The purpose of this study was to examine the effects of acute creatine-monohydrate supplementation on soccer-specific performance in young soccer players. Twenty young male soccer players (16.6 ± 1.9 years) participated in the study and were matched and allocated to 2 randomly assigned trials: ingesting creatine-monohydrate supplement (3 × 10-g doses) or placebo for 7 days. Before and after the supplementation protocol, each subject underwent a series of soccer-specific skill tests: dribble test, sprint-power test, endurance test, and vertical jump test. Specific dribble test times improved significantly in the creatine group (13.0 ± 1.5 vs. 10.2 ± 1.8 s; p < .05) after supplementation protocol. Sprint-power test times were significantly improved after creatine-monohydrate supplementation (2.7 ± 0.4 vs. 2.2 ± 0.5 s; p < .05) as well as vertical jump height (49.2 ± 5.9 vs. 55.1 ± 6.3 cm; p < .05) in creatine trial. Furthermore, dribble and power test times, along with vertical jump height, were superior in creatine versus placebo trial (p < .05) at post-supplementation performance. There were no changes in specific endurance test results within or between trials (p > .05). There were no between-trial differences in the placebo trial (p > .05). The main finding of the present study indicates that supplementation with creatine in young soccer players improved soccer-specific skill performance compared with ingestion of placebo.
Sergej M. Ostojic
Job Fransen, Thomas W.J. Lovell, Kyle J.M. Bennett, Dieter Deprez, Frederik J.A. Deconinck, Matthieu Lenoir, and Aaron J. Coutts
The aim of the current study was to examine the influence of restricted visual feedback using stroboscopic eyewear on the dribbling performance of youth soccer players. Three dribble test conditions were used in a within-subjects design to measure the effect of restricted visual feedback on soccer dribbling performance in 189 youth soccer players (age: 10–18 y) classified as fast, average or slow dribblers. The results showed that limiting visual feedback increased dribble test times across all abilities. Furthermore, the largest performance decrement between stroboscopic and full vision conditions was in fast dribblers, showing that fast dribblers were most affected by reduced visual information. This may be due to a greater dependency on visual feedback at increased speeds, which may limit the ability to maintain continuous control of the ball. These findings may have important implications for the development of soccer dribbling ability.
Keeron J. Stone and Jonathan L. Oliver
The aim of the study was to examine the effect of fatigue, developed during prolonged high-intensity intermittent exercise, on the performance of soccer shooting and dribbling skill.
Nine semiprofessional soccer players with a mean age of 20.7 ± 1.4 years volunteered to participate in the study. Participants completed a slalom dribble test and the Loughborough Soccer Shooting Test (LSST), before and directly following the performance of three 15-min bouts of a modified version of the Loughborough Intermittent Shuttle Test (LIST).
Mean heart rates and mean 15-m sprint times remained unchanged across the three bouts of the LIST. Following the LIST slalom dribbling time increased significantly by 4.5 ± 4.0% (P = .009), while the mean total points scored during the LSST was significantly reduced by 7.6 ± 7.0 points (P = .012). When fatigued the frequency of shots in the LSST achieving the highest score of 5 points was reduced by 47% while the frequency of shots achieving the lowest 0 point score increased by 85%.
Results show that while 45 min of exercise caused no decrements in sprint performance there were significant reductions in the ability to perform soccer-specific skills. Both the speed (dribbling time) and accuracy (shot performance) with which soccer-specific skills were executed was impaired following exercise replicating one-half of a soccer match.
Manuel D. Quinones and Peter W.R. Lemon
of blood glucose and blood lactate were collected during the passive recovery period after each exercise block (Figure 1 ). Ten minutes after completion of the final block, participants performed the RSA test, followed by two soccer skill tests: the slalom dribbling test (SDT) and the Loughborough
Javier Yanci, Daniel Castillo, Aitor Iturricastillo, Astrid Aracama, Alba Roldan, and Raúl Reina
&G_20–30 m), and the total time taken for the test (S&G_30 m) were recorded. Reina et al 4 showed good validity and reliability values for S&G with ball (ICC = .48, SEM = 9.8%) in CP footballers. Figure 1 Descriptions of (A) the Stop and Go test with the ball, (B) the Turning and Dribbling test with
Theofanis Tzatzakis, Konstantinos Papanikolaou, Dimitrios Draganidis, Panagiotis Tsimeas, Savvas Kritikos, Athanasios Poulios, Vasiliki C. Laschou, Chariklia K. Deli, Athanasios Chatzinikolaou, Alexios Batrakoulis, Georgios Basdekis, Magni Mohr, Peter Krustrup, Athanasios Z. Jamurtas, and Ioannis G. Fatouros
-Yo intermittent endurance level 2 test and the Yo-Yo intermittent recovery level 2 test as described elsewhere. 17 The creative speed and short dribbling tests were used to determine participants’ level of technical performance. 18 Performance Isometric strength, concentric and eccentric isokinetic peak torque
Konstantinos Papanikolaou, Panagiotis Tsimeas, Angeliki Anagnostou, Alexandros Varypatis, Christos Mourikis, Theofanis Tzatzakis, Dimitrios Draganidis, Dimitrios Batsilas, Theodoros Mersinias, Georgios Loules, Athanasios Poulios, Chariklia K. Deli, Alexios Batrakoulis, Athanasios Chatzinikolaou, Magni Mohr, Athanasios Z. Jamurtas, and Ioannis G. Fatouros
.81 (0.1) BMI, kg/m 2 24.0 (1.9) Body fat, % 20.7 (5.9) Body fat, kg 14.5 (5.4) Lean body mass, kg 58.8 (6.2) VO 2 max, mL/kg/min 56.8 (3.4) Yo-Yo IE2, m 2196.0 (246.1) Yo-Yo IR2, m 1272.0 (141.1) Creative speed test, s 16.7 (0.6) Short dribbling test, s 12.1 (0.5) Abbreviations: BMI, body mass index; VO
Iván Peña-González, Alba Roldan, Carlos Toledo, Tomás Urbán, and Raúl Reina
classification system. Hence, this study evaluated the content validity of the new classification system for CP football through a COD test (ie, modified agility test [MAT]) and explored the validity and reliability of a new dribbling test to correctly classify international CP football players. We hypothesized