employee Productivity ◽  
Employee Morale ◽  
And Performance ◽  
Beach Resort ◽  
The Impact

The purpose of this study is to examine the impact of staff facilities on employee motivation and performance by using a case-study of Oberoi Beach Resort – a five-star hotel situated in Lombok, Indonesia. This study begins with a review of the research background, aim, and objectives. The author then addressed issues in the hospitality industry and the importance of maintaining employee morale and productivity. Next, the main topics of this study, i.e. employee productivity & well-being, staff facilities, motivation, and performance were analyzed. Such topics were narrowed and established as the basis for primary research. Mixed-method approach was adopted to verify theories with acquired data. Despite several limitations, this research found that wages, events for staff, and medical-room are effective in motivating them to perform better and to stay with the brand. Additionally, training and development is the best tool for performance enhancement.

The impact of acute stress on the neural processing of food cues in bulimia nervosa: Replication in two samples.

2017 ◽  
Vol 126 (5) ◽  
pp. 540-551 ◽  
Author(s):  
Brittany Collins ◽  
Lauren Breithaupt ◽  
Jennifer E. McDowell ◽  
L. Stephen Miller ◽  
James Thompson ◽  
...  
Keyword(s):  
Bulimia Nervosa ◽  
Acute Stress ◽  
Neural Processing ◽  
Food Cues ◽  
Two Samples ◽  
The Impact

The Impact of Property Characteristics on Economic Performance of Russian Industrial Enterprises

2005 ◽  
pp. 53-68 ◽  
Author(s):  
R. Kapeliushnikov ◽  
N. Demina
Keyword(s):  
Detailed Analysis ◽  
Economic Performance ◽  
Ownership Concentration ◽  
Corporate Sector ◽  
Concentrated Ownership ◽  
Industrial Enterprises ◽  
Russian Industry ◽  
Control Premium ◽  
And Performance ◽  
The Impact

The paper provides new survey evidence on effects of concentrated ownership upon investment and performance in Russian industrial enterprises. Authors trace major changes in their ownership profile, assess pace of post-privatization redistribution of shareholdings and provide evidence on ownership concentration in the Russian industry. The major econometric findings are that the first largest shareholding is negatively associated with the firm’s investment and performance but surprisingly the second largest shareholding is positively associated with them. Moreover, these relationships do not depend on identity of majority shareholders. These results are consistent with the assumption that the entrenched controlling owners are engaged in extracting "control premium" but sizable shareholdings accumulated by other blockholders may put brakes on their expropriating behavior and thus be conductive for efficiency enhancing. The most interesting topic for further more detailed analysis is formation, stability and roles of coalitions of large blockholders in the corporate sector of post-socialist countries.

The Impact of Women’s Employment on Marital Stability in Qatar Society

2019 ◽  
Vol 10 (2) ◽  
pp. 144-151
Author(s):  
Noora Ahmed Lari ◽  
Keyword(s):  
Work Motivation ◽  
Marital Stability ◽  
Female Employment ◽  
Social Constraints ◽  
Primary Data ◽  
Family Policies ◽  
Insufficient Time ◽  
And Performance ◽  
The Impact ◽  
The Relationship

The State of Qatar has implemented several family policies in order to improve the wellbeing of Qatari families and ensure fair distribution of development benefits for both men and women. However, there is a linkage between female employment outside the home and instability in the marriages of Qatari families. This paper investigates the impact of female employment on marital stability, based on the results of primary data collected in Qatar, a questionnaire that consisted of several sections such as challenges in the workplace, supervisor, family and spouse relations, work motivation and performance. Of the 824 questionnaires that were returned, 807 were completed and valid for analysis. Regression analysis and an ANOVA test have been used to test the relationship between the variables. The results of the research have produced mixed findings about how wives’ employment increases marital instability and have yielded few significant differences on mean scores of discuss on work demands, insufficient time together, housework, financial matters, communication, relatives and rearing children. The results indicates that in general Qatar working women face several challenges in relation to their marital life as part of cultural and social constraints.

Comparing the Impact of Religious Discourse on HIV/AIDS in Islam and Christianity in Africa

2012 ◽  
Vol 8 ◽  
Author(s):  
Sloane Speakman
Keyword(s):  
Social Factors ◽  
Negative Relationship ◽  
Hiv Prevalence ◽  
Religious Discourse ◽  
Prevalence Rates ◽  
The Social ◽  
High Prevalence ◽  
Islam And Christianity ◽  
Sub Saharan ◽  
The Impact

In examining the strikingly high prevalence rates of HIV in many parts of Africa, reaching as high as 5% in some areas, how does the discourse promoted by the predominant religions across the continent, Islam and Christianity, affect the outlook of their followers on the epidemic? This question becomes even more intriguing after discovering the dramatic difference in rate of HIV prevalence between Muslims and Christians in Africa, confirmed by studies that have found a negative relationship to exist between HIV prevalence and being Muslim in Africa, even in Sub-Saharan African nations. Why does this gap in prevalence rates exist? Does Islam advocate participating in less risky behavior more so than Christianity? By comparing the social construction, epidemiological understanding and public responses among Muslim populations in Africa with Christian ones, it becomes apparent that many similarities exist between the two regarding discourse and that, rather than religious discourse itself, other social factors, such as circumcision practices, contribute more to the disparity in HIV prevalence than originally thought.

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