28 research outputs found
Foot morphology of Turkish football players according to foot preference
Football is the most popular sport in the world. Foot morphology and foot preference are important factors in football player’s performance. The aim of this cross-sectional study was to evaluate the foot morphology of elite football players with different foot preferences. 407 male football players participated in this study. 328 of them preferred their right foot, while 79 of them preferred the left one. Eleven anthropometric measurements were taken from each foot with standard anthropometric methods. Foot length, T1, T2, T3, T4 and T5 lengths, foot circumference of right and left feet and right foot width of right foot preference group were higher than those of left foot preference group, which is statistically significant (p < 0.05). Left foot measurements of right foot preference group were interestingly higher than those of the right side. It was suggested that these data may be useful to define the foot morphology of elite football players.Key words: Foot morphology, football, measurements
High Power CMUTs: Design and experimental verification
Cataloged from PDF version of article.Capacitive micromachined ultrasonic transducers
(CMUTs) have great potential to compete with piezoelectric
transducers in high-power applications. As the output pressures
increase, nonlinearity of CMUT must be reconsidered
and optimization is required to reduce harmonic distortions.
In this paper, we describe a design approach in which uncollapsed
CMUT array elements are sized so as to operate at the
maximum radiation impedance and have gap heights such that
the generated electrostatic force can sustain a plate displacement
with full swing at the given drive amplitude. The proposed
design enables high output pressures and low harmonic
distortions at the output. An equivalent circuit model of the
array is used that accurately simulates the uncollapsed mode
of operation. The model facilities the design of CMUT parameters
for high-pressure output, without the intensive need
for computationally involved FEM tools. The optimized design
requires a relatively thick plate compared with a conventional
CMUT plate. Thus, we used a silicon wafer as the CMUT
plate. The fabrication process involves an anodic bonding process
for bonding the silicon plate with the glass substrate. To
eliminate the bias voltage, which may cause charging problems,
the CMUT array is driven with large continuous wave
signals at half of the resonant frequency. The fabricated arrays
are tested in an oil tank by applying a 125-V peak 5-cycle
burst sinusoidal signal at 1.44 MHz. The applied voltage is increased
until the plate is about to touch the bottom electrode
to get the maximum peak displacement. The observed pressure
is about 1.8 MPa with −28 dBc second harmonic at the
surface of the array
Dual-electrode CMUT with non-uniform membranes for high electromechanical coupling coefficient and high bandwidth operation
In this paper, we report measurement results on dual-electrode CMUT demonstrating electromechanical coupling coefficient (k(2)) of 0.82 at 90% of collapse voltage as well as 136% 3 dB one-way fractional bandwidth at the transducer surface around the design frequency of 8 MHz. These results are within 5% of the predictions of the finite element simulations. The large bandwidth is achieved mainly by utilizing a non-uniform membrane, introducing center mass to the design, whereas the dual-electrode structure provides high coupling coefficient in a large dc bias range without collapsing the membrane. In addition, the non-uniform membrane structure improves the transmit sensitivity of the dual-electrode CMUT by about 2dB as compared with a dual electrode CMUT with uniform membrane
Foot morphology of Turkish football players according to foot preference
Football is the most popular sport in the world. Foot morphology and foot preference are important factors in football player's performance. The aim of this cross-sectional study was to evaluate the foot morphology of elite football players with different foot preferences. 407 male football players participated in this study. 328 of them preferred their right foot, while 79 of them preferred the left one. Eleven anthropometric measurements were taken from each foot with standard anthropometric methods. Foot length, T1, T2, T3, T4 and T5 lengths, foot circumference of right and left feet and right foot width of right foot preference group were higher than those of left foot preference group, which is statistically significant (p < 0.05). Left foot measurements of right foot preference group were interestingly higher than those of the right side. It was suggested that these data may be useful to define the foot morphology of elite football players. © 2011 Academic Journals
Evaluation of injuries in professional turkish football players [Profesyonel türk futbolcularinda travmanin degerlendirilmesi]
Aim: It is important to evaluate the injury patterns and anatomic localization of the injuries according to the playing position for the prevention of injuries and reduction of injury cost in football which is the most popular in the world. The purpose of this study was to evaluate the injury pattern and anatomical localization of injuries. Method: The injury pattern was evaluated with a questionnaire with the participation of 510 football players playing for the teams attending the First and Second Professional Turkish Leagues. Result: For different playing positions abrasions were 64.55-85.42%, muscular strains were 52.06-64.58%, joint sprains were 19.58-49.37% and fractures were 2.58-6.39% present. Regardless from the playing position lower extremity injuries were the most common injuries detected (60.5%). Conclusion: It was suggested that these data would be helpful for the reduction of injury risks and the costs besides with proper onsite precautions
Sport behaviors of Turkish soccer players: An observational study on personal and team-related dimensions
The current study aims to explore both personal and team-related sports behavior dimensions of Turkish children soccer players. It has been argued that several personal dispositions such as achievement motivation, fear of failure, and aggression levels (Wann, Haynes, McLean, and Pullen, 2003) could be at play when the child is trying to achieve in a sports context. Among related outcomes of these personal dispositions, sports performance, teamwork (Martin, Carron, Eys, and Loughead, 2012), fairplay and sportsmanship behaviors (Arthur-Banning, Wells, Baker, and Hegreness, 2009) have been widely researched and discussed in the literature. The current study will try to explore the relationships between these dimensions from a personal disposition perspective using an observational method. The sample consisted of 79 selected male soccer players. A total of 6 teams were observed during soccer play competition games. The results revealed interesting findings regarding the relationships between several personal and team-related behavior dimensions
Sport behaviors of Turkish soccer players: An observational study on personal and team-related dimensions
The current study aims to explore both personal and team-related sports behavior dimensions of Turkish children soccer players. It has been argued that several personal dispositions such as achievement motivation, fear of failure, and aggression levels (Wann, Haynes, McLean, and Pullen, 2003) could be at play when the child is trying to achieve in a sports context. Among related outcomes of these personal dispositions, sports performance, teamwork (Martin, Carron, Eys, and Loughead, 2012), fairplay and sportsmanship behaviors (Arthur-Banning, Wells, Baker, and Hegreness, 2009) have been widely researched and discussed in the literature. The current study will try to explore the relationships between these dimensions from a personal disposition perspective using an observational method. The sample consisted of 79 selected male soccer players. A total of 6 teams were observed during soccer play competition games. The results revealed interesting findings regarding the relationships between several personal and team-related behavior dimensions
Gonadal function in male mountain bikers
Yamaner, F, Atmaca, H, Bayraktaroglu, T, Aydin, M, and Aydemir, S. Gonadal function in male mountain bikers. J Strength Cond Res 25(8): 2311-2315, 2011-Some studies reported testicular disorders associated with biking in mountain cyclists, which include injuries, erectile dysfunction, and higher scrotal temperatures. But none of these studies evaluated gonadal function. Therefore, the aim of this study was to evaluate gonadal function in male mountain bikers. Twenty-two male professional mountain bikers and 30 healthy noncyclist controls were included in the study. The mean age and body mass index were similar in both groups. Fasting blood samples for the measurement of the levels of total testosterone (TT), sex-hormone binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were obtained from all study participants before any physical activity. In addition, because insulin sensitivity and leptin modulate gonadal function, the concentrations of insulin, glucose, and leptin were also measured in the same samples. Calculated free testosterone (cFT) and bioavailable testosterone (bioT) were calculated from SHBG and TT. Basal hormonal levels including insulin, leptin, LH, FSH, SHBG, TT, glucose, and homeostasis model assessment scores were similar between the groups. However, bioT and cFT levels were significantly lower (p ? 0.05) in the mountain bikers than those in the controls. Despite the lower mean testosterone levels in the study group, the levels of LH and FSH were similar to controls. Insulin and leptin do not contribute to lower testosterone levels. In conclusion, male mountain bikers have lower testosterone concentrations compared to controls. This alteration cannot solely be explained by testicular dysfunction. The etiology of lower testosterone levels in cyclists appears to be complex and requires further research. The influence of such a decline on the athlete's performance, quality of life, and muscle strength is not known as yet. © 2011 National Strength and Conditioning Association
Growth and pubertal development in adolescent male wrestlers
Background: Adolescence is a crucial period for linear growth, and sports training during this time may have positive or negative effects on some physiological processes as growth. The purpose of this study was to evaluate the effects of intense training during somatic growth on the onset of puberty and growth development in adolescent wrestlers. Methods: fifty adolescent male wrestlers and twenty-one sedentary healthy male controls aged between 13-15 years were selected. The wrestlers were from fve different wrestling schools and were active at competitive level. The maturity status of the subjects and data about the anthropometric characteristics including age, body weight, height, and Body Mass index (BMi) were evaluated. Serum testosterone, dehydroepiandrosterone sulphate, follicle stimulating hormone, luteinizing hormone, prolactin, cortisol, insulin like growth factor-1 (iGf-1), thyroid stimulating hormone (TSh) and free thyroxin were determined. Results: Anthropometric characteristics and puberty levels according to the Tanner stage were similar in both groups. There were no signifcant differences between wrestlers and sedentary control groups in sex hormones, cortisol, iGf-1, prolactin levels (p>0.05) but TSh concentrations differed signifcantly (P=0.015). Conclusions: The results suggested that training in adolescent male wrestlers did not signifcantly change resting sex hormones or alter the onset of puberty as determined by assessment of pubertal stages. The wrestlers had lower body fat and greater energy expenditure per week, there were no signifcant differences in height, weight, or BMI. © 2017 Edizioni Minerva Medica