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This investigation explored relationships between biological maturation, physical and academic performance in young male soccer players. Thirty-eight players (age: 9.79 ± 1.21 years; body mass index (BMI): 20.4 ± 2.39 kg/m2; body fat: 16.8 ± 2.21%) participated. Measures of anthropometry used for body mass, body fat percentage (%BF), and BMI as well. Postural control, 15 m sprint, squat jumps and counter-movement jumps (SJ, CMJ), and T-half test for change-of-direction (CoD) were parameters of physical performance. The grade point average (GPA) of mathematics determined academic attainment. Moore’s equations were used to estimate their maturity status (PHV). Biological maturation was highly correlated with most (not 15 m sprint) physical and academic performance parameters, especially CMJ (r = -0.812) and mathematics (r = -0.781). Academic performance showed the largest relations to the jumping performance (CMJ: r = 0.771; SJ: r = 0.723). In contrast, anthropometric and fatness parameters were not relevantly (r ≥ 0.5) correlated with any other parameters. The largest correlations were calculated for sitting height vs. SJ (r = -0.408), sitting height vs. postural control (r = -0.355), leg length vs. postural control (r = -0.339). As a result, it is essential to take biological maturation inconsideration while assessing the physical and academic achievement of young soccer players. In consequence, soccer coaches and physical education (PE) teachers should be cognizant of the impact of biological maturity on physical and academic performance to assist fair and equal opportunities for achievement in young players.

Introduction: This study aimed to compare 10–12-year-old Qatari male soccer players (n = 45) regarding different dimensions (anthropometric, academic and physical performance). Methods: Anthropometric parameters (body mass, fat percentage (%BF), body mass index (BMI)) academic achievement (mathematics and science grade point average [GPA]) and physical performance [Yo-Yo Intermittent Recovery Test (level 1), squat jumps (SJ), counter-movement jumps (CMJ), stork balance test, 10 and 15 m sprint tests, T-half test for change-of-direction (CoD) ability, hand-grip strength, medicine ball throw (MBT)] were measured. Schoolchild soccer players were divided into three groups: 12-year-old players (U12; n = 16), 11-year-old players (U11; n = 14), 10-year-old players (U10; n = 15). Results: Apart from mathematics, Yo-Yo IR1 and 10 m sprint, all performance parameters showed significant age effects. The largest age-related difference was observed for 15 m sprint (p < 0.001). Both adjacent age groups displayed significant differences for 15 sprint (U10 vs. U11: p = 0.015; U11 vs. U12: p = 0.023). Concerning academic performance, a significant age effect was found for science (p < 0.001). There was a main age effect on academic performance difference between U10 and U11 (p = 0.007). Academic parameters did not correlate with any physical performance parameter or anthropometric parameter. The strongest correlations were detected for body height and agility T-half test (r = −0.686) and medicine ball throw (r = 0.637). The biological maturity was strongly correlated with handgrip strength (r = −0.635). Discussion: Soccer coaches and physical education teachers can use these data as reference values for evaluation of school-aged soccer players, and for ascertaining specific training targets. Obviously, short sprinting ability and aerobic capacity are not functions of age and need a specific training for significant improvements.

The in ovo sexing of chicken eggs is a current task and a prerequisite to overcome the mass killing of male day-old chicks from laying lines. Although various methods have been developed and tested in recent years, practicable methods for sex determination are still missing which can be applicated in poultry hatcheries before the chicken embryo is capable of nociception and pain sensation. Optical spectroscopic methods enable an early determination of the sex. In this study, a novel method based on two-wavelength in ovo fluorescence excitation is described. More than 1600 eggs were examined. In ovo fluorescence was sequentially excited at 532 nm and 785 nm. The fluorescence intensities of the spectral regions behave inversely with respect to sex. It is shown that the observed sex-related differences in the fluorescence intensities are based on the embryonic hemoglobin synthesis. The accuracy of sex determination is 96% for both sexes. The hatching rate is not reduced compared to an equivalent reference group.