Plyometric training (PT) is a widely used method to improve muscle ability to generate explosive power. This study aimed to determine whether preadolescent boys exhibit plyometric trainability or not. Forty-five children were randomly assigned to either a control (CG, N = 21, 10.6 ± 0.5 years; participated only in regular soccer practice) or a plyometric training group (PTG, N = 24, 10.6 ± 0.6 years; participated in regular soccer practice plus a plyometric exercise protocol). Both groups trained for 12 weeks during the in-season period. The PT exercises (forward hopping, lateral hopping, shuffles, skipping, ladder drills, skipping, box jumps, low-intensity depth jumps) were performed twice a week. Preadolescence was verified by measuring Tanner stages, bone age, and serum testosterone. Speed (0-10, 10-20, 20-30 m), leg muscle power (static jumping, countermovement jumping, depth jumping [DJ], standing long jump [SLJ], multiple 5-bound hopping [MB5]), leg strength (10 repetition maximum), anaerobic power (Wingate testing), and soccer-specific performance (agility, kicking distance) were measured at baseline, midtraining, and posttraining. The CG caused only a modest (1.2-1.8%) increase in speed posttraining. The PTG induced a marked (p < 0.05) improvement in all speed tests (1.9-3.1% at midtraining and 3-5% at posttraining) and vertical jump tests (10-18.5% at midtraining and 16-23% at posttraining), SLJ (2.6% at midtraining and 4.2% at posttraining), MB5 (14.6% at midtraining and 23% at posttraining), leg strength (15% at midtraining and 28% at posttraining), agility (5% at midtraining and 23% at posttraining), and kicking distance (13.6% at midtraining and 22.5% at posttraining). Anaerobic power remained unaffected in both groups. These data indicate that (a) prepubertal boys exhibit considerable plyometric trainability, and (b) when soccer practice is supplemented with a PT protocol, it leads to greater performance gains.

The purpose of the present study was to examine the effect of chronological age and gender on speed development during different sprinting phases in children and adolescents of both genders. The sample consisted of 360 sedentary pupils aged between 7 and 18 years, with 15 pupils representing each subgroup. The 30-m sprint speed was measured with photocells every 10 m. According to the results, boys and girls showed a gradual improvement in running speed during each sprint phase. The 18-year-old boys had significantly higher sprint speed in all measured distances compared to the 15-year-old or younger boys (p < 0.05), whereas the 18-year-old girls had significantly higher speed at the distances of 0 to 10, 10 to 20, 20 to 30, and 0 to 30 m compared to the 13- and 12-year-old or younger girls (p < 0.05). Significant differences between genders in the 15-years-old or older participants were observed. It is concluded that, from 7 to 18 years of age, gender and chronological age are factors that affect running speed during the 30-m sprint. Furthermore, the performance on each sprint phase is uniformly affected by the chronological age. Boys run faster than girls in all running phases, and the span between genders increases after the age of 15 years. It is useful that coaches take these findings into consideration when evaluating children in sprint performance.

Michaildis Y, Michaildis C, Primpa E. Analysis of goals scored in European Championship 2012. J. Hum. Sport Exerc. Vol. 8, No. 2, pp. 367-375, 2013. The purpose of the present study was to evaluate goal scoring characteristics of European Championship 2012 and the sample consisted of all the games of the final phase of the organization (N=31). The statistical analysis of the results was conducted with the use of the non parametric chi square test. According to the results of the present study the short pass (<10m) was the basic final attacking action in most of the goals (18.4%) when the long pass was at the second place (>10m) (17.1%) and the individual action at third place (14.5%). Most of the goals (40.8%) were scored with shot and then with header (27.6%) and with the inner part of the foot (21.1%). Also the most of the goals achieved through the penalty box (71.1%) (p<0.001). Finally when a team scored the first goal was the winner of the match (70.97%). The findings indicate to the coaches to use a lot of offensive exercises with short and long passes. Also the most of exercises have to locate inside the penalty box. As concerns the impact of the first goal was strong for the match outcome, so the teams have to be prepared to deal with a situation that the opponent scored the first goal.

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