Dejan Madić

Differences in the Efficiency Between the Grab and Track Starts for Both Genders in Greek Young Swimmers

Differences in the Efficiency Between the Grab and Track Starts for Both Genders in Greek Young Swimmers The aim of this study was to determine the differences in the kinematic parameters between the grab and track starts and the differences in these two starts between genders. A total of 27 swimmers at the competitive level participated in the study, 13 boys (mean ± SD: age 15.8 ± 0.8 years, body mass 67.7 ± 7.7 kg and body height 178.6 ± 5.7 cm) and 14 girls (mean ± SD: age 16 ± 0.8 years, body mass 59.2 ± 6.6 kg and body height 166.2 ± 6.7 cm). Each swimmer performed three attempts for both start techniques. The best attempt of the grab start and the track start was taken for further analysis. The following kinematic parameters were analysed: flight distance, flight time, flight velocity, entry angle and reaction time. The males had greater numeric values for the results in all kinematic parameters for the grab start compared with the track start, except for flight velocity and entry angle (flight time 0.42 vs. 0.41 s, flight distance 3.21 vs. 3.14 m, flight velocity 7.76 vs. 7.83 m/s, entry angle 44.22 vs. 43.85 degrees and reaction time 0.86 vs. 0.81 s). The females also had greater numeric values for the results in all kinematic parameters for the grab start compared with the track start, except for flight time (flight time 0.38 vs. 0.38 s, flight distance 2.82 vs. 2.73 m, flight velocity 7.47 vs. 7.31 m/s, entry angle 45.18 vs. 44.79 degrees and reaction time 0.88 vs. 0.82 s). These results indicate that the males had significantly better results for flight time and flight distance compared with the females for the grab start (flight time 0.42 vs. 0.38 s, flight distance 3.21 vs. 2.82 m). In the case of the track start, the males had significantly better results for flight distance (3.14 vs. 2.73 m). Exploring the characteristics of the two starts did not lead to any significant kinematic differences. Therefore, a conclusion that demonstrates the superiority of one of the techniques cannot be reached. The coach, together with each swimmer individually, should devote some time to decide after some tests what type of start is better for the body type and general qualifications of the swimmer.

Osteoid osteoma: fluoroscopic guided percutaneous excision technique - our experience.

Osteoid osteoma is a small benign bone lesion. It generally affects children and young adults. Traditional treatment of osteoid osteoma includes excision either by wide resection, or by the removal of the nidus using curettes and burrs after opening the overlying cortex. Newly developed techniques involve percutaneous ablation of the tumor by computed tomography-guided core-drill excision and destruction of the nidus by thermocoagulation. Fluoroscopic guided percutaneous extirpation and drilling resection procedures have been performed at the Institute for Health Care of Children and Youth, Pediatric Surgery Clinic in Novi Sad, Serbia. Some modifications in the methods were made and implemented, which resulted in an excellent cost–benefit ratio, shorter period of hospitalization, and faster recovery. The aim of this paper is to present the experience gained in the treatment of osteoid osteomas in the last 5 years at the Pediatric Surgery Clinic in Novi Sad and to describe the modifications to the percutaneous biopsy technique of osteoid osteoma that have been implemented.

The Influence of Familiarization on Physical Fitness Test Results in Primary School-Aged Children

PURPOSE The number of familiarization sessions in fitness assessments seems to be critical and inconsistent. Therefore, the primary aim of this research was to determine the number of familiarization attempts that stabilize the results in particular physical fitness tests. The secondary aim was to establish the test reliability through familiarization sessions. METHODS Thirty-nine primary school children participated in this research (age: 10.8 years, body mass: 40.6 ± 8.9 kg, and body height: 145.3 ± 7.2 cm). During six sessions, with one session every third day, participants performed the following tests to assess explosive strength (vertical jump and standing long jump), coordination (polygon backward and polygon with turn) and flexibility (toe touch). RESULTS The results of repeated analysis of variance (ANOVA) showed that there were significant increases (p < .05) in the polygon backward and polygon with turn performances from the first to third familiarization session. The standard error of measurement decreased as sessions progressed, indicating little within subject variation between the coordination test results following a familiarization period. Statistically significant differences were identified in the vertical jump test from the fourth test session compared with the first session. On the other hand, statistically significant differences for the standing long jump test were only found in the final session compared with the initial session. In the toe touch test, there were no significant increases from the first to the final familiarization session. All tests showed high a reliability coefficients, ranging from 0.979 to 0.991. CONCLUSION Polygon backward and polygon with turn performance may be a practical, reliable method to assess coordination in primary school-aged children. However, completion of at least 3 practice sessions is suggested for participants to obtain a stable score. In addition, both jump tests are feasible for assessing skill-related fitness in young children, although the scientific reliability of the two tests should be questioned and the tests should be tailored to fit the age group of the children.

ADAPTED PHYSICAL ACTIVITY IN THE PREVENTION AND THERAPY OF OSTEOPOROSIS

INTRODUCTION Osteoporosis, a disease characterized by the progressive loss of bone tissue, is one of the most common complications of aging. EPIDEMIOLOGY According to some calculations, there were 25% of women and 4% of men older than 50 years with osteoporosis in the world in 2010. It is assumed that the number of patients with osteoporosis will increase by 30% in every 10 years in the 21st century. There are many reasons for that: the worlds population is growing older, diet is getting poorer in vitamins and minerals and physical activity is decreasing. THE QUALITY AND QUANTITY OF BONE TISSUE: Developing bones are much more responsive to mechanical loading and physical activity than mature bones. This suggests that training in early childhood may be an important factor in the prevention of osteoporosis in later life. It is important to note that the quality of bone achieved by training at younger age cannot be maintained permanently if it is not supported by physical activity later in life. Adapted physical activity represents physical activity individually tailored according to the psychosomatic capabilities of a person and the goal to be achieved. It can be applied at any age in order to maintain strong bones and reduce the risk of fracture. Adapted physical activity is different for men and women, for different age, as well as for the individuals. Aerobic exercises, which lead to an acceleration of breathing, increased heart rate and mild perspiration, as well as resistance exercises and exercises against resistance done by stretching elastic bands, for hands, legs and torso have been proven to increase bone density and improve bone strength. Coordination and balance exercises are important in an individual workout program. An explanation of the action of adapted physical activity is the basis for the theory of control and modulation of bone loss, muscle strength, coordination and balance. Physical activity is very effective in reducing sclerostin, which is known to inhibit bone formation. In addition, physical training enhances the levels of insulinlike growth factor, which has a very positive effect on bone formation. CONCLUSION The aim of adapted physical activity is to improve bone formation in youngsters, to preserve the bone mass in adults and to prevent the bone loss in the elderly thus reducing the risk of falls and resulting fractures; in other words, to minimize the disability caused by fractures and improve the quality of life.

Relationship Between Morphological Characteristics and Match Performance in Junior Soccer Players

Soccer players are usually selected based on their anthropometry characteristics rather than their performances. Therefore, the purpose of this cross-sectional study was to examine the relationship between morphological and match performances among junior soccer players. Thirty seven junior soccer players were randomly selected using as stratification criteria age and playing role. Skinfolds (mm) were measured at six sites: triceps skinfold thickness, subscapular skinfold thickness, thigh skinfold thickness, calf skinfold thickness, supraspinal skinfold thickness and abdominal skinfold thickness. In addition, total distance covered during the match, as well as the distance traveled by walking, jogging, moderate and high intensity running and sprinting was determined. The total distance covered was associated with subscapular and abdominal skinfolds. In addition, the subscapular skinfolds were significantly related to high intensity running and sprinting. No other statistically significant correlations were found among other skinfold and performance parameters. The present study showed no significant relationships between morphological and match performances among junior soccer players. Our study supports the conclusions that beside the anthropometry advantage, psychological and soccer-specific skills should be also considered in the selection of soccer players.

Molecular Hydrogen Supplementation and Multiple Sprint Running Performance; a Pilot Investigation.: 903 Board #219 June 1, 3

Recently it has been suggested that molecular hydrogen could attenuate performance decrement during high intensity, short duration interval exercise. Antioxidant properties of molecular hydrogen indicate that it might be beneficial for reducing oxidative stress induced muscle performance decrements.

relacije bazičnih i sPecifičnih motoričkih sPosobnosti sa rezultatima Plivanja u Prsnoj tehnici kod mladih Plivača

Cilj trenažnog procesa u plivanju je razvoj onih antropoloskih karakteristika i sposobnosti od kojih najvise zavisi rezultat. Cilj ovog rada je utvrditi uticaj određenih bazicnih i specificnih motorickih sposobnosti na rezultate u disciplini 100 m prsno kod mladih plivaca. Uzorak ispitanika je cinilo 30 plivaca starosti od 9 do 12 godina koji pripadaju kategoriji mlađih pionira. Prediktorski skup je cinilo 8 varijabli za procenu bazicnih i 6 za procenu specificnih motorickih sposobnosti. Kao kriterijumska varijabla koriscen je rezultat plivanja u disciplini 100 metara prsno u velikom bazenu. Rezultati regresionih analiza su pokazali da u celini oba seta primenjenih varijabli imaju znacajnu korelaciju sa rezultatima u disciplini 100 metara prsno. Posmatrano pojedinacno nijedna varijabla nema statisticki znacajan uticaj. Tako dobijeni podaci ukazuju da u trenažnom procesu sa mlađim kategorijama treba stvoriti optimalne uslove za razvoj svih motorickih sposobnosti koje mogu imati uticaj na plivacku efikasnost u prsnoj tehnici.