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Change in muscle glycogen between rapid weight loss and recovery. Muscle glycogen was measured before (BL) and after rapid weight loss (R0) at 2 h (R2), 4 h (R4), and 13 h (R13) after initiating meal. Data are presented as means and SD (n = 10). BL, baseline; *p < 0.05 versus BL; †p < 0.05 versus R0; #p < 0.05 versus R2
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Background
Severe rapid weight loss (RWL) induces a decrease in muscle glycogen (mGly). Nevertheless, adequate carbohydrate intake after RWL has not been reported to optimize muscle glycogen following a weigh-in the evening until a wrestling tournament morning. The purpose of this study was to investigate the effect of an overnight high-carbohydrat...
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Citations
... Reaching recommended nutrition thresholds, including an adolescent athlete diet with 50% carbohydrates and water intake hours in advance is exceedingly difficult or even impossible during RWG [55]. For example, muscle glycogen may be unable to reach pre-RWL levels even after a carbohydrate-rich meal [56]. Protein, calcium, and iron are often deficient in adolescents at baseline, further increasing risk for MSK injury during a nutrient deficit [57]. ...
Purpose of review
Adolescent wrestlers undergo intense physical combat. While guidelines are effective in keeping the sport safer, concerns specific to the adolescent wrestler may be missed at primary care visits without knowledge of the unique challenges faced by these athletes. The following review highlights important characteristics of the adolescent wrestler which are of interest to primary care providers.
Recent findings
Recommendations for concussion management are evolving to gradual return-to-sport after physician clearance rather than total sport removal. Prolonged skin-to-skin contact also places athletes at greater risk of dermatologic infections, which often require removal from competition, treatment, and/or coverage. Finally, adolescent nutritional literature recommends limiting pre-match weight loss to 3–5% body weight due to noted kidney damage that may result from larger deficits.
Summary
Adolescent wrestlers are more prone to acute injuries than chronic overuse injuries, with most injuries occurring above the trunk. Primary care providers should consider obtaining imaging to rule out severe injuries or referring to specialist providers.
Current guidelines for skin infections require frequent pre-match skin checks and mandatory waiting periods when certain infections are identified. However, the primary care provider is well-equipped for more in-depth skin examination, discussion of skin hygiene, and appropriate treatment of skin infections.
Athletes attempting to meet lower weight classes may put themselves at risk of acute kidney damage, under-fueling, and eating disorders. Current guidelines attempt to mitigate excessive weight changes in the adolescent wrestler during competition season, but primary care providers should emphasize healthier methods of weight fluctuation and look for indicators of physiological or psychological effects.
... Before the measurements, participants completed weighed dietary records for three separate days, including two training days and one day off. The habitual intakes of energy and macronutrients (carbohydrate, protein and fat) were calculated by the same method as that of previous studies [27,28]. The habitual energy expenditure of the participants was estimated before the experimental trial using a 3-axis accelerometer (Actimarker, Panasonic, Osaka, Japan). ...
Daily muscle glycogen recovery after training is important for athletes. Few studies have reported a continuous change in muscle glycogen for 24 h. We aimed to investigate the changes in carbohydrate intake amount on muscle glycogen recovery for 24 h after exercise using 13C-magnetic resonance spectroscopy (13C-MRS). In this randomized crossover study, eight male participants underwent prolonged high-intensity exercise, and then consumed one of the three carbohydrate meals (5 g/kg body mass (BM)/d, 7 g/kg BM/d, or 10 g/kg BM/d). Glycogen content of thigh muscle was measured using 13C-MRS before, immediately after, and 4 h, 12 h and 24 h after exercise. Muscle glycogen concentration decreased to 29.9 ± 15.9% by exercise. Muscle glycogen recovery 4-12 h after exercise for the 5 g/kg group was significantly lower compared to those for 7 g/kg and 10 g/kg groups (p < 0.05). Muscle glycogen concentration after 24 h recovered to the pre-exercise levels for 7 g/kg and 10 g/kg groups; however, there was a significant difference for the 5 g/kg group (p < 0.05). These results suggest that carbohydrate intake of 5 g/kg BM/d is insufficient for Japanese athletes to recover muscle glycogen stores 24 h after completing a long-term high-intensity exercise.
... Following weigh-in, combat athletes try to renew body fluids, electrolytes, and glycogen in less than 24 h prior to competition but restoration of bodily fluids may take 12-48 h and filling up muscle glycogen depots may take up to 72 h [8]. Indeed, when high-carbohydrate meal of (7.1 g/kg) was ingested after 6% RWL, it was not sufficient to recover muscle glycogen during a 13 h recovery phase in male wrestlers [9], so nutritional timing is another critical aspect of combat sports nutrition. Within the second ACSM stance, it was concluded that RWL practice creates a synergistic, adverse physiologic effect on the body, leaving the wrestler ill-prepared for competition [3]. ...
Background
As combat sports are classified by body mass, many athletes engage in rapid weight loss (RWL) prior to competition so they can gain an advantage over lighter opponents. Following the weigh-in, athletes engage in rapid weight gain (RWG), whereby some athletes have been able to compete up to three weight categories greater than the official division weighed in at.
Results
Although the impact of weight cycling on performance remains equivocal, robust scientific evidence indicates serious acute and chronic negative consequences on physiological and health-related parameters. Still, weight cycling remains highly prevalent in combat sports, and interventions to limit or stop this cultural norm are recommended.
Conclusions
Weigh-ins for combat sports should be transitioned to take place closer to the start of competition. This reduced time and access to engage in RWG will cut down, if not completely prevent, weight cycling. These rule changes that aim to benefit athlete’s health and promote fairness must be made at the international level, which will promote them at those levels below, as well, given qualification protocols.
Depending on the nature of their sports, athletes may be engaged in successive weight loss (WL) and regain, conducing to “weight cycling.” The aims of this paper were to systematically (and meta‐analytically when possible) analyze the post‐WL recovery of (i) body weight and (ii) fat mass; fat‐free mass; and performance and metabolic responses in weight cycling athletes (18–55 years old, body mass index < 30 kg.m ⁻² ). MEDLINE, Embase, and SPORTDiscus databases were explored. The quality and risk of bias of the 74 included studies were assessed using the quality assessment tool for quantitative studies. Thirty‐two studies were eligible for meta‐analyses. Whatever the type of sports or methods used to lose weight, post‐WL body weight does not seem affected compared with pre‐WL. While similar results are observed for fat‐free mass, strength sports athletes (also having longer WL and regain periods) do not seem to fully recover their initial fat mass (ES: −0.39, 95% CI: [−0.77; −0.00], p = 0.048, I ² = 0.0%). Although the methods used by athletes to achieve WL might prevent them from a potential post‐WL fat overshooting, further studies are needed to better understand WL episodes consequences on athletes' performance as well as short‐ and long‐term physical, metabolic, and mental health.
Purpose: to investigate the dynamics of strength training of qualified wrestlers under the influence of an experimental strength training program during the period of weight loss. Material and Methods. A member of the national freestyle wrestling team. took part in the research. The athlete is 20 years old, and has been practicing wrestling for 9 years. The study was conducted during the preparation for the national championship. A training program was developed for qualified wrestlers, which is advisable to use when preparing for competitions in special conditions of weight loss. The experimental program consisted of a strength training program and a body weight loss program with the use of a specially developed diet and drinking regime, and additional use of ergogenic means was also foreseen. In addition, the experimental training program included special training work. Research methods: analysis of scientific and methodological sources; summarizing the practical experience of specialists; pedagogical observations; pedagogical experiment; pedagogical testing; methods of mathematical statistics. Results. During the study period, the tested athlete, despite a significant decrease in his own weight by 6.5 kg (7.4%), managed to maintain the absolute power index in the bench press (100%), increase the result in the squat with a barbell by 2.8%, by 10% in the dead lift and by 10.5% in the standing long jump. Significant positive changes were observed in the study of relative strength indicators. The subject improved by 8.1% in the bench press, 18.8% in the barbell squat, 11.6% in the dead lift, and 19.3% in the long jump. A significant positive dynamic of the special speed strength indicator is observed when the athlete performs a double leg shot during training bouts (t = 9.4; p ˂ 0.01). The study of general and special speed-power endurance also revealed significant positive changes in the tested athlete. The time for performing a set of Cross Fit exercises decreased by 17.6%. Special Endurance coefficientt improved by 10.7%. Conclusions The results of the study showed that the use of an experimental program for training qualified wrestlers for competitions, in the conditions of reducing body weight, during eight weeks, contributed to a significant positive dynamic of the strength general and special preparedness of the athletes.
With applications across chemistry, physics and medicine, nuclear magnetic resonance is a proven, uniquely versatile and powerful spectroscopic technique. The success of NMR and its constant redevelopment means that the literature is vast and wide-ranging. Each chapter in this volume is a distillation of the key recent literature in different areas, covering the spectrum of NMR theory and practice, and including solid-state NMR, solution NMR of small molecules and NMR of living systems. These reports are invaluable both for new researchers wishing to engage with literature for the first time, and for seasoned practitioners, particularly service managers, needing to keep in touch with the ever-expanding ways in which NMR is used.
Aim of this investigation is analysis of relative age effect on success in taekwondo. Research is conducted on sample composed of Youth Olympic games competitors (n=100), both male and female, on Youth Olympic games held 2018. Data composed of birth dates, weight categories and sex were collected. According to the criterion of chronological age, sub-surveys of subjects were formed: a) 2001, and b) 2002. By applying the χ2-squared test, statistically significant differences were found (χ 2 = 9.000; p = 0,0027) between observed and expected frequencies per year of birth. Results showed that 65 % of competitors were born in 2001, and 35 % of them 2002 which means that most participants born in 2001 are potentially up to 12 months older than their opponents born in 2002.