Yoav Meckel

Health-related knowledge and preferences in low socio-economic kindergarteners

ObjectiveThe aim of the present study was to determine physical activity (PA) and nutrition knowledge and preferences in low socio-economic status kindergarten children.MethodsFollowing height and weight measurement, 795 low socio-economic status kindergarten children (age 3.8-6.8 y.o) completed a photo-pair knowledge and preferences food and exercise questionnaire.ResultsNo difference was found between nutrition and PA knowledge scores (52.3 ± 0.9 versus 52.6 ± 0.8%, respectively). There was no difference between the nutrition knowledge and preference score (52.3 ± 0.9 versus 50.9 ± 0.9%, respectively). PA preference was significantly higher than knowledge (56.9 ± 1.5 versus 52.6 ± 0.8%, respectively; p < 0.0001). Significant correlations were found between nutrition knowledge and preferences (r = 0.55, p < 0.0001), physical activity knowledge and preferences (r = 0.46, p < 0.0001), and nutrition and PA preferences (r = 0.46, p < 0.001). Nutrition preference scores were significantly lower in overweight compared to normal weight kindergartners 48.1 ± 1.7 versus 52.0 ± 1.0%; p < 0.05). PA knowledge and preference scores were significantly higher among male compared to the female kindergartners (p < 0.001 for both).ConclusionOur data demonstrate diversities in physical activity and nutrition knowledge and preferences among low socio-economic status kindergarten children. These findings may be important for the development of health promotion programs in low socioeconomic kindergarten children.

Relationship Among Repeated Sprint Tests, Aerobic Fitness, and Anaerobic Fitness in Elite Adolescent Soccer Players

Meckel, Y, Machnai, O, and Eliakim, A. Relationship among repeated sprint tests, aerobic fitness, and anaerobic fitness in elite adolescent soccer players. J Strength Cond Res 23(1): 163-169, 2009-The purpose of the study was to examine the relationships among aerobic fitness, anaerobic capacity, and performance indices of 2 different repeated sprint test (RST) protocols in a group of 33 elite adolescent soccer players (age range 16-18 years). All participants performed 4 tests: an aerobic power test (20-m shuttle run), the Wingate Anaerobic Test (WAnT), and 2 different RST protocols (12 × 20 and 6 × 40 m). Significant correlations (p < 0.05) were found between the fastest sprint (r = 0.618), total sprint time (r = 0.709), and performance decrement (PD; r = 0.411) of the 2 RST protocols. A significant negative correlation was found between the PD in the 12 × 20-m RST and calculated peak &OV0312;o2 (r = −0.60, p < 0.05). There was no significant correlation between PD of the 6 × 40-m RST and calculated peak &OV0312;o2 (r = −0.32, p = 0.09). The mean power in the WAnT was significantly correlated with the fastest sprint and the total sprint time of the 6 × 40-m protocol (r = −0.42 and −0.45, respectively) and with the total sprint time of the 12 × 20-m protocol (r = −0.47). There were no correlations between other indices of the WAnT and the 2 RSTs. Despite identical total work, different RST protocols represent different physiological implications. The aerobic system plays a significant role in the maintenance of intensity level during a soccer game, which is characterized by short bursts of activities. Anaerobic performance of repeated brief efforts imposes different physiological stress than a single prolonged activity and, thus, may reflect different physiological capabilities. Therefore, anaerobic testing procedures should consist of specific protocols that mimic the athletes specific sports activity pattern.

The ACE deletion allele is associated with Israeli elite endurance athletes

An Alu insertion (I)/deletion (D) polymorphism in the angiotensin I converting enzyme (ACE) gene has been associated with ACE activity. Opposing effects on elite athletic performance have been proposed for the I and D alleles; while the D allele favours improved endurance ability, the I allele promotes more power‐orientated events. We tested this hypothesis by determining the frequency of ACE ID alleles amongst 121 Israeli top‐level athletes classified by their sporting discipline (marathon runners or sprinters). Genotyping for ACE ID was performed using polymerase chain reaction on DNA from leucocytes. The ACE genotype and allele frequencies were compared with those of 247 healthy individuals. Allele and genotype frequencies differed significantly between the groups. The frequency of the D allele was 0.77 in the marathon runners, 0.66 in the control subjects (P= 0.01) and 0.57 in the sprinters (P= 0.002). The ACE DD genotype was more prevalent among the endurance athletes (0.62) than among the control subjects (0.43, P= 0.004) and the power athletes (0.34, P= 0.004). In the group of elite athletes, the odds ratio of ACE DD genotype being an endurance athlete was 3.26 (95% confidence interval 1.49–7.11), and of ACE II genotype was 0.41 (95% confidence interval 0.14–1.19). We conclude that in Israeli elite marathon runners the frequency of the ACE D allele and ACE DD genotype seems to be higher than in sprinters, suggesting a positive association between the D allele and the likelihood of being an elite endurance athlete in some ethnic groups.

The Effect of a Brief Sprint Interval Exercise on Growth Factors and Inflammatory Mediators

Meckel, Y, Eliakim, A, Seraev, M, Zaldivar, F, Cooper, DM, Sagiv, M, and Nemet, D. The effect of a brief sprint interval exercise on growth factors and inflammatory mediators. J Strength Cond Res 23(1): 225-230, 2009-Exercise training efficiency depends on the intensity, volume, duration, and frequency of training, as well as on the athletes ability to tolerate it. Recent efforts to quantify the effects of aerobic exercise training on hormonal response have suggested that exercise leads to simultaneous changes of antagonistic mediators. The effects of anaerobic exercise on these mediators are not known. Therefore, the aim of the present study was to evaluate the effects of a brief sprint interval session on the balance between anabolic (growth hormone [GH]→ insulin-like growth factor [IGF]-I axis) and catabolic hormones (cortisol), and circulating inflammatory cytokines such as interleukin (IL)-6. Twelve healthy elite junior handball players (17-20 years) participated in the study. Exercise consisted of a 4 × 250-m run on a treadmill, at a constant intensity of 80% of the personal maximal speed. Each run was separated by 3 minutes of rest. Blood samples were collected before, immediately after each 250-m run, and 1 hour after the last run. Exercise led to significant increases in GH (0.3 ± 0.2 to 5.1 ± 2.2 ng·ml−1, p < 0.05), IGF binding protein (IGFBP)-3 (4191 ± 2.48 to 4875 ± 301 ng·ml−1, p < 0.05), IL-6 (1.3 ± 0.2 to 2.1 ± 0.3 pg·ml−1, p < 0.002), testosterone, and testosterone/cortisol ratio, and to a significant decrease in IGFBP-1 levels. Levels of IL-6 remained elevated 1 hour after the end of exercise. Exercise had no significant effects on IGF-I and cortisol levels. Changes in the GH-IGF-I axis and testosterone/cortisol ratio after the brief sprint interval exercise suggested exercise-related anabolic adaptations. The increase in IL-6 may indicate its important role in muscle tissue repair after anaerobic exercise. Changes in the anabolic-catabolic hormonal balance and in inflammatory mediators can be used as an objective tool to gauge the training intensity of different types of anaerobic exercises and training periods.

Human, Environmental & Exercise: The ACE deletion allele is associated with Israeli elite endurance athletes

An Alu insertion (I)/deletion (D) polymorphism in the angiotensin I converting enzyme (ACE) gene has been associated with ACE activity. Opposing effects on elite athletic performance have been proposed for the I and D alleles; while the D allele favours improved endurance ability, the I allele promotes more power‐orientated events. We tested this hypothesis by determining the frequency of ACE ID alleles amongst 121 Israeli top‐level athletes classified by their sporting discipline (marathon runners or sprinters). Genotyping for ACE ID was performed using polymerase chain reaction on DNA from leucocytes. The ACE genotype and allele frequencies were compared with those of 247 healthy individuals. Allele and genotype frequencies differed significantly between the groups. The frequency of the D allele was 0.77 in the marathon runners, 0.66 in the control subjects (P= 0.01) and 0.57 in the sprinters (P= 0.002). The ACE DD genotype was more prevalent among the endurance athletes (0.62) than among the control subjects (0.43, P= 0.004) and the power athletes (0.34, P= 0.004). In the group of elite athletes, the odds ratio of ACE DD genotype being an endurance athlete was 3.26 (95% confidence interval 1.49–7.11), and of ACE II genotype was 0.41 (95% confidence interval 0.14–1.19). We conclude that in Israeli elite marathon runners the frequency of the ACE D allele and ACE DD genotype seems to be higher than in sprinters, suggesting a positive association between the D allele and the likelihood of being an elite endurance athlete in some ethnic groups.

Hormonal and inflammatory responses to different types of sprint interval training.

Meckel, Y, Nemet, D, Bar-Sela, S, Radom-Aizik, S, Cooper, DM, Sagiv, M, and Eliakim, A. Hormonal and inflammatory responses to different types of sprint interval training. J Strength Cond Res 25(8): 2161-2169, 2011—We evaluated the effect of different types of sprint interval sessions on the balance between anabolic and catabolic hormones and circulating inflammatory cytokines. Twelve healthy elite junior handball players (17-25 years) participated in the study. Exercise consisted of increasing distance (100 m, 200 m, 300 m, 400 m) and decreasing distance (400 m, 300 m, 200 m, 100 m) sprint interval runs on a treadmill (at random order), at a constant work rate of 80% of the personal maximal speed (calculated from the maximal speed of a 100 m run). The total rest period between the runs in the different interval sessions were similar. Blood samples were collected before, after each run, and after 1-hour recovery. Both types of sprint interval trainings led to a significant (p < 0.05) increase in lactate and the anabolic factors growth hormone, insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), and testosterone levels. Both types of sprint interval sessions led to a significant (p < 0.05) increase in the circulating pro- and anti-inflammatory mediators IL-1, IL-6, and IL1ra. IL-6 remained elevated in both sessions after 1-hour recovery. Area under the curve was significantly greater (p < 0.05) for lactate and growth hormone (GH) in the decreasing distance session. In contrast, rate of perceived exertion was higher in the increasing distance session, but this difference was not statistically significant (p = 0.07). Changes in anabolic-catabolic hormones and inflammatory mediators can be used to gauge the training intensity of anaerobic-type exercise. Changes in the GH-IGF-I axis and testosterone level suggest exercise-related anabolic adaptations. Increases in inflammatory mediators may indicate their important role in muscle tissue repair after anaerobic exercise. The decreasing distance interval was associated with a greater metabolic (lactate) and anabolic (GH) response but not with a higher rate of perceived exertion. Coaches and athletes should be aware of these differences, and as a result, of a need for specific recovery adaptations after different interval training protocols.

Estimation of %VO2 reserve from heart rate during arm exercise and running.

Abstract The purpose of the present investigation was to examine the relationship between the percent heart rate reserve (%HRR) in arm exercise and the corresponding percent oxygen uptake (V˙O2) reserve, and to compare this relationship to that occurring in running. Fourteen male physical education students took part in the study. Each subject performed a maximal running exercise test and a maximal arm cycling test. The subjects also performed three submaximal exercise bouts (in both exercise modes) at 30%, 60% and 80% of their HRR. The subjects were monitored for their heart rate (HR) at rest, maximal HR (HRmax), HR at submaximal work loads, maximal V˙O2 (V˙O2max), V˙O2 at rest and V˙O2 at submaximal loads. For each subject, load and exercise mode, %HRR and %V˙O2 reserve were calculated (from HRmax and V˙O2max as measured during running and arm cycling) and the relationship between the two was evaluated. The main finding of the present investigation is that the prediction of %V˙O2 reserve in arm cycling from %HRR is grossly overestimated when calculated from HRmax and V˙O2max measured during running. The prediction is better but still overestimated when calculated from HRmax and V˙O2max measured during arm cycling. The findings indicate a better prediction of %V˙O2 reserve from %HRR for running than for arm exercise. These findings should be taken into consideration when prescribing the target HR for arm training.

Immediate post-exercise energy intake and macronutrient preferences in normal weight and overweight pre-pubertal children

OBJECTIVE To examine the immediate effect of three different types of popular exercise activities on food intake and preferences in normal weight and overweight children. SUBJECTS AND METHODS Forty-four (22 overweight) age and gender matched, pre-pubertal children participated in four separate visits. All performed three typical, 45 min, aerobic, indoor resistance and swimming exercise sessions and a control visit (no exercise). A similar buffet lunch was served immediately after each visit to both groups. The total energy intake and relative consumption of carbohydrates, fat and protein were recorded. RESULTS In the normal weight children, total energy intake was reduced following exercise. This difference reached statistical significance only following the resistance-type exercise (14.0 + or - 1.4 [58.6 + or - 5.9] versus 19.4 + or - 1.7 [81.2 + or - 7.1] kcal/kg [kJ/ kg], in resistance exercise and control, respectively; p<0.008). The different types of exercise were associated with increased relative consumption of carbohydrate and decreased consumption of fat. In contrast, in the overweight children, total energy intake was increased following exercise. This increase reached statistical significance following the swimming exercise session (23.0 + or - 2.4 [96.3 + or - 10.0] versus 18.5 + or - 1.5 [77.4 + or - 6.3] kcal/kg [kJ/kg] in swimming and control, respectively; p<0.02). All types of exercise lead to a significant increase in the relative consumption of proteins in the overweight children. Finally, the total energy intake was significantly greater in the overweight children following the control (i.e., no exercise), and all types of exercise sessions. After normalization of the total energy intake to body mass, this difference remained significant only following the swimming practice (23.0 + or - 2.4 [96.3 + or - 10.0] versus 15.9 + or - 1.6 [66.6 + or - 6.7] kcal/kg [kJ/kg] in overweight and normal weight, respectively; p<0.04). CONCLUSIONS Understanding the complicated relationship between exercise, appetite, and food choices may help us to optimize exercise interventions for this unique population, and to select the best exercise protocols to achieve a desired energy balance. Food intake and preferences in response to acute exercise are different in normal weight and obese children.

Is there an interaction between PPARD T294C and PPARGC1A Gly482Ser polymorphisms and human endurance performance

Functional Gly482Ser (rs8192678) and T294C (rs2016520) polymorphisms in the peroxisome proliferator‐activated receptor γ coactivator‐1 (PPARGC1A) and peroxisome proliferator‐activated receptor δ (PPARD) genes, respectively, have been associated with mRNA and/or protein activity. The aim of this study was to determine their frequency distribution among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy control subjects. There were no differences between the endurance athletes, the sprinters and the control group across the PPARD T294C genotypes (P= 0.62). Similarly, no statistical differences were found between the subgroups of elite‐level endurance athletes (those who had represented Israel in a world track and field championship or in the Olympic Games) and national‐level endurance athletes (P= 0.3), or between elite‐level and national‐level sprinters (P= 0.9). However, a combined influence of these two polymorphisms on endurance performance was found. The PPARD CC +PPARGC1A Gly/Gly genotypes were more frequently found in the elite endurance athletes than in national‐level endurance athletes (P < 0.000). In the cohort of endurance athletes, the odds ratio of the ‘optimal genotype’ for endurance athletes (PPARD CC +PPARGC1A Gly/Gly +PPARGC1A Gly/Ser) being an elite‐level athlete was 8.32 (95% confidence interval 2.2–31.4). In conclusion, the present study suggests that PPARD T294C is not associated with endurance performance. However, a higher frequency of the PPARGC1A Gly/Gly +PPARD CC genotype is associated with elite‐level endurance athletes.

Is there an ACE ID-ACTN3 R577X polymorphisms interaction that influences sprint performance?

Functional R577X (rs.1815739) and ID (rs.5186) polymorphisms in the alpha-actinin-3 ( ACTN3) and the angiotensin converting enzyme (ACE) genes, respectively, have been associated with sprint performance. The aim of this study was to determine their effect on sprint performance among 81 Israeli sprinters and 240 healthy controls. Results revealed that the ACE II genotype+ ACTN3 R allele (P=0.003 for sprinters vs. controls), and the ACTN3 RR genotype +ACE I allele (P=0.001 for sprinters vs. controls) might be the genotype for sprinters. In the whole cohort the probability of ACTN3 RR genotype+ ACE I allele being a sprinter (odds ratio 2.67, 95% confidence interval 1.45-4.93) and of ACE II genotype+ ACTN3 R allele being a sprinter (odds ratio 3.57, 95% confidence interval 1.78-7.15) was significantly higher than that in the controls. In conclusion, the above data suggest that ACE ID/ ACTN3 R577X genotype combination is associated with sprint ability. However, ACE ID/ ACTN3 R577X genotype combination is not related to the level of performance.