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  • Author: Damir Sekulic x
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Damir Zubac, Hrvoje Karnincic and Damir Sekulic

Purpose: To examine the influence of rapid weight loss (RWL) on competitive success in elite youth Olympic-style boxers. In addition, this study examined the practice and prevalence of weight reduction, weight-management protocols, and related symptoms in youth boxers from 12 European countries (N = 83, all males, mean [SD] age 17.1 [0.9] y). Methods: The data were collected using an extensive questionnaire on weight cutting and its associated protocols and symptoms prior to highest-level continental championships. Competition results were obtained at follow-up using a dichotomous variable: medal winning vs nonwinning at the European Championships. Results: Binary logistic regression analysis indicated that “boxing experience” was significantly related to the criterion competitive outcome (odds ratio = 1.33; 95% confidence interval, 1.06–1.66; Nagelkerke R2 = .11), with a higher likelihood of competitive success for more-experienced boxers. Of all the youth boxers, only 25% were included in the RWL group, irrespective of their weight-class stratification. More than 45% of all the youth boxers self-reported the simultaneous combination of different weight-cutting methods that are known to be serious health hazards. Finally, 33% of the boxers experienced muscle weakness as a consequence of RWL. Conclusions: Our study provided evidence of pathogenic weight-management protocols that are widely adopted by youth boxers, and yet the present outcomes showed that RWL did not translate into competitive success in these elite Olympic-style boxers in Europe. Therefore, the authors suggest a mandatory educational program that should simultaneously target all the mentioned issues including both health- and performance-threatening consequences.

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Damir Sekulic, Sasa Krstulovic, Ratko Katic and Ljerka Ostojic

In this article we compared the effects of 9 months of judo training (JT; N = 41) and recreational sports games training (SGT; N = 57) on the fitness development of 7-year-old boys. Both programs were performed three times per week. Apart from body height, body weight, and skinfold thickness (SUM2SF), changes in muscular and cardiovascular endurance, flexibility, speed, agility, and coordination were studied. Using the analysis of variance, we found no differences between the groups at study entry, but after 9 months the JT participants achieved significantly better results in the shuttle-run task to test agility, the sit-up test for abdominal muscle endurance, and the sit-and-reach test for flexibility. The JT group also maintained their SUM2SF over the 9-month period, whereas the SGT group showed a significant increase in SUM2SF. No differences were observed between the groups in coordination, flexibility of the shoulder joint, speed, endurance, body height, and body weight. In conclusion, the specialized JT allowed the participants to improve more of their fitness capacities compared with nonspecialized SGT.

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Kemal Idrizovic, Bahri Gjinovci, Damir Sekulic, Ognjen Uljevic, Paulo Vicente João, Miodrag Spasic and Tine Sattler

Purpose: This study compared the effects of skill-based and plyometric conditioning (both performed in addition to regular volleyball training twice a week for 12 wk) on fitness parameters in female junior volleyball players. Methods: The participants [n = 47; age: 16.6 (0.6) y; mass: 59.4 (8.1) kg; height: 175.1 (3.0) cm] were randomized into a plyometric (n = 13), a skill-based (n = 17), and a control (n = 17) groups. The variables included body height, body mass, calf girth, calf skinfold, corrected calf girth, countermovement jump, 20-m-sprint, medicine ball toss, and sit-and-reach test. Results: Two-way analysis of variance (time × group) effects for time were significant (P < .05) for all variables except body mass. Significant group × time interactions were observed for calf skinfold [η2 = .14; medium effect size (ES)], 20-m sprint (η2 = .09; small ES), countermovement jump (η2 = .29; large ES), medicine ball (η2 = .58; large ES), with greater gains (reduction of skinfold) for plyometric group, and sit-and-reach (η2 = .35; large ES), with greater gains in plyometric and skill-based groups. The magnitude-based inference indicated positive changes in 1) medicine ball toss and countermovement jump for all groups; 2) sit-and-reach for the plyometric and skill-based groups; and 3) 20-m sprint, calf girth, calf skinfold, and corrected calf girth for plyometric group only. Conclusion: Selected variables can be improved by adding 2 plyometric training sessions throughout the period of 12 weeks. Additional skill-based conditioning did not contribute to improvement in the studied variables compared with regular volleyball training.