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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.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.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.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.

Background: Previous research has suggested a correlation between consumption of artificial sweeteners, a paradoxical increase in weight and elevated prevalence of the metabolic syndrome. Our aim was to assess whether consumption of artificial sweeteners impacts the intrinsic hormonal profile in a different manner than consumption of sugar, thus contributing to a secondary increase in caloric consumption.Methods: A cross over, double blind research including 12 young, healthy males. Each participant was randomly assigned to drink a sweetened beverage containing either 50g glucose or 0.166g saccharin. Plasma glucose, insulin, adrenaline, noradrenalin, cortisol, leptin, dopamine, insulin-like growth factor-1 (IGF-1) and growth hormone (GH) levels were sampled before and during the 3 hours after ingestion and dietary intake was assessed for 24 hours.Results: Plasma glucose and insulin levels were significantly higher, after ingestion of the glucose beverage compared to the artificially sweetened beverage. Plasma GH and noradrenaline levels were higher 180 minutes post glucose ingestion. No significant differences were found in the plasma levels of cortisol, leptin, IGF-1 adrenaline and dopamine, following glucose or saccharin ingestion. There was no difference in the 24 hours intake of total calories, carbohydrates, fat and protein. Conclusion: Consumption of a beverage containing saccharin was followed by a difference in glucose and insulin levels compared to glucose ingestion. No differences in other regulatory hormonal responses as well as in the 24h dietary consumption were noted. Larger prospective studies are required to evaluate the influence of artificial sweeteners on the risk of developing obesity and metabolic complications.

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 (p0.006) compared with national-level SDRs' (20.5 ± 11.3) and top-level SDSs' (19.9 ± 8.5). Subjects with IGF-GS25 had an increased odds ratio (OR) of being elite-level SDRs (OR: 4.2; 95% confidence interval: 0.68-26.09; p0.001). 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.

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.

Extra-time (ET) of 30 minutes is played if football match scores are level after 90 minutes in tournament knockout play. The demanding schedule of these tournaments along with possible ET matches in the knockout stages significantly increase players’ overload and injury risk. Present study aimed to determine whether ET during major football national team tournaments contributes to the game outcome. Data on the percentage of elimination matches that needed ET, and the percentage of ET matches that eventually required shootouts were retrieved. Over the years, increased number of participating teams lead to increased number of knockout games, and more knockout games needed ET (13% until 1978, 33% from 1982, in FIFA World Cup). In a significant percentage of matches, the ET itself did not determine the winning team, and the majority of ET matches winners were determined by shootouts (FIFA World Cup since 1982: 60.8%; UEFA European championship: 61.3%; Copa America: 92%). The purpose of playing ET is to make a fair game outcome, and not leave the winning decision for shootouts. However, since in most matches ET does not determine the winner, while significantly increasing the player’s overload and injury susceptibility, the need for ET mandates rethinking.

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.

Decathlon is a combined track and field competition, consisting of ten, mainly anaerobic events. Insulin-like growth factor-I (IGF1) axis plays a pivotal role in athletes' structural and functional muscle adaptation to exercise training, and in their competitive performance. Based on the great demand for speed physiological characteristics among decathlon athletes, the aim of this study was to assess the prevalence of IGF genetic polymorphisms among decathletes, to present an optimal genetic profile for enhancing performance.The participants included 151 male athletes and 75 male non-athletic controls from Israel and Estonia. Athletes were divided into four groups, according to the field of expertise: (a) 40 sprinters and long jumpers; (b) 40 middle distance runners; (c) 44 Weightlifters; and (d) 27 decathletes. Genomic DNA was extracted from the participants' buccal epithelial cells using standard protocol and then analyzed for IGF1 axis related genetic polymorphism using the allelic discrimination assay.A significantly higher prevalence of the IGF1 rs35767 TT genotype was found among decathletes compared to the other athletes, as well as a lower prevalence of the IGF1 rs7136446 GG genotype, a higher prevalence of the IGF1R rs1464430 AA genotype, and a higher prevalence of the IGF2 rs680 GG genotype. Moreover, among the decathletes, carriers of the IGF1 rs7136446 GG genotype achieved higher decathlon scores compared to A-allele carriers.The findings of this study suggest a potential beneficial role for some IGF-axis polymorphisms (mainly the IGF1 1245 TT and the IGF2 GG) among decathletes, both of which are associated with improved speed performance.

The present study examined whether background music improves aerobic and anaerobic performance in overweight children. Eleven participants (14.6±1.5 yrs, BMI%: 94.3±6.5) performed aerobic (20m Shuttle Run) and anaerobic (repeated sprint test – RST) field tests. Ten participants (12.0±2.1 yrs, BMI%:97.4±1.6) performed aerobic (treadmill running) and anaerobic (Wingate Anaerobic Test – WAnT) laboratory tests. Treadmill running time was significantly longer with, compared to without, music (11.9±1.5 versus 10.6±2.2 min, respectively; p

The aim of the study was to examine the effect of Newcomb ball (also known by the name of catchball) training on the physical fitness of women at midlife. One hundred and eighteen women, aged 29 - 45 yrs, were assigned to an experimental group (EG) or a control group (CG), and completed two similar sets of tests before and after seven months of training. The EG performed two Newcomb ball training sessions per week that included technical and tactical drills with and without the ball, small sided games and full games at different variations. The CG remained non-active throughout the seven months. Leg power, arm power, agility, speed, and aerobic scores were significantly higher for the EG compared to the CG at baseline (p p p < 0.05), were found for the CG in any of the other fitness variables. The findings indicate that amateur Newcomb ball training can be used as an efficient and enjoyable tool for fitness development among midlife women.

The main aim of the study was to investigate the differences in repeated sprint ability of first- compared to second-division referees at the beginning and in the middle of the soccer season. Twenty-seven main and 51 assistant referees, from the first (age 36.2 ± 5.3) and the second (age 28.8 ± 3.9) soccer divisions, performed two fitness tests—at the beginning and at mid-season, consisting of a repeated sprint test of 6 × 40 m and 5 × 30 m sprints for the referees and assistant referees, respectively. While no differences were found among the first division’s main referees, significant improvement ( p

Objectives: Soccer is a complex sport in which players are required to perform variety of aerobic and anaerobic activities. The purpose of the study was to explore aerobic (PPARD CC) and anaerobic ...

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%

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.

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.

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).

BackgroundA structured transition process for young adults with chronic medical conditions from pediatric to adult clinics is strongly promoted. However, the most appropriate transition model has not yet been determined. This study evaluated the effect of a “combined team” Endocrinology Transition Clinic model, including a joint meeting with the patient and pediatric and adult endocrinologists, regarding medical treatment, adherence to follow-up and patient satisfaction with the process.MethodsClinical and demographic data of patients admitted to the Endocrinology Transition Clinic were collected. The clinical impact of the transition meeting was evaluated based on treatment modifications and patient adherence to follow-up. Patient satisfaction was evaluated using a questionnaire.ResultsFrom September 2014 through November 2018, 107 patients attended the Endocrinology Transition Clinic, 85.0% were females, mean age 19.7 ± 2.2 years (range 16–29), 97.2% were unmarried. The most common endocrine disorders were obesity (41.1%), Hashimoto’s thyroiditis (41.1%) and ovarian hyperandrogenism (38.3%). The Transition Clinic visit modified treatment and/or evaluation for 48 (44.8%) patients. Adherence to follow-up in the adult clinic was 82.9% and was not associated with gender (p = 0.366), ethnicity (p = 0.725), age at transition (p = 0.479) or obesity (p = 0.375). Overall satisfaction reported by 65/85 patients was high (86.8%), although higher among patients who were adherent to follow-up (89.4% vs. 65.6%, p = 0.006).ConclusionsThe “combined team” transition model in endocrinology requires relatively few resources and has considerable clinical impact, high adherence to follow-up and high patient satisfaction rate. Implementing this model at the interface of pediatric and adult endocrinology units, and possibly in other medical fields, is feasible and efficient.

Attention-deficit/hyperactivity disorder (ADHD) is typically a chronic, often lifelong condition. Data suggest that ADHD itself and its treatment may be associated with dysregulated growth, including height and BMI. The reason for this association is yet unknown. The objective of this study was to examine differences in growth hormone (GH) response to exercise between children who had received a diagnosis of ADHD and age- and gender-matched controls. We reasoned that the normal increase in circulating GH seen in response to exercise would be blunted in children with ADHD.We recruited 13 treatment-naïve children with newly diagnosed ADHD and 14 age-matched controls (all male) and measured GH response to an exercise test in which the work was scaled to each subject's physical capability.There was no difference in the peak heart rate achieved during exercise between controls and ADHD participants (196.6 ± 1.5 vs. 196.5 ± 2.1 bpm, respectively) and lactate response to exercise (53.8 ± 5.0 vs. 47.9 ± 3.8 mg/dl, respectively). After exercise, GH increased significantly in the control subjects (p 0.005), while GH responses were substantially blunted in the ADHD group (p = NS) even though the work performed did not differ from controls.Our data suggest that GH excretion after exercise challenge in children with ADHD is impaired. This can be detected using a minimally invasive, nonpharmacologic challenge and may link ADHD with growth impairment in some children.NCT00945971.

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.

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] ≥8595) and obesity (BMI%ile ≥95) and 10 children with normal weight (BMI%ile585) 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 ( p0.003). 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.

The ACSL A/G polymorphism is associated with endurance trainability. Previous studies have demonstrated that homozygotes of the minor AA allele had a reduced maximal oxygen consumption response to training compared to the common GG allele homozygotes, and that the ACSL A/G single nucleotide polymorphism explained 6.1% of the variance in the VO2max response to endurance training. The contribution of ACSL single nucleotide polymorphism to endurance trainability was shown in nonathletes, however, its potential role in professional athletes is not clear. Moreover, the genetic basis to anaerobic trainability is even less studied. Therefore, the aim of the present study was to examine the prevalence of ACSL single nucleotide polymorphism among professional Israeli long distance runners (n=59), middle distance runners (n=31), sprinters and jumpers (n=48) and non-athletic controls (n=60). The main finding of the present study was that the ACSL1 AA genotype, previously shown to be associated with reduced endurance trainability, was not higher among sprinters and jumpers (15%) compared to middle- (16%) and long-distance runners (15%). This suggests that in contrast to previous studies indicating that the ACSL1 single nucleotide polymorphism may influence endurance trainability among non-athletic individuals, the role of this polymorphism among professional athletes is still not clear.

Objectives To determine the between-visit reliability of an accelerometer as a measure of lower-extremity impact acceleration at a variety of gait speeds in children. Design Absolute reliability assessment. Methods Ten children with no known gait pathology attended two testing sessions, three weeks apart. A tri-axial accelerometer was fixed to the child’s distal tibia to measure peak positive acceleration responses while walking and running on the treadmill at three different speeds (comfortable walking, threshold walking, and jogging). Reliability of the average and standard deviation Peak Positive Acceleration (avgPPA and sdPPA, respectively) was calculated by intra-class correlation coefficients (ICC) and Minimum Detectable Change (MDC). Results Excellent reliability was indicated with ICC values for avgPPA of 0.90, 0.95, and 0.81 for comfortable walking, threshold walking, and jogging, respectively. Moderate reliability was found for the sdPPA measures. MDC values were calculated to be 18%, 26%, and 23% for comfortable walking, threshold walking, and jogging, respectively, indicating the amount by which an avgPPA value would need to change to ensure that the change is greater than a measurement error. Conclusions An accelerometer attached to the distal tibia is practical for use in a clinical environment to collect lower extremity acceleration data in children. Clinicians can utilise this technique for assessing a change following an intervention, such as biofeedback gait retraining.

Physical education teachers should be able to evaluate exercise intensity objectively as well as subjectively in order to implement the appropriate load during activity sessions. Whereas measuring oxygen uptake or blood lactate level during exercise may be a complicated task in field conditions, monitoring heart rate (HR) values can be a relatively simple procedure when performed outdoors. The aim of this study was to examine the subjective estimation accuracy of HR in different exercises among physical education students. Pre-exercise estimations of HR were collected from 180 students prior to a multi-task activity session. The estimated HR values were then compared with true HR values, which were monitored throughout the session using a portable HR monitor system. A mean significant difference of 13.4% was found between the estimated and actual HRs for all activities. A majority of the students (70%) estimated HR values to be lower than the true values. The most accurate HR estimations were found in extremely easy or in extremely difficult activities, whereas the least accurate estimations were found in moderate-level activities. No significant differences were found in HR estimation accuracy between males and females or between individuals with higher and with lower aerobic fitness. The results indicated that physical education students can estimate their HR responses to a reasonable degree of accuracy, but with most underestimating them compared to the actual values.

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 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.

The aim of the present study was to assess prospectively the effect of pre-season fitness on injury rate during the competitive season among professional soccer players. Thirty-one players participated in the study during two consecutive competitive seasons (2015–16 and 2016–17; a squad of 22 players in each season). During the 6-week pre-season training period (8 training sessions and a friendly match every week, 14–18 training hours/week) there was a significant improvement in VO2 max, a significant increase in ideal and total sprint time and no change in vertical jump, flexibility and repeated sprint-test performance decrement. During the two consecutive seasons, 28 injuries were recorded. Ten injuries were classified as mild (missing 3–7 days of practice/match), 8 as moderate (missing 8–28 days) and 10 as severe (missing >28 days). The rate of match injuries was higher (9.4 per 1000 match hours) compared to practice injuries (4.7 per 1000 training hours). Most injuries were overuse injuries (72%) of the lower limbs (71%). Most of match injuries occurred during the last 15 min of each half. There were no differences in fitness characteristics in the beginning of pre-season training between injured and non-injured players. However, improvements in VO2 max during the pre-season training period were significantly lower among injured players (0.9±5.5%) compared to non-injured players (10.4±6.5%, p

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.

A teacher preparation program for physical education (PE) is typically composed of a number of branches, including sport and exercise sciences, sport pedagogy, and activity classes. The activity classes play a key role in developing content knowledge that can be implemented by PE teachers in their classes. An attempt was made in this preliminary study to examine the use of a genetic score that has the potential to assist consultants/instructors in obtaining relevant information on the aerobic and anaerobic abilities of students enrolled in a PE teacher preparation program, as well as in assigning these students to activity classes included in the program. Participants were 219 PE students (111 males and 108 females; mean age = 20 - 29 yrs.), enrolled in a PE teacher preparation program at The Academic College at Wingate. Genomic DNA was extracted from peripheral bloodsamples. Genotyping of the ACTN3R/X and ACE I/D polymorphisms was performed using polymerase chain reaction (PCR). Two polygenetic scores were computed: Power Genetic Distance Score (PGDS2) and Endurance Genetic Distance Score (EGDS2). The main finding that emerged from our study was that both the male and female PE students were genetically predisposed toward aerobic skill rather than toward anaerobic skill: the students’ mean EGDS2 (52.6 + 23.0) was significantly higher compared to their mean PGDS2 (36.3 + 21.9) (p

Previous studies have shown that the IGF1 polymorphism is associated with greater muscle mass and improved power athletic ability, but very little is known about the IGF2 polymorphism and athletic performance.The aim of the present study was to assess the frequency distribution of the IGF2 rs680 polymorphism among Israeli athletes.185 short- (n=72) and long-distance (n=113) runners, 94 short- (n=44) and long-distance (n=50) swimmers, 54 weight lifters and 111 controls participated in the study. Genomic DNA was extracted from peripheral EDTA treated anti-coagulated blood using a standard protocol. Genotyping of the IGF2 A/G polymorphism (rs680) was performed using allelic discrimination assay.The frequency of IGF2 (rs680) G allele carriers was significantly greater among top compared to national-level track and field sprinters and jumpers (p0.05). The IGF2 (rs680) GG genotype frequency was significantly greater among track and field sprinters and jumpers compared to weight lifters p0.02), and among top-level sprinters and jumpers compared to top-level weight lifters p0.01). There were no statistically significant differences in the IGF2 (rs680) GG genotype frequency among endurance athletes and between the swimmers and the other sports disciplines and the controls.While a single polymorphism cannot determine athletic success or failure, the findings of the present study suggest a potential importance of the IGF2 polymorphism, mainly regarding speed sport performance.

To investigate the influence of a weight-reduction program with locomotion-emphasis on improving biomechanical characteristics of children who are obese (OW).Ten children who are OW participated in a 6-month multidisciplinary childhood obesity management program (GRP1); another 10 children who are OW participated in the same multidisciplinary childhood obesity management program with additional locomotion-emphasis exercises for improving biomechanical characteristics (GRP2); and 10 control children who are OW with no intervention program. Outcomes were anthropometric measurements and temporal and foot pressure parameters.GRP2 had significantly improved foot pressure in the different walking/running speeds compared with GRP1. In the temporal parameters, pretests by speed by group interactions were significantly improved for GRP2 compared with GRP1.We found evidence to support beneficial effects of combined dietary and physical activity/locomotion-emphasis exercises on the movement characteristics of children who are OW.

Tibial stress fractures are associated with increased lower extremity loading at initial foot-ground contact, reflected in high peak positive acceleration (>8 g) of the tibia in adults. There is no reported data on peak positive acceleration of the tibia in children during walking and running. The aim of this study was to establish tibial peak positive acceleration responses in children across a range of age and gait speeds. Twenty-four children aged 8.5 ± 1.4 years with no known gait pathology comprised two age groups; Young (7–9 year, n = 12) and Older (10–12 years, n = 12). Wireless Inertial Measurement Unit comprising a tri-axial accelerometer was securely taped to the anteromedial aspect of the distal tibia to measure peak positive acceleration responses while walking and running on the treadmill at 3 different speeds (20% below baseline, baseline, and 20% above baseline). Results showed significant increase in peak positive acceleration with increased gait speed and greater variability in young children compared to older children. The study suggests that ground impact in walking, but not running, is mature by age 7 years. Future studies should explore strategies using peak positive acceleration responses to monitor ground impact during sport activities and its application in gait retraining.

The characterization of activity patterns of overweight and obese (OW) children and adolescents is essential, and should be carried out before they join an exercise training programme and increase their physical activity in order to maintain or reduce body weight.The purpose of this study is to verify whether the biomechanical parameters characterizing frequently used walking and running speeds vary between OW and normal-weight (NW) children. Thirty-one prepubescent OW children (9.9 y ± 1.3) and 10 prepubescent NW children (9.9 y ± 1.2) participated in this study. All participants were evaluated for temporal parameters (e.g. cycle length, cycle time, stance phase time, double support phase time, etc.) and for foot pressure parameters (e.g. contact area, duration of contact, peak pressure, etc.) in six different foot areas, at three walking velocities, and two running velocities. A group effect (p < .05) was found for the peak pressure, duration of contact percentile, maximum force, foot pressure–time inte...

The IL-6 -174G/C single nucleotide polymorphism (SNP) functionally affects IL-6 activity, with the G-allele associated with increased IL-6 levels. The C-allele was found to be associated with exercise-induced skeletal muscle damage. The aim of the present study was to examine the association between the IL-6 -174G/C polymorphism and athletic performance among elite swimmers and runners. The study sample included 180 track and field athletes and 80 swimmers. Track and field athletes were assigned to three sub-groups: long-distance runners, middle-distance runners and short-distance runners. Swimmers were assigned to two subgroups: long-distance swimmers and short-distance swimmers. The control group consisted of 123 non-athletic healthy individuals. Genomic DNA was extracted from peripheral blood following a standard protocol. Genotyping was performed using polymerase chain reaction (PCR). The CC genotype and C-allele frequency were significantly higher in the long-distance swimmers (18 and 43%, respectively) compared to the long-distance runners (3 and 14%, respectively, p < 0.001); middle-distance runners (4 and 22%, respectively, p < 0.001); and controls (5 and 19%, respectively, p < 0.001). In addition, the CC genotype and C-allele frequency were significantly higher (p < 0.001) in long-distance swimmers compared to short-distance swimmers (18 versus 5% and 43 versus 29% for the CC genotype and C-allele frequency, respectively). The higher frequency of the C-allele and CC genotype among long-distance swimmers suggests that the rarity of exercise-associated rhabdomyolysis among swimmers is probably related to other sports-specific or water-related protective mechanisms. It is possible that swimming selection in talented endurance athletes who are C-allele carriers represents an example of genetically-dependent sports selection.

The IGF C-1245T (rs35767) and the myostatin (MSTN) Lys(K)-153Arg(R) genetic polymorphism may influence skeletal muscle phenotypes and athletic performance. Carrying the minor IGF T allele and the myostatin rare R allele was associated with higher circulating IGF-I levels, greater muscle mass and improved performance. The aim of the present study was to assess the combined frequency of the IGF 1245T (rs35767) and MSTN 153Arg(R) polymorphism among Israeli track and field athletes (n=111) and swimmers (n=80).Trackfield athletes were divided to long distance runners (major event 5000m-marathon, n=63) and power athletes (major event 100-200m sprints and long jump, n=48). Swimmers were divided into long-distance swimmers (major event: 400-1500m, n=38), and short-distance swimmers (major event: 50-100m, n=42).Carrying both mutations was significantly higher (p0.05) among long distance runners (LDR, 17%) compared to short distance runners (SDR, 10%), long distance swimmers (LDS, 8%), short distance swimmers (SDS, 2%) and controls (n=111, 7%). Carrying both mutations was significantly higher (p0.05) among LDS compared to SDS (8% versus 2%, p0.05). Among LDR and LDS carriers of both mutations, 40% and 25% were of elite level, respectively. Despite the fact that carrying both mutations among SDR and SDS was not greater than controls, all SDR and SDS carriers were elite athletes.Our finding suggests that carrying both IGF 1245T and MSTN 153Arg(R) polymorphisms may contribute for long distance running success but not necessarily to elite performance. In contrast, although the frequency was not higher than the general population, all carriers of both mutations among short distance runners and swimmers were of elite competitive caliber. Whether evaluation of the IGF 1245T and MSTN 153R polymorphism can be used for sports selection in young athletes needs to be further studied.

The Pediatric Exercise Science Year That Was section aims to highlight the most important (to the author’s opinion) manuscripts that were published in 2016 in the field of endocrinology and pediatric exercise science. This year’s selection includes studies showing that 1) Induction of T4 to T3 conversion by type 2 deiodinase following aerobic exercise in skeletal muscles was associated with concomitant increase in peroxisome proliferatoractivated receptor-γ coactivator-1α, and mitochondrial oxidative capacity and therefore plays an important mechanistic role in the muscle adaptation to exercise training. 2) Hypothyroidism in fetal and early postnatal life was associated with impaired spatial learning and memory and with reduced hippocampal brain-derived neurotrophic factor in male and female rat pups. Forced (treadmill) and voluntary (wheel) exercise alleviated all these biochemical and neuro-cognitive deficits. 3) The relationship between different exercise intensities and carbohydrate requirements to maintain euglycemia at basal insulin levels among adolescent and young adults with Type 1 diabetes are nonlinear but rather inverted- U with no exogenous glucose required to maintain stable glucose level at high-intensity exercise (80%). The implication of these studies to the pediatric population, their importance and the new research avenues that were opened by these studies is emphasized.

The effectiveness of exercise training depends on the training load and on the individual ability to tolerate it, and an imbalance between the two may lead to under- or overtraining. Therefore, efforts have been made to find objective parameters to quantify the balance between training load and the athlete’s tolerance.

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, η

The aim of the study was to estimate the current incidence and the distribution of etiologies of primary ovarian insufficiency (POI) in a nationwide study. The prevalence of POI in young adult women has recently increased, but the data cited for adolescents are more than three decades old.Data regarding females aged21 years diagnosed with POI during the years 2000-2016 were collected from all the pediatric endocrinology units in Israel. POI was defined by at least 4 months of amenorrhea in association with menopausal levels of follicle-stimulating hormone. Iatrogenic cases were excluded.For the 130 females aged21 years included in the study, the distribution of POI etiologies was Turner syndrome/mosaicism in 56 (43%), idiopathic in 35 (27%), and other (developmental, genetic, metabolic, adrenal, and autoimmune) in 39 (30%) females. During the years 2009-2016, compared with 2000-2008, the incidence rate of new POI diagnoses per 100,000 person-years doubled (4.5 vs. 2.0; p value.0001), and incidence rates of idiopathic and other etiologies increased by 2.6 (p value = .008) and 3.0 (p value = .002), respectively. In contrast, the incidence of Turner syndrome was constant (p value = .2). In the age group of 15-21 years, the current incidence of non-Turner POI in adolescents is one per 100,000 person-years.In this nationwide study, the incidence rate of POI in youth aged21 years was one tenth of the rate that is commonly cited. A significant increase in the rate of POI in non-Turner females was observed over the last decade. Contributions of environmental and epigenetic factors should be studied.

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

Previous studies have demonstrated that compared to runners, swimmers carry a higher prevalence of the IL-6 -174C polymorphism and lower single nucleotide polymorphism frequencies of the IGF system.The aim of the present study was to assess the combined frequency of the IL-6 -174G/C and IGFBP3 -202A/C polymorphisms among track and field athletes and swimmers.Track and field athletes were divided into long-distance runners (major event 5000 m-marathon, n = 63) and power athletes (major event 100-200 m sprints and long jump, n = 67). Swimmers were divided into long-distance swimmers (major event: 400-1500 m, n = 50), and short-distance swimmers (major event: 50-100 m, n = 43). All participants had achieved results that ranked them among the top all-time Israeli athletes in their event, and competed at national and/or international level on a regular basis.Carrying both IL-6C and IGFBP3C mutations was significantly greater among long-distance swimmers (LDS - 44%) compared to long distance runners (LDR - 21%, p .01), and among short distance swimmers (SDS - 49%) compared to sprinters and jumpers (S/J - 28%, p .05). Among runners, the prevalence of those not carrying either of the two mutations was significantly higher among LDR (25%) compared to S/J (10%, p .03).The prevalence of carrying both IL-6C and IGFBP3C mutations was significantly higher among the swimmers compared to runners. It is possible that carrying the IGFBP3C polymorphism is required to compensate for the potential genetically non-beneficial effects of a higher IL-6C genotype and an attenuated IGF system among the swimmers.

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 P