Aristomenis Sotiropoulos

Strength and Speed Characteristics of Elite, Subelite, and Recreational Young Soccer Players

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.

Effects of Two Different Half-Squat Training Programs on Fatigue During Repeated Cycling Sprints in Soccer Players

Bogdanis, GC, Papaspyrou, A, Souglis, AG, Theos, A, Sotiropoulos, A, and Maridaki, M. Effects of two different half-squat training programs on fatigue during repeated cycling sprints in soccer players. J Strength Cond Res 25(7): 1849-1856, 2011—This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal half-squat strength increased significantly in both groups (p < 0.01), but this increase was significantly greater in the S-group compared with the H-group (17.3 ± 1.9 vs. 11.0 ± 1.9%, p < 0.05). Lean leg volume (LLV) increased only in the H-group. Total work over the 10 sprints improved in both groups after training, but this increase was significantly greater in the second half (8.9 ± 2.6%) compared with the first half of the sprint test (3.2 ± 1.7%) only in the S-group. Mean power output (MPO) expressed per liter of LLV was better maintained during the last 6 sprints posttraining only in the S-group, whereas there was no change in MPO per LLV in the H-group over the 10 sprints. These results suggest that resistance training with high loads is superior to a moderate-load program, because it increases strength without a change in muscle mass and also results in a greater improvement in repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players.

The effect of high vs. low carbohydrate diets on distances covered in soccer.

Abstract Souglis, AG, Chryssanthopoulos, CI, Travlos, AK, Zorzou, AE, Gissis, IT, Papadopoulos, CN, and Sotiropoulos, AA. The effect of high vs. low carbohydrate diets on distances covered in soccer. J Strength Cond Res 27(8): 2235–2247, 2013—The purpose of this study was to compare the distances covered during a 11-a-side soccer match after players had consumed either a high carbohydrate (CHO) or a low CHO diet. Twenty-two male professional soccer players formed 2 teams (A and B), of similar age, body characteristics, and training experience. The 2 teams played against each other twice with a week interval between. For 3.5 days before the first match, the players of team A followed a high CHO diet that provided 8 g CHO per kg body mass (BM) (HC), whereas team B players followed a low CHO diet that provided 3 g CHO per kg BM (LC) for the same time period. Before the second match the dietary treatment was reversed and followed for the same time period. Training during the study was controlled, and distances covered were measured using global positioning system technology. Every player covered a greater total distance in HC compared with the distance covered in LC (HC: 9,380 ± 98 m vs. LC: 8,077 ± 109 m; p < 0.01). All distances covered from easy jogging (7.15 km·h−1) to sprinting (24.15 km·h−1) were also higher in HC compared with LC (p < 0.01). When players followed the HC treatment, they won the match (team A vs. team B: 3-1 for the first game and 1-2 for the second game). The HC diet probably helped players to cover a greater distance compared with LC. Soccer players should avoid eating a low (3 g CHO per kg BM) CHO diet 3–4 days before an important soccer match and have a high CHO intake that provides at least 8 g CHO per kg BM.

The effect of a 4-week training regimen on body fat and aerobic capacity of professional soccer players during the transition period.

Sotiropoulos, A, Travlos, AK, Gissis, I, Souglis, AG, and Grezios, A. The effect of a 4-week training regimen on body fat and aerobic capacity of professional soccer players during the transition period. J Strength Cond Res 23(6): 1697-1703, 2009-The purpose of this study was to evaluate the changes in body fat percentage and aerobic capacity in professional soccer players, after the implementation of a specific 4-week training regimen during the transition period. Fifty-eight professional soccer players of the Greek Premier National Division were separated in experimental (n = 38) and control groups (n = 20). Body composition and maximum oxygen intake were evaluated before and after a 4-week training regimen followed during the transition period. The experimental design used for analyzing weight (kg), percent body fat (%) and &OV0312;O2 max values (ml·kg−1·min−1) was a 2 × 2 (Groups × Measures), with Groups as a between-subjects factor and Measures as a within-subjects factor. The level of significance was set at p ≤ 0.05 for all analyses. Analyses of variances showed that the experimental and the control groups achieved statistically significant (a) increases from pretest to posttest measures in body weight (0.595 kg and 1.425 kg, respectively) and percent body fat (0.25 and 0.82, respectively), and (b) decreases in &OV0312;O2max values from pretest to posttest measures (0.81 and 3.56, respectively). The findings of the study revealed that the players who followed the training regimen compared with the players that did not follow any specific training program gained less weight and body fat and exhibited lower reduction in their &OV0312;O2 max values.

Multiarticular Isokinetic High-Load Eccentric Training Induces Large Increases in Eccentric and Concentric Strength and Jumping Performance

Abstract Papadopoulos, C, Theodosiou, K, Bogdanis, GC, Gkantiraga, E, Gissis, I, Sambanis, M, Souglis, A, and Sotiropoulos, A. Multiarticular isokinetic high-load eccentric training induces large increases in eccentric and concentric strength and jumping performance. J Strength Cond Res 28(9): 2680–2688, 2014—This study investigated the effects of short-term eccentric exercise training using a custom-made isokinetic leg press device, on concentric and eccentric strength and explosiveness as well as jumping performance. Nineteen healthy males were divided into an eccentric (ECC, n = 10) and a control group (CG, n = 9). The ECC group trained twice per week for 8 weeks using an isokinetic hydraulic leg press machine against progressively increasing resistance ranging from 70 to 90% of maximal eccentric force. Jumping performance and maximal force generating capacity were measured before and after eccentric training. In the ECC group, drop jump (DJ) height and maximal power were increased by 13.6 ± 3.2% (p < 0.01) and 25.8 ± 1.2% (p < 0.01), whereas ground contact time was decreased by 17.6 ± 2.6% (p < 0.01). Changes in ankle, knee, and hip joint angles were also reduced by 33.9 ± 1.1%, 31.1 ± 1.0%, and 32.4 ± 1.6% (all p < 0.01), respectively, indicating an increase in muscle stiffness during the DJ. Maximal eccentric and concentric leg press force was increased by 64.9 ± 5.5% (p < 0.01) and 32.2 ± 8.8% (p < 0.01), respectively, and explosiveness, measured as force attained in the first 300 milliseconds, was increased by 49.1 ± 4.8% (p < 0.01) and 77.1 ± 7.7% (p < 0.01), respectively. The CG did not show any statistically significant changes in all parameters measured. The main findings of this study were that maximal concentric and eccentric force, explosiveness, and DJ performance were markedly increased after only 16 training sessions, possibly because of the high eccentric load attained during the bilateral eccentric leg press exercise performed on this custom-made device.

Muscle-contraction properties in overarm throwing movements.

On the basis of dynamic and kinematic data, this study identifies the type of muscle contraction in unloaded over-arm throwing movements. An unloaded throw or nearly unloaded throw is defined as the throw in which the external resistance is too small (e.g., the team handball, baseball, and water polo throws as well as the tennis and badminton smashes). A special arm-force–measuring apparatus was constructed to imitate an overarm throw. Forty-two subjects were placed into 3 groups: untrained subjects, weight-trained athletes, and team handball players. The measured parameters included the velocity of the initial movement, the release velocity, the velocity of the first 50 milliseconds of the concentric phase, the force value at the moment of deceleration of the initial movement, and the impulse values during the eccentric and concentric phases of the test movement. Statistically significant higher values of the above parameters (p < 0.05) were determined in that test at which the initial speed of movement was higher. Also, the correlation coefficients of the parameters of the initial phase of the throw movement were very high (p < 0.001), especially the parameters related with the movements first 50 milliseconds. The results support the thesis that the stretch–shortening cycle is the type of muscle contraction in unloaded overarm throws. Furthermore, it is possible to increase the throw velocity by increasing the velocity of the initial movement (i.e., by provoking higher inertia forces).

Changes in Homocysteine and 8-iso-PGF2a Levels in Football and Hockey Players After a Match

The aim of the present study was to evaluate the levels of homocysteine and 8-iso PGF2a in football and hockey players before and soon after a match, on the predisposition for development of atherosclerosis. We measured 8-iso-PGF2a 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-PGF2a 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-PGF2a. Due to the fact that homocysteine and 8-iso-PGF2a 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.