To determine the cardiac response to intensive endurance training during prepuberty, we studied 22 male prebubertal swimmers who had been trained for at least 3 years, with a mean of 3.91 years and a standard deviation of 1.10 years, and 8 hours per week, the mean being 10.0 hours and the standard deviation 1.7 hours. The control group consisted of 21 boys of similar age, height and weight (p is more than 0.05 for all), who were not participating regularly in sporting activities. Left ventricular dimensions and systolic function were examined with M-Mode; velocities and durations of transmitral flow were measured with pulsed wave Doppler; and tissue Doppler velocities and durations were measured with pulsed wave tissue Doppler echocardiography. We determined the regional velocities of the lateral mitral annulus in four-chamber position, the left ventricular posterolateral wall, and the midseptum in long-axis position. Interventricular septal thickness, left ventricular posterior wall thickness, left ventricular mass and relative wall thickness were increased in swimmers (p is less than 0.05). All the tissue Doppler measurements were similar in both groups, except the septal isovolumic relaxation time. We observed that the left ventricular wall thickness had increased concentrically in prepubertal swimmers compared to controls, without a significant change in the left ventricular diastolic diameter. This finding is contrary to the previous studies on adult swimmers. Whether the structural changes observed in our study reflect the unique cardiac adaptation of the hearts of children to exercise will only be disclosed by longitudinal studies of prepubertal athletes.

The aim of this study was to examine the effect of differential learning activities on young football players’ skills. Athletes who had played active football for at least 2 years in the youth teams participating in competitions in Amateur Leagues in Istanbul, Turkey took part in the study, as the Experimental Group (EG; n=26, age=12.03±0.44) and Control Group (CG, n=26, age=12.05±0.46). In the study, differential learning exercises integrated into their training programme for a period of 8 weeks, 3 days per week, were applied to the players in the EG immediately following warm-up, while the players in the CG continued with their traditional training programmes. The Illinois Test with Ball (ILL), Creative Speed Test (CST), Ball-Dribbling Test (DT), Ball-Juggling Test (JT) and Passing Test (PT) were carried out with all players participating in the study as a pretest prior to commencement of the programme and as a posttest following the implementation of the programme, and the gathered data were analyzed statistically. The findings obtained revealed that in the within-group pretest and posttest, players in the EG showed a statistically significant improvement in all parameters (p<0.05), while players in the CG showed a statistically significant improvement in ILL, CST, JT and PT (p<0.05). When the differences in development of the groups were compared, a statistically significant difference in the ILL, CST and DT parameters was determined in favor of the players in the EG (p<0.05). Consequently, although regularly-performed classic football training develops skills, it is seen that differential learning exercises integrated into training programmes are more effective for dribbling skills. It is considered that differential learning exercises, in which the non-dominant leg is frequently used, can make it easier for players to apply the necessary skills by allowing them to give more effective responses to the tricky positions encountered in football, and that these exercises can support the development of players’ performances.

In this study, it was aimed to determine the effects of plyometric exercises applied on unstable platforms on static and dynamic balances of soccer players who continued their high school education. In the study, male soccer players with similar socio-economic status between the ages of 14 and 16 formed the study group (SG; n=24; age=15.08±1.36) and the control group (CG; n=22; age=15.22±1.62). Static Balance Eyes Open (SB-EO), Static Balance Eyes Closed (SB-EC) and Dynamic Balance tests (DB) were applied on the SG and CG as pre- and post-tests for both dominant leg (DL) and non-dominant leg (NDL). SG athletes were subjected to plyometric exercises on unstable surfaces for sixteen sessions that were integrated into the physical education lessons in high school while CG athletes performed only a traditional soccer training program. As a result of the statistical analyses, when the pre-post test scores of the SG were examined, dynamic balance-dominant leg (DB-DL; p=0.03), dynamic balance-non-dominant leg (DB-NDL; p=0.03), static balance eyes open-dominant leg (SB-EO-DL; p=0 01), static balance eyes closed -dominant leg (SB-EC-DL; p=0.03) and static balance eyes closed-non-dominant leg (SB-EC-NDL; p=0.01) measurements were found statistically significant (p<0.05) while the CG had statistical improvements only in SB-EO-DL measurements (p=0.03). When the differences between the two groups were examined, only SB-EC-DL measurements were found statistically significant in favor of the SG (p=0.03). In conclusion, especially the improvement of DL observed in the SG is important for optimum performance considering that it is necessary to use both legs effectively in soccer. Considering the multitude of activities performed on a single leg in soccer, it is thought that the increase in bilateral balance can improve the skills that determine soccer performance in difficult conditions such as dribbling, shooting and passing.