The purpose of this study was to examine the effect of the Ramadan fast on performance capacities, dietary habits, and the daily behavioral patterns in adolescent (14-16-year-old) soccer players. Nineteen male players performed a series of fitness tests before and at the end of Ramadan fast. Caloric intake, physical activity pattern and sleep habits were evaluated during the week before the Ramadan fast and during the last week of the Ramadan fast. The fast resulted in a significant reduction in aerobic capacity [3,000 m run time (mean +/- SD): 812.8 +/- 73.3 s vs. 819.9 +/- 73.4 s, P < 0.001], speed endurance (Sum 6 x 40 m run time: 46.36 +/- 1.36 s vs. 46.73 +/- 1.31 s, P < 0.001, and performance decrement: 9.0 +/- 1.5% vs. 9.5 +/- 1.7%, P < 0.05), and jumping performance (44.8 +/- 4.5 cm vs. 44.0 +/- 4.5 cm, P < 0.05), but had no significant effect on sprint performance (7.38 +/- 0.25 s vs. 7.40 +/- 0.26 s, P = 0.20) or agility (4 x 10 m shuttle run time: 9.53 +/- 0.35 s vs. 9.55 +/- 0.37 s, P = 0.26). Daily intense physical activity was significantly reduced during Ramadan (6.4 +/- 0.2 h/week vs. 4.5 +/- 0.1 h/week, P < 0.005). There were no significant differences in total caloric intake (3,012 +/- 412 kcal/day vs. 3240 +/- 348 kcal/day, P = 0.39) or total daily sleeping hours (8.6 +/- 0.7 h/day vs. 8.6 +/- 0.5 h/day, P = 0.80) between Ramadan and a regular month. The results indicate that Ramadan fasting can lead to a significant decrease in athletic performance capacities. The decrease in performance does not necessarily relate to changes in caloric intake and sleeping hours during the fast.

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.

A common genetic variation in the alpha-actinin-3 ( ACTN3) gene causes a replacement of an arginine (R) with a premature stop codon (X) at amino-acid 577 (rs1815739). While the R allele has been found to be associated with power-oriented performance, the XX genotype may be linked with endurance ability. To test this hypothesis, we studied the distribution of ACTN3 genotypes in 155 Israeli athletes (age=35.9+12.2 years) classified by sport (endurance runners and sprinters) and in 240 sedentary individuals. The sprinters' allele frequencies (AF: R/X=0.7/0.3) and 577RR genotype distribution percentage (GD: RR=52%) differed markedly from those of the endurance athletes (AF: R/X=0.53/0.47, p=0.000007; GD: RR=18%, p=0.00009) and the control group (AF: R/X=0.55/0.45, p=0.0002; GD: RR=27.3%, p=0.000003). A comparison between the top-level and national-level sprinters revealed that the R allele occurs more often in the top-level sprinters. A significantly higher proportion of the XX genotype was observed in endurance athletes (34%) compared with controls (18%, p=0.02) and sprinters (13%, p=0.002). However, top-level and national level endurance athletes had similar allele and genotype frequencies. We conclude that the ACTN3 R allele is associated with top-level sprint performance and the X allele and XX genotypes may not be critical but rather additive to endurance performance.

Music is believed to improve athletic performance. The aim of the present study was to determine the effect of arousing music during warm-up on anaerobic performance in elite national level adolescent volleyball players. Twenty-four players (12 males and 12 females) performed the Wingate Anaerobic Test following a 10-minute warm-up with and without music (two separate occasions, random order). During warm-up with music, mean heart rate was significantly higher. Following the warm-up with music, peak anaerobic power was significantly higher in all volleyball players (10.7 +/- 0.3 vs. 11.1 +/- 0.3 Watts/kg, p < 0.05, without and with music, respectively). Gender did not influence the effect of music on peak anaerobic power. Music had no significant effect on mean anaerobic output or fatigue index in both genders. Music affects warm-up and may have a transient beneficial effect on anaerobic performance.

The effect of HMB supplementation on body composition, fitness, hormonal and inflammatory mediators in elite adolescent volleyball players: A prospective randomized, double-blind, placebo-controlled study The effect of HMB supplementation on body composition, fitness, hormonal and inflammatory mediators in elite adolescent volleyball players: a prospective randomized, double-blind, placebo-controlled study Abstract The use of ergogenic nutritional supplements is becoming inseparable from competitive sports. b-Hydroxyb-Methylbutyric acid (HMB) has recently been suggested to promote fat-free mass (FFM) and strength gains during resistance training in adults. In this prospective randomized, double-blind, placebo-controlled study, we studied the effect of HMB (3 g/day) supplementation on body composition, muscle strength, anaerobic and aerobic capacity, anabolic/catabolic hormones and inflammatory mediators in elite, national team level adolescent volleyball players (13.5-18 years, 14 males, 14 females, Tanner stage 4-5) during the first 7 weeks of the training season. HMB led to a significant greater increase in FFM by skinfold thickness (56.4 ± 10.2 to 56.3 ± 8.6 vs. 59.3 ± 11.3 to 61.6 ± 11.3 kg in the control and HMB group, respectively, p \ 0.001). HMB led to a significant greater increase in both dominant and non-dominant knee flexion isokinetic force/FFM, measured at fast (180°/sec) and slow (60°/sec) angle speeds, but had no significant effect on knee extension and elbow flexion and extension. HMB led to a significant greater increase in peak and mean anaerobic power determined by the Wingate anaerobic test (peak power: 15.5 ± 1.6 to 16.2 ± 1.2 vs. 15.4 ± 1.6 to 17.2 ± 1.2 watts/FFM, mean power: 10.6 ± 0.9 to 10.8 ± 1.1 vs. 10.7 ± 0.8 to 11.8 ± 1.0 watts/FFM in control and HMB group, respectively, p \ 0.01), with no effect on fatigue index. HMB had no significant effect on aerobic fitness or on anabolic (growth hormone, IGF-I, testosterone), catabolic (cortisol) and inflammatory mediators (IL-6 and IL-1 receptor antagonist). HMB supplementation was associated with greater increases in muscle mass, muscle strength and anaerobic properties with no effect on aerobic capacity suggesting some advantage for its use in elite adolescent volleyball players during the initial phases of the training season. These effects were not accompanied by hormonal and inflammatory mediator changes.

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 x 20 and 6 x 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 x 20-m RST and calculated peak VO2(r = -0.60, p < 0.05). There was no significant correlation between PD of the 6 x 40-m RST and calculated peak VO2(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 x 40-m protocol (r = -0.42 and -0.45, respectively) and with the total sprint time of the 12 x 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 athlete's specific sports activity pattern.

Functional Gly482Ser (rs8192678) and G/C (rs4253778) polymorphisms in the Peroxisome proliferator-activated receptor gamma coactivator1 (PPARGC1A) and Peroxisome proliferator-activated receptor alpha (PPARalpha) genes, respectively, have been associated with mRNA and protein activity. The aim of this study was to determine their frequency distribution among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy controls. Results showed that there was a significant difference in PPARGC1A Ser482Gly polymorphism genotype frequencies between endurance athletes and sprinters (P=0.005) as well as between endurance athletes and controls (P=0.0003). However, the sprinters' genotype and allele frequencies were similar to that of the control group. A significantly lower proportion of PPARGC1A Ser482 allele (0.25) was noted for the endurance athletes compared with controls (0.43, P=0.0001). Endurance athletes showed a trend of a higher yet a not significant proportion of the PPARalpha GG genotype compared with sprinters (P=0.051). As we compared between the subgroups of top-level endurance athletes and top-level sprinters, as well as between those of top-level and national-level endurance athletes, we reached more prominent results. In conclusion, our data indicate that a lower frequency of the Ser482 allele and possibly a higher frequency of the GG genotype are associated with increased endurance performance ability.

The aim of the study was to investigate seasonal variations in fitness and performance indices of professional male soccer players. Eighteen professional male soccer players (age range 22–32 years) completed three similar sets of tests at three stages of the season: before preseason; after preseason and the middle of the competitive in-season. A significant decrease in body mass and percent fat was found during the preseason. A significant improvement (p < 0.05) was found in the vertical jump (preseason: 37.0 ± 5.3, post-preseason: 39.0 ± 4.8, mid-season: 40.3 ± 5.5 cm), the 4 × 10-m agility test (preseason: 8.1 ± 0.2, post-preseason: 7.9 ± 0.2, mid-season: 8.1 ± 0.3 s), flexibility (preseason: 45.2 ± 8.8, post-preseason: 48.2 ± 7.0, mid-season: 49.9 ± 6.9 cm) and aerobic capacity (preseason: 52.7 ± 6.6, post-preseason: 56.4 ± 6.0, mid-season: 57.4 ± 5.4 mL/kg/min) during preseason, with no further change during mid-season. Repeated sprint test (RST) (6 × 30-m) performance indices showed significant deterioration (p < 0.05) in ideal sprint time (IS; preseason: 21.8 ± 1.0, post-preseason: 23.0 ± 0.8, mid-season: 23.2 ± 0.8 s) and total sprint time (TS; preseason: 22.5 ± 0.7, post-preseason: 23.5 ± 0.6, mid-season: 23.8 ± 0.6 s) during preseason, with no further changes during mid-season. However, performance decrement (PD) significantly decreased during the preseason with no change during mid-season. The findings suggest that while power training was probably responsible for the anaerobic fitness improvement, the high-volume training led to improvement in aerobic fitness during the preseason. However, the low-intensity aerobic-type training, coupled with the high total training load, may have led to fatigue and decreases in IS and TS during the preseason.