Primary Hyperparathyroidism due to Parathyroid Adenoma in Children and Adolescents.

OBJECTIVE: In contrast to adults, primary hyperparathyroidism (PHPT) in children and adolescents is a rare endocrine disorder. METHODS: A retrospective review of PHPT cases between 2005 and 2022 from a single tertiary university medical center, including clinical signs and symptoms, laboratory findings, radiological evaluation, treatment, and postoperative complications. RESULTS: Ten children (mean age at diagnosis 16.3 ± 1.3 years) were diagnosed with PHPT. All patients were in late pubertal stages without sex predominance and 8 were symptomatic. Mean calcium level was 13.6 ± 2.5 mg/dL, and mean parathyroid hormone levels were 204.8 ± 163.1 pg/mL. Parathyroid adenoma was confirmed by the postsurgical pathology results. CONCLUSIONS: PHPT in children and adolescents is often symptomatic and more severe than adults. The main cause is single parathyroid adenoma. Associated hypercalcemic syndromes were not found. Patients were cured after surgical removal of the adenoma without significant postoperative complications and no recurrence during 10.4 ± 5.9 years follow-up.

The Genetic Basis of Decathlon Performance: An Exploratory Study.

ABSTRACT: Remmel, L, Ben-Zaken, S, Meckel, Y, Nemet, D, Eliakim, A, and Jürimäe, J. The genetic basis of decathlon performance: an exploratory study. J Strength Cond Res 37(8): 1660-1666, 2023-Decathlon is a combined track and field competition consisting of 10 different events, most of which are anaerobic-type events. Therefore, it is assumed that an anaerobic genetic predisposition might be prevalent among decathletes. Yet, to the best of our knowledge, the genetic basis of decathlon performance had not been studied. Therefore, the aim of this study was to assess the prevalence genetic polymorphisms associated with power performance (AGT, rs699, Met235Thr T/C), speed (ACTN3, rs1815739 C1747T), aerobic endurance (PPARD, rs2016520 T294C), and lactate clearance (MCT1, rs1049434 A1470T) among decathletes. One hundred thirty-seven male track and field athletes (51 sprinters and jumpers, 59 long distance runners, and 27 decathletes) participated in the study. Genomic DNA was extracted from buccal epithelial cells. Genotypes were determined using the Taqman allelic discrimination assay. Decathletes had a higher prevalence of the ACTN3 RR genotype, which is associated with speed ability, and a lower prevalence of the PPARD CC genotype, which is associated with endurance performance compared with long-distance runners. Decathletes had a higher prevalence of the AGT CC genotype associated with strength performance and a higher prevalence of the MCT1 TT genotype, which is associated with improved lactate transport compared with both sprinters and jumpers and long-distance runners. The results suggest that a favorable genetic polymorphism for strength-related capability might be advantageous for decathletes, whereas a genetic makeup favoring aerobic performance is not necessary.

Common genetic basis of ALS patients and soccer players may contribute to disease risk.

OBJECTIVE: The aim of the present study was to determine the prevalence of the ACSL A/G single nucleotide polymorphism among athletes and patients with amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disorder of motor neurons that leads to paralysis and death usually within 3-5 years from onset. Previous epidemiological studies reported a higher risk of ALS among soccer players. The ACSL (long-chain-fatty-acid-CoA ligase 1) gene codes the long-chain fatty-acid-coenzyme A ligase family that plays a key role in lipid biosynthesis and fatty acid oxidation. The ACSL A/G polymorphism is associated with endurance trainability. METHODS: One hundred and seventy-eight ALS patients, 172 athletes (60 soccer players, 112 middle- and long-distance runners), and 111 nonathletic controls participated in the study. Genomic DNA was extracted from blood or buccal cells according to the salting-out procedure. Genotypes were determined using the TaqMan allelic discrimination assay. RESULTS: The prevalence of the ACSL AA genotype was significantly higher among soccer players (35.0%) and ALS patients (39.3%) compared to runners (16.1%) and controls (18.0%). However, ALS GG carriers had a higher mortality rate. CONCLUSION: We postulate that soccer players and ALS patients carry a common genetic predisposition that is related to impaired fatty acid utilization. Moreover, while the A allele might be associated with a genetic predisposition toward ALS, especially among soccer players, the G allele might be associated with disease severity. Further research is needed in order to explore the role of the ACSL rs6552828 polymorphism in ALS.

Reduced Growth Hormone Response to Anaerobic Exercise Among Children With Overweight and Obesity.

ABSTRACT: Hejla, D, Dror, N, Pantanowitz, M, Nemet, D, and Eliakim, A. Reduced growth hormone response to anaerobic exercise among children with overweight and obesity. J Strength Cond Res 36(8): 2194-2197, 2022-The aim of the present study was to examine the effect of an anaerobic exercise test on growth hormone (GH) secretion in children with overweight and obesity compared with children with normal weight. Fifteen children with overweight (body mass index percentile [BMI%ile] ≥85 < 95) and obesity (BMI%ile ≥95) and 10 children with normal weight (BMI%ile >5 < 85) participated in the study. Subjects performed a modification of the Wingate anaerobic test (WAnT), with 10 bouts of 15-second cycling separated by 1 minute of rest. Blood samples for GH and lactate were collected before and 15, 30, 45, and 60 minutes after the beginning of the exercise test. There was a significant increase in GH levels following the modified repeated WAnT in both groups, but the increase in GH levels was significantly greater among the normal weight children compared with those with overweight and obesity ( p < 0.003). Seven of the 10 subjects with normal weight had GH increase above the threshold for GH sufficiency compared with only 2 subjects with overweight and obesity. Growth hormone response to the modified repeated WAnT was significantly reduced among children with overweight and obesity compared with those with normal weight. Anaerobic interval-type training may not be a sufficient exercise alternative to stimulate appropriate GH levels among children with obesity.

Genetic characteristics of competitive swimmers: a review.

A successful swimming performance is a multi-factorial accomplishment, resulting from a complex interaction of physical, biomechanical, physiological and psychological factors, all of which are strongly affected by the special medium of water as well as by genetic factors. The nature of competitive swimming is unique, as most of the competitive events last less than four minutes. Yet training regimens have an endurance nature (many hours and many kilometres of swimming every day), which makes it impossible to classify swimming by definitions of aerobic-type or anaerobic-type events, as in track and field sports. Therefore, genetic variants associated with swimming performance are not necessarily related to metabolic pathways, but rather to blood lactate transport (MCT1), muscle functioning (IGF1 axis), muscle damage (IL6) and others. The current paper reviews the main findings on the leading 12 genetic polymorphisms (located in the ACE, ACTN3, AMPD1, BDKRB2, IGF1, IL6, MCT1, MSTN, NOS3, PPARA, PPARGC1A, and VEGFR2 genes) related to swimming performance, while taking into consideration the unique environment of this sport.

The Effect of Growth Hormone Treatment on Physical Performance Indices in Children With Idiopathic Short Stature.

PURPOSE: To examine the effect of growth hormone (GH) treatment on physical performance in children with idiopathic short stature and normal GH secretion. MATERIALS AND METHODS: A total of 24 children participated in the study (13 GH-treated, 11 non-treated, aged 8-13 y, 11 males and 13 females, Tanner stage 1-2). Participants performed a battery of motor skill performance tests (Eurofit), as well as the Wingate anaerobic test. RESULTS: No statistically significant differences in any of the Eurofit physical fitness test results (eg, 20-m shuttle run 33.0 [15.1] vs 25.1 [21.0] laps in treated and nontreated participants, respectively, P = .25) or the Wingate anaerobic test were found between the groups (eg, peak power 5.0 [2.9] vs 3.9 [2.6] watts/kg in treated and nontreated participants, respectively, P = .2). CONCLUSIONS: Therapeutic usage of exogenous GH for pre and early pubertal children with idiopathic short stature and normal GH secretion was not associated with beneficial effects on physical performance indices. This suggests that the use of GH as a potential performance enhancing agent, in this age group, at least at commonly used doses, is not advantageous.

The Effect of Information Placebo on Physical Activity in Overweight and Obese Children.

PURPOSE: To assess the effect of 1 week of consuming a placebo "energy drink" compared with a week of drinking regular water on daily physical activity in obese children participating in a weight reduction multidisciplinary program. METHODS: Seventeen prepubertal (age = 128.7 [26.6] m) overweight and obese children (7 females and 10 males) participated in the study. Participants received 7 bottles of mineral water per week for 2 weeks. Different types of information were randomly provided regarding the drink consumed in each week: standard (water) versus deliberate positive information (presumed energy drink and placebo). Daily step count was measured using pedometers and compared using paired t test. RESULTS: After consuming the placebo drink, children demonstrated a significantly higher average daily step number (10,452 [4107]) compared with the days they drank water (8168 [2928], P < .005). This difference was attributed mainly to male participants. CONCLUSION: The use of placebo in the form of deliberate positive information was associated with a significant increase in real-life physical activity in overweight and obese children, especially in boys. Positive information may be used to encourage children with obesity to enhance daily physical activity and energy expenditure.

Genetic Basis for the Dominance of Israeli Long-Distance Runners of Ethiopian Origin.

ABSTRACT: Ben-Zaken, S, Meckel, Y, Nemet, D, Kassem, E, and Eliakim, A. Genetic basis for the dominance of Israeli long-distance runners of Ethiopian origin. J Strength Cond Res 35(7): 1885-1896, 2021-Israeli long-distance runners of Ethiopian origin have a major influence on the track and field long-distance record table. The aim of this study was to determine whether genetic characteristics contribute to this long-distance dominance. We assessed polymorphisms in genes related to endurance (PPARD T/C), endurance trainability (ACSL A/G), speed (ACTN3 R/X), strength (AGT T/C), and the recovery from training (MTC1 A/T and IL6 G/C) among top Israeli long-distance runners of Ethiopian origin (n = 37), Israeli non-Ethiopian origin runners of Caucasian origin (n = 76), and Israeli nonathletic controls (n = 55). Israeli runners of Ethiopian origin had a greater frequency of the PPARD CC + PARGC1A Gly/Gly polymorphism, associated with improved endurance performance, compared with Israeli runners of non-Ethiopian origins (24 vs. 3%, respectively, p < 0.01); a lower frequency of the ACSL AA polymorphism, favoring endurance trainability (8 vs. 20%, respectively, p < 0.05); a greater frequency of the ACTN3 RR polymorphism, associated with sprint performance (35 vs. 20%, respectively, p < 0.05); a greater frequency of the MCT1 AA genotype, associated with improved lactate transport (65 vs. 45%, respectively, p < 0.05); and a lower frequency of IL-6 174C carriers, associated with reduced postexercise muscle damage (27 vs. 40%, respectively, p < 0.01). There was no difference in the frequency of AGT T/C gene polymorphism between the long-distance runners of Ethiopian and non-Ethiopian origin. Frequencies of PPARD CC + PARGC1A Gly/Gly, MCT1 AA, IL-6 174C, and AGT polymorphism were significantly favorable among Ethiopian, but not among non-Ethiopian, origin runners compared with controls. Taken together, results suggest that genetically, the dominance of Israeli long-distance runners of Ethiopian origin relates not only to endurance polymorphisms but also to polymorphisms associated with enhanced speed performance and better training recovery ability.

Insulin-like Growth Factor Axis Genetic Score and Sports Excellence.

ABSTRACT: Ben-Zaken, S, Meckel, Y, Nemet, D, and Eliakim, A. Insulin-like growth factor axis genetic score and sports excellence. J Strength Cond Res 35(9): 2421-2426, 2021-It has been suggested that IGF1 polymorphisms associated with circulating IGF1 levels may be linked to elite short-distance running performance. This study assessed genetic score based on 6 polymorphisms related to the Insulin-like growth factor axis (rs7136446, rs35767, rs6220, rs680, rs2854744, and rs1805086) among elite Israeli runners and swimmers. One hundred sixty-one track and field athletes (123 men and 38 women, age 17-50 years) and 94 swimmers (61 men and 33 women, age 16-49 years) participated in the study. Athletes were divided into short-distance runners (SDRs, major event: 100-200-m sprints and jumps, n = 63) and long-distance runners (LDRs, major event: 5,000 m and marathon, n = 98). Swimmers were divided into short-distance swimmers (SDSs, major event: 50-100 m, n = 44) and long-distance swimmers (LDSs, major event: 400-1,500 m, n = 50). Groups were subdivided into top-level and national-level athletes. We calculated the IGF genetic score (IGF-GS) of all the subjects on a 0-100 scale. Top-level SDRs' mean IGF-GS (30.8 ± 11.7) was significantly higher (p < 0.006) compared with national-level SDRs' (20.5 ± 11.3) and top-level SDSs' (19.9 ± 8.5). Subjects with IGF-GS >25 had an increased odds ratio (OR) of being elite-level SDRs (OR: 4.2; 95% confidence interval: 0.68-26.09; p < 0.001). In summary, a combined assessment of 6 single-nucleotide polymorphisms, all known to modulate circulation IGF1 levels, was associated with a higher genetic score among SDRs, emphasizing the importance of the IGF system to land speed sports events but not to swimming events. Whether the IGF-GS may be used for selection of elite-level sprinters in early stages of their athletic career needs to be further investigated.

[MCARDLE'S DISEASE AND PHYSICAL ACTIVITY - A MIXED BLESSING].

INTRODUCTION: McArdle disease (Glycogen storage disease type V) is a myopathy caused by an inherited deficit of muscle glycogen phosphorylase (PYGM). Since glycogen is an important fuel for muscular activity, people with McArdle's disease experience exercise intolerance. Dynamic or static vigorous exercise may lead to rhabdomyolysis, myoglobinuria and renal failure. Although exercise intolerance appears early in childhood, most people with McArdle's disease are diagnosed in the second or third decade of life. People with McArdle's disease tend to avoid exercise, despite its clear beneficial effects on health. As with many chronic diseases, medically supervised exercise with proper nutrition is possible, important, and beneficial to people with McArdle's disease.

The influence of a multidisciplinary intervention program on Achilles tendon structure in children with overweight and obesity.

The effects of childhood obesity on tendon structure and its relation to physical activity are barely known. We aimed to investigate the influence of a 6-month multidisciplinary childhood obesity management program (which included dietary intervention and an exercise program) on Achilles tendon structure in overweight/obese children. Twenty-five overweight/obese children (overweight group) who participated in a 6-month multidisciplinary childhood obesity program, and 27 normal-weight controls were examined for anthropometric measurements and for Achilles tendon structure (using ultrasound tissue characterization to capture a three-dimensional structure of four echo type fibers and the cross-sectional area) at baseline, 3, and 6 months. The BMI of the overweight group significantly decreased from the pre- to the post-intervention period, (p = .002, η2 = .229), yet among the control group, the BMI significantly increased (p = .002, η2 = .222). Interactions (pre-post × group) showed a significant decrease in the prevalence of echo type I and in echo type III fibers and a significant increase in the prevalence of echo type II fibers and in the cross-sectional area along the intervention. No significant changes in echo type fibers were found in the control group along the 6 months.Conclusion: At pre-intervention, the overweight group had significantly "worse" tendon structure, with a lower prevalence of echo type II fiber and a higher prevalence of echo type III fibers compared with the control group. Following the 6-month intervention, the tendon structure of the overweight group was "positively" changed, with reduced echo type III fibers and increased echo type II fibers. What is Known: • Physical activity and weight reduction programs are efficient for obese children. • Obese children tend to suffer orthopedic problems and pain during physical activity. What is New: • Pre-intervention, obese children had 'worse' tendon structure compared to controls. • Following 6-month program, tendon structure of obese children 'positively' changed.

The placebo effect on aerobic fitness test results is preserved following a multidisciplinary intervention program for treating childhood obesity.

BACKGROUND: The aim of the study was to examine the placebo effect on fitness test results in trained and untrained overweight and obese children. METHODS: Twenty pre-pubertal overweight children performed two pairs of progressive treadmill exercise tests before and 12 weeks into a multidisciplinary program for the treatment of childhood obesity. In each test pair, at random order, participants received different types of information regarding a water drink consumed prior to testing-standard information (water) vs deliberate positive information (presumed energy drink, placebo). RESULTS: The intervention led to a significant change (P < .05) in BMI%ile (95.6 ± 4.4 vs 93.6 ± 6.9), % fat (35.4 ± 6.0 vs 31.6 ± 5.8), baseline heart rate (104.2 ± 11.6 vs 94.0 ± 7.0 bpm), total leisure activity score-Godin (9.3 ± 8.8 vs 41.5 ± 15.2), total screen time (6.9 ± 5.8 vs 3.1 ± 1.4 h/d), and a significant improvement in fitness. Following the placebo drink, both groups achieved a significantly higher peak heart rate (untrained: 176.1 ± 13.7 vs 167.5 ± 16.8; trained: 170.7 ± 11.6 vs 166.2 ± 11.4 bpm) and longer running time (untrained: 559.9 ± 151.0 vs 434.4 ± 140.3 seconds; trained: 728.3 ± 177.3 vs 667.1 ± 176.1 seconds). Despite longer exercise duration and higher peak exercise heart rate, average, and peak RPE were lower after the placebo drink (untrained: 12.1 ± 2.3 vs 13.6 ± 2.1; trained:10.0 ± 1.8 vs 11.6 ± 2.1), recovery time was shorter (untrained: 119.2 ± 25.3 vs 133.2 ± 23.7 seconds; trained: 92.6 ± 18.9 vs 102.7 ± 18.3 seconds). The placebo-induced change in running time and peak RPE were significantly greater prior to training. CONCLUSION: The significant information placebo effect is preserved in trained overweight children. Information, as well as other motivating aids and fatigue distractors may be useful in enhancing physical performance in obese children.

Significant effect of information placebo on exercise test results in children with normal weight, overweight and obesity.

AIM: The aim of the study was to examine the effect of information placebo on fitness test results in normal weight, overweight and obese children. METHODS: Twenty-four pre-pubertal children with overweight or obesity and 24 age and maturity-matched normal weight children performed a progressive treadmill exercise test twice. Different types of information were randomly provided regarding a water drink consumed prior to testing; standard (water) vs deliberate positive (presumed energy drink, placebo) information. RESULTS: Following the placebo drink, both groups demonstrated significantly higher peak heart rate (overweight 165.8 ± 16.7 vs 174.2 ± 14.8 bpm and normal weight 177.9 ± 13.6 vs 189.8 ± 12.2 bpm) and longer time to exhaustion (overweight 396.9 ± 161.9 vs 521.5 ± 182.5 seconds; normal weight: 700.1 ± 155.2 vs 893.3 ± 150.1 seconds). Despite longer exercise duration and higher peak heart rate, average and peak rate of perceived exertion were significantly lower after the placebo drink (overweight 14.1 ± 2.5 vs 12.5 ± 2.5; normal weight 12.1 ± 1.4 vs 10.7 ± 1.5), with significantly shorter recovery time (overweight 132.2 ± 28.5 vs 118.4 ± 31.6; normal weight: 106.7 ± 18.6 vs 96.7 ± 17.8 seconds). CONCLUSION: Our results demonstrate a significant effect of information placebo on fitness test results that is unrelated to body weight. Children with obesity may enhance their physical activity levels and energy expenditure if properly encouraged.

Achilles Tendon Tissue Structure in Children with Overweight and Children with Obesity.

Aim: To investigate differences in Achilles tendon structure between children with overweight/obesity and children with normal weight.Methods: Twenty-two children with obesity, 10 children with overweight, and 44 children with normal weight participated in the study. BMI% was calculated. The Achilles tendon was examined using ultrasound tissue characterization (UTC) imaging to capture a three-dimensional structure of four echo-type fibers and a cross-sectional area.Results: A significantly higher percentile of echo-types II, a lower percentile of echo-types III and IV, and a lower cross-sectional area were found for children with normal weight compared with children with overweight/obesity (p < .05). Following a piecewise linear regression model according to tendon structure, a BMI percentile of 75% was found to be the most accurate cutoff point of the children into the "unaffected" (BMI% <75%) and "affected" tendon structure groups (BMI% ≥ 75%), as the children with BMI%≥75% already had an Achilles tendon structure similar to that of the children with overweight/obesity.Conclusions: Tendon integrity as examined with UTC differs between children with obesity and children with normal weight. Children with a BMI percentile of ≥75 already demonstrate a different tendon structure pattern compared with children with BMI percentile of <75. This may put children with obesity at a greater risk of injury and should be addressed when applying an exercise program for children with overweight/obesity.

Attenuation of Lower Body Acceleration in Overweight and Healthy-Weight Children During Running.

This study aimed to identify differences in ground impact shock attenuation between overweight and healthy-weight children during running. Twenty overweight children aged 8.4 (1.1) years and 12 healthy-weight children aged 10.7 (1.3) years ran on a treadmill (120% of baseline speed) while wearing 2 inertial sensors located on their distal tibia and lower back (L3). Peak acceleration attenuation coefficient at foot contact and transfer function of the acceleration were calculated. Peak positive acceleration values were not significantly different between the overweight children and healthy-weight children (3.98 [1.17] g and 3.71 [0.84] g, respectively, P = .49). Children with healthy weight demonstrated significant greater attenuation as evident by greater peak acceleration attenuation coefficient (35.4 [19.3] and 11.9 [27.3], respectively, P < .05) and lower transfer function of the acceleration values (-3.8 [1.9] and -1.2 [1.5], respectively, P < .05). Despite the nonsignificant differences between groups in tibia acceleration at foot-ground impact that was found in the current study, the shock absorption of overweight children was reduced compared with their healthy-weight counterparts.

The effect of placebo on endurance capacity in normal weight children - a randomized trial.

BACKGROUND: The aim of the study was to examine the influence of the placebo effect on the endurance capacity results in normal weight children. METHODS: Twenty-four pre-pubertal normal-weight children aged 6-13 years participated in the study. Subjects underwent anthropometric measurements (weight, height, BMI percentile, and fat percentage), a progressive treadmill exercise test to evaluate endurance capacity, and filled habitual activity questionnaire. The participants were examined twice, in a random order, with each child being compared to him/herself. Different types of information were provided regarding a water drink consumed prior to testing- standard information (water) vs. deliberate positive information (presumed energy drink, placebo). RESULTS: Following the placebo drink, children demonstrated significantly higher peak pulse (177.9 ± 13.6 vs. 189.8 ± 12.2 bpm), higher stage achieved and longer time of exercise to exhaustion (700.1 ± 155.2 vs. 893.3 ± 150.1 s). Although the exercise duration was longer, stage and heart rate achieved were higher, the reported average, and peak rate of perceived exertion (RPE) were significantly lower for the placebo (18.3 ± 1.4 vs 16.2 ± 1.5). Although the effort was higher while drinking placebo (longer run, higher exercise phase, higher heart rate), recovery time was significantly shorter. The reported differences were not associated with order of tests, age, gender or child activity level. CONCLUSION: Our results demonstrate a significant information placebo effect on children's endurance capacity test results. This highlights the possible role of positive information (placebo) in trying to encourage physical activity in children. Whether this effect could be applied to longer-term interventions has yet to be tested. TRIAL REGISTRATION: ClinicalTrial.gov identifier: NCT03165604 , Registered May 24, 2017.

Expert's Choice: 2018's Most Exciting Research in the Field of Pediatric Exercise Science.

This commentary highlights 23 noteworthy publications from 2018, selected by leading scientists in pediatric exercise science. These publications have been deemed as significant or exciting in the field as they (a) reveal a new mechanism, (b) highlight a new measurement tool, (c) discuss a new concept or interpretation/application of an existing concept, or (d) describe a new therapeutic approach or clinical tool in youth. In some cases, findings in adults are highlighted, as they may have important implications in youth. The selected publications span the field of pediatric exercise science, specifically focusing on: aerobic exercise and training; neuromuscular physiology, exercise, and training; endocrinology and exercise; resistance training; physical activity and bone strength; growth, maturation, and exercise; physical activity and cognition; childhood obesity, physical activity, and exercise; pulmonary physiology or diseases, exercise, and training; immunology and exercise; cardiovascular physiology and disease; and physical activity, inactivity, and health.

Rapid Weight Loss in Competitive Judo and Taekwondo Athletes: Attitudes and Practices of Coaches and Trainers.

Fasting, skipping meals, and dehydration are common methods of rapid weight loss used prior to competition in weight category sports. This study examines coaches' attitudes, perceptions, and practices regarding rapid weight loss among judo and taekwondo athletes. A convenience sample of experienced coaches and trainers (n = 68) completed structured questionnaires. Participants in this study were 33.8 ± 9.3 years old; 57 were males and 11 were females; and 59% were certified coaches, with 71% reporting over 20 years of involvement in sports and 68% having more than 10 years of teaching experience. The majority (90%) reported that they usually supervised athletes through the weight loss process. Interventions for weight loss began at 12.7 ± 1.9 years of age, with a recommended precompetition weight loss duration of 16.2 ± 8.2 days and an average reduction of 1.5 ± 0.7 kg. The majority of the responders (92%) recommended that their athletes practice gradual weight loss methods using a combination of dehydration or increased physical activity (80.3%), sweat suits (50.8%), restricted fluid intake (39.3%), training in heated rooms (27%), and sauna (26.2%). Recommendations of spitting (27.8%) or using laxatives, diuretics, diet pills, or vomiting (21.3%) were also reported. Coaches and trainers often encouraged athletes to cut weight before competition. The methods recommended are potentially harmful with severe health risks, including compromised nutritional status and diminished athletic performance. This is of particular concern in young athletes who are still growing and developing physically. Enhancing knowledge and awareness for coaches, athletes, and parents regarding potential dangers, along with improved nutrition education, is critical for reducing the magnitude and misuse of rapid weight loss methods.

Genetic Variability Among Power Athletes: The Stronger vs. the Faster.

Ben-Zaken, S, Eliakim, A, Nemet, D, and Meckel, Y. Genetic variability among power athletes: the stronger vs. the faster. J Strength Cond Res XX(X): 000-000, 2019-Athletic events can be divided into "aerobic-type events" or "anaerobic-type events" based on energy usage. Power, speed, and strength are also used to specify sports subtypes. Weightlifters (WLs), sprinters, and jumpers feature high-intensity efforts lasting a few seconds. However, their performance requires different proportions of power, speed, and strength. The aim of the current study was to examine genetic differences between subtypes of anaerobic athletes in 3 genetic variants: ACTN3 R577X, which is associated with muscle contractions; AGT Met235Thr which is associated with muscle growth; and PPARD T/C, which is associated with aerobic capacity. Seventy-one sprinters and jumpers (S/J), 54 WLs, and 86 controls participated in the study. Genomic DNA was extracted from peripheral blood using a standard protocol. Genotypes were determined using a TaqMan allelic discrimination assay. The ACTN3 RR genotype frequency was significantly higher among S/J (39.4%) compared with WLs (22.2%) and controls (18.6%). The AGT Thr-Thr genotype frequency was significantly higher among WLs (25.9%) compared with S/J (4.2%) and controls (12.8%). PPARD T294C genotype frequencies did not differ between groups. The results suggest that there may be a specific genetic makeup enabling an athlete to excel in speed-oriented events (sprints), rather than in strength-oriented events (weightlifting).

Endocrinology and Pediatric Exercise Science-The Year That Was 2017.

The Pediatric Exercise Science "Year That Was" section aims to highlight the most important (to the author's opinion) manuscripts that were published in 2017 in the field of endocrinology and pediatric exercise science. This year's selection includes studies showing that 1) in pubertal swimmers, there is a decrease in insulin-like growth factor-1 (IGF-I) and IGF-binding protein-3 (IGFBP-3) during intense training (a catabolic-type hormonal response) with an anabolic "rebound" characterized by a significant increase of these growth factors during training tapering down. Moreover, it was shown that changes of IGF-I and IGFBP-3 paralleled changes in peak and average force but not with endurance properties, showing decreases during intense training and increases during tapering; 2) a meta-analysis showing that growth hormone administration elicits significant changes in body composition and possible limited effect on anaerobic performance but does not increase either muscle strength or aerobic exercise capacity in healthy, young subjects; and 3) short-term exercise intervention can prevent the development of polycystic ovary syndrome in a dose-dependent manner in letrozole-induced polycystic ovary syndrome rat model with high-intensity exercise being most effective. The implication of these studies to the pediatric population, their importance, and the new research avenues that were opened by these studies is emphasized.