The purpose of the present study was to compare maximal isometric force, force-time curve characteristics, pedaling rate, vertical jump, and sprint performance among young soccer players from different competition levels. Fifty-four (54) young soccer players were divided into three groups according to competition level: the elite group (n = 18) consisted of soccer players from the national youth soccer team of Greece, the subelite group (n = 18) consisted of youth soccer players who participated in the local championship, and the recreational group (n = 18) consisted of recreational soccer players. All groups were evaluated for maximal isometric force, explosive force at 100 msec, peak force relative to body mass, rate of force development, squat and drop jump heights, 10 m sprint time, and pedaling rate. The elite group presented significantly (p < 0.05) higher maximal isometric force, vertical jump height, and pedaling rate, and lower 10 m sprint time in comparison with the subelite and recreational groups. No significant differences were observed in strength and speed characteristics between the subelite and recreational young soccer players. The findings of the present study suggest that the elite young soccer players can be distinguished from subelite and recreational young soccer players in strength and speed characteristics. These strength and speed measures can be used for strength and speed diagnosis, and for designing and evaluating training programs.

The aim of the present trial was to investigate the effect of two stretching programs, a dynamic and a static one, on the sprint ability of recreational volleyball players. The sample consisted of 27 male recreational volleyball players (age 21.6 ± 2.1 years, mean ± standard deviation, body mass 80.3 ± 8.9 kg, height 1.82 ± 0.06 m, body mass index 24.3 ± 2.5 kg.m⁻², volleyball experience 7.7 ± 2.9 years). Participants were randomly divided into three groups: (a) the first performing dynamic stretching exercises three times per week, (b) the second following a static stretching protocol on the same frequency, and (c) the third being the control group, abstaining from any stretching protocol. The duration of the stretching exercise intervention period was 6 weeks, with all groups performing baseline and final field sprinting tests at 4.5 and 9 m. The post-test sprint times were faster in both the 4.5 (p = 0.027, η² = 0.188) and 9 m tests (p < 0.001, η² = 0.605) compared to the pre-test values. A large time × group interaction was shown in both the 4.5 (p = 0.007, η² = 0.341) and 9 m tests (p = 0.004, η² = 0.363) with the static and dynamic stretching groups being faster in the post-test than in the pre-test, whereas no change was found in the control group. The percentage change in the 4.5 m sprint time correlated with volleyball experience (r = −0.38, p = 0.050), i.e., the longer the volleyball experience, the larger the improvement in the 4.5 m sprint. Thus, it is concluded that both stretching techniques have a positive effect on the velocity of recreational male volleyball players, when performed at a frequency of three times per week for 6 weeks under the same conditions as defined in the study protocol.

The aim of this study was to apply a training plan to four different-length microcycles (MIC) in soccer and analyze (a) the load within the training weeks and (b) the short-term effect on the matches that were played at the end of each microcycle. An intervention training program applied to microcycles of five, six, seven and nine days during two seasons of the Cypriot Fist Division. The GPS technology and subjective (wellness, RPE) assessments were used to monitor the load throughout trainings and games. In weekly external load, there were differences between the four microcycles, with a lower load in MIC5 for all the parameters and higher on MIC9 in the most of them (p < 0.05). In RPE, MIC9 (229 ± 60 arbitrary units (au)) differed significantly from MIC5 (229 ± 60 au, p < 0.001), MIC6 (281 ± 67 au; p < 0.001) and MIC7 (297 ± 48 au, p = 0.009). MIC5 also differed from MIC6 (p = 0.001) and MIC7 (p < 0.001). In the game external load, the only differences found in GDEC2 (game decelerations) were between MIC7 (68 ± 10 number (n)), MIC5 (61 ± 11 n, p = 0.035) and MIC6 (60 ± 10 n, p = 0.002); in GSPEF (game speed efforts), between MIC5 (40 ± 17 n), MIC7 (48 ± 14 n, p = 0.004) and MIC9 (48 ± 16 n, p < 0.001) and between MIC6 (41 ± 14 n), MIC7 (p = 0.009), and MIC9 (p = 0.009); in GMPW5 (game metabolic power efforts), between MIC7 (1307 ± 271 n), MIC5 (1201 ± 340 n, p = 0.035) and MIC6 (1178 ± 261 n, p = 0.001). No differences were found for wellness and perceived exertion. It is important for performance coaches to adapt the training load to the length of the microcycle, applying a lower load to short training weeks and manage the load fluctuation on long training weeks in terms of volume, intensity and recovery. In our study, the results confirmed that this strategy could result in similar performance in the games, regardless of microcycle length.

The aim of the present study was to evaluate the levels of homocysteine and 8-iso PGF_2a in football and hockey players before and soon after a match, on the predisposition for development of atherosclerosis. We measured 8-iso-PGF_2a and homocysteine in 21 football athletes aged 21.8 ± 3.7 years old and 18 hockey athletes 22.2 ± 3.3 years old, respectively. All the athletes presented significant increases in serum homocysteine levels following the match (p = 0.001 for football and p = 0.001 for hockey players) Also a statistically significant increase of 8-iso-PGF_2a levels was found in hockey and football athletes following the match (p < 0.001 and p = 0.071). Our findings suggest that strenuous exercise such as a football or a hockey match causes a marked increase in serum homocysteine and 8-iso-PGF_2a. Due to the fact that homocysteine and 8-iso-PGF_2a are contributing to atheromatosis, it may be useful to follow a restoration exercise program that involves mild exercise and to pay special attention to folate, vitamin B6, and vitamin B12 balance during the first 24 h after the match.

The purpose of this study was to (a) correlate the weekly external training load with the game running performance in season microcycles and (b) specify the optimal training/game ratio of the weekly external load in elite youth soccer players. The total distance (TD), the high-speed running distance (HSRD) (19.8–25.2 km/h), the ZONE6 distance (>25.2 km/h), the acceleration (ACC) (≥+2 m/s²), and the deceleration (DEC) (≥−2 m/s²) were monitored with global positioning system (GPS) technology throughout 18 microcycles and official games. TD had a very high positive correlation average (r = 0.820, p = 0.001), the HSRD had a high positive correlation average (r = 0.658, p = 0.001), the ZONE6 distance and DEC had a moderate positive correlation average ((r = 0.473, p = 0.001) and (r = 0.478, p = 0.001), respectively), and the ACC had a low positive correlation average (r = 0.364, p = 0.001) between microcycles and games. Regarding the training/game ratio, the HSRD showed statistically significant differences between ratios 1.43 and 2.60 (p = 0.012, p ≤ 0.05), the ACC between ratios 2.42 and 4.45 (p = 0.050, p ≤ 0.05) and ratios 3.29 and 4.45 (p = 0.046, p ≤ 0.05), and the DEC between ratios 2.28 and 3.94 (p = 0.034, p ≤ 0.05). Considering the correlation between weekly training and game external load, high weekly training TD values correspond to higher game values, whereas HSRD, ZONE6 distance, ACC, and DEC, which determine training intensity, should be trained in a specific volume. Training/game ratios of 1.43, 2.42 to 3.29, and 2.28 to 3.11 seem to be optimal for HSRD, ACC, and DEC weekly training, respectively.

The purpose of this study was to assess the kinematic characteristics of the gait of preschoolers before and after the implementation of an intervention training program. A group of twenty preschoolers without motor disorders participating in the study were assigned to two groups: the experimental group-10 preschoolers (mean age 4.9±0.2 years)-and the control group-10 preschoolers (mean age 4.8±0.3 years). Participants were assessed using the same test before and after the implementation of the intervention training program: they had to walk in a straight line three times along a distance of 5 meters (m). Kinematic variables were analysed based on 3D video processing using APAS software. Repeated Measures ANOVA was used to examine the effectiveness of the intervention training program (p<0.05). Results indicated that there were statistically significant differences in the Displacement of the Center of Mass during the Right Foot Support phase. There is a need for intervention training programs to enhance motor skill levels and the quality of movement in all children.