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Original Research

Acute Effects of Different Warm-Up Methods on Sprint, Slalom Dribbling, and Penalty Kick Performance in Soccer Players

Gelen, Ertugrul

Author Information
Journal of Strength and Conditioning Research: April 2010 - Volume 24 - Issue 4 - p 950-956
doi: 10.1519/JSC.0b013e3181cb703f
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Abstract

Introduction

Soccer is a sport that is based on explosive actions such as kicking, dribbling, jumping, and sprinting (26). Players do warm-up exercises before sportive loading to improve motor performance and avoid injuries. The main goal of warm-up is to increase muscle heat, blood circulation, and physiological response (17). Static stretching is usually done during the warm-up period. For warm-up, players traditionally do static stretching exercises after a few minutes of moderate aerobic exercise (jogging). It is determined that static stretching increases muscle-skeleton flexibility by affecting both mechanical (21) and neurological (15) characteristics of the muscle-tendon unit (MTU). But the belief about the significance of static stretching exercise before the event has started to be interrogated in recent years (3,6,8,23,29).

Recent studies show that static stretching exercises can inhibit the performance by decreasing the production of power and speed instead of being useful to athletes (3,6,7,18,23,30). The most-accepted explanation about the decrease in performance is that static stretching exercises soften the MTU and decrease muscle stiffness. The decrease in MTU stiffness causes acute neural inhibition and decreases the production of power and speed by leading to a reduction in stimulus that goes to the muscles (2,19,21,27).

Recently, compared with static stretching, practicing warm-up exercises has attracted the attention of many researchers, trainers, and sports experts (7,9,12,31). Hops, skips, and jumps, which aim at upper and lower extremities, constitute the heart of dynamic warm-up exercises. Dynamic warm-up exercises include plyometrics, heavy-load resistance exercise, or maximum voluntary contractions (MVC). Previous research studies suggested that voluntary moderate- to high-intensity contractions, such as warm-ups, which are performed before practicing an athletic activity, increase power production and performance by activating neuromuscular functions (5,9,14,23,31). This phenomenon is called “postactivation potentiation” (PAP). Postactivation potentiation is defined as the temporary increase in the contractile ability of muscles after previous contraction sessions (28). Although a more effective interaction between actin and myosin resulting from phosphorylation of light chain myosin is considered as one of the main mechanisms responsible for PAP, another mechanism is neural excitability (13,28).

Although there are studies documenting the detrimental effects of static stretching and useful effects of dynamic exercises, up to the present, no studies have researched on the acute effects of different warm-up exercises on sprint, slalom dribbling, and penalty kick performances in soccer. Notwithstanding that sprint, slalom dribbling, and penalty kick are very important for soccer and are often applied in competition and training. The first hypothesis of this study is about performances of sprint, slalom dribbling, and penalty kick to be reduced by static stretching, besides performance to be increased by dynamic exercises. Another important matter is the requirement of sportsmen to apply static stretching before training or competition for not to be spoiled. The main objective in static stretching before activity is to reduce risk of spoiling by increasing the range of motion of muscles. But there is an accurate balance between the reduction of performance in applying static stretching and the increasing of spoiling risk in nonapplication of it. The second hypothesis of this study is about application of static stretching and dynamic exercise combination that can reduce the detrimental effects of static stretching on sprint, slalom dribbling, and penalty kick performances. Therefore, the purpose of this study was to compare the acute effects of static stretching, dynamic exercise, and combined static stretching and dynamic exercise on sprint, slalom dribbling, and penalty kick performance in professional soccer players.

Methods

Experimental Approach to the Problem

A within-subject, balanced, randomized repeated-measures design was used to test the experimental hypotheses. Twenty-six professional soccer players were familiarized with all experimental tests before baseline performance was determined. The study consisted of 4 experimental sessions. At each session, subjects performed 1 of 4 different warm-up methods (i.e., neither stretching nor dynamic exercise [control], static stretching, dynamic exercise warm-up, and combined static stretching and dynamic exercise warm-up) after a standardized 5-minute jogging warm-up and then completed the soccer performance tests. The performance tests consisted of sprint, slalom dribbling, and penalty kick. Three trials were performed for each test. For each variable, the highest value of the 3 attempts was used for analysis.

Subjects

The study has been conducted on 26 healthy male volunteer professional soccer players who play in the third soccer league of Turkey (mean [SD]: 23.3 [3.2] years, 178.2 [6.1] cm, and 73.0 [6.5] kg). Players have a training experience of 9.6 (2.1) years. All subjects indicated had no significant history of recent musculoskeletal injury. Before participating in the study, subjects were informed of the potential risks and benefits and provided written informed consent to participate in accordance with the policies and procedures of the University of Sakarya's Human Research Ethics Committee for use of human subjects in research. Tests were performed in the fourth week of a 16-week season. During the season, the subjects practiced 16 times per week and played 1 professional match, with no additional weight training being undertaken. During resting, ranges of motion of all soccer players were measured using a goniometer, and it was determined that they were within normal limits. The subjects were asked to refrain from caffeine intake on each testing day and to avoid food consumption in the 2 hours before testing.

Procedures

Before data collection, all subjects participated in 2 introductory sessions during which they practiced all warm-up procedures and soccer fitness tests. This introductory period was designed to reduce the influence of any learning effects caused solely by the mechanics of performing study protocols. All warm-up exercises were carried out by a team trainer in 10-person groups, at the same hours (11.00 am). Each of 4 warm-up methods was carried out on nonconsecutive and random days. It was started with 5 minutes of jogging with low intensity warm-up methods. All Subjects relaxed actively for 2 minutes before applying any warm-up methods after 5 minutes of jogging (by walking). After this relaxed walking, warm-up methods were applied. Subjects had relaxed for 4-5 minutes after completion until application of the first test. All subjects rested at least 3 minutes between tests and completed the soccer test battery in about 15-20 minutes. All study procedures were completed within 11 days. A summary of experimental and testing procedures is shown in Figure 1. For ease of discussion, the 4 warm-up methods will be referred to as Method A, Method B, Method C, and Method D.

Figure 1
Figure 1:
A summary of the experimental method.

Method A consisted of low-intensity aerobic jogging for 5 minutes. Subjects were made to run around the soccer ground for 5 minutes with such an intensity that their heart rate was 140 times per minute. In each group of 10 people, 3 subjects selected randomly were made to wear a heart rate monitor (810i Polar Electro Inc., Kempele, Finland) to measure warm-up intensity. After 5 minutes of jogging, not applying any stretching or dynamic exercises, 4-5 minutes later, sprint, slalom dribbling, and penalty kick tests had been applied. Method A is a warm-up application used in all sports.

Method B consisted of low-intensity aerobic jogging (Method A) and static stretching intended for lower extremity muscles for 10 minutes (active stretching). Subjects performed 5 stretches in a slow, deliberate manner with proper body alignment. Subjects held each stretch for 20 seconds at a point of mild discomfort, relaxed for 10 seconds, then repeated the same stretch for another 30 seconds before progressing to the opposite extremity (when necessary). The static stretching exercises intended for specific muscle groups were performed in accordance with the method suggested by Alter (1) (calf #21, quadriceps #91, adductor #64, hamstring #46, and hip rotator #118) (Table 1). The team trainer monitored the subjects during each stretch to ensure that the stretch was performed correctly. Four to five minutes later, Method B was applied to sprint, slalom dribbling, and penalty kick tests.

Table 1
Table 1:
Static stretching exercises.

Method C consisted of low-intensity aerobic jogging (Method A) and 12 dynamic warm-up exercises for 10 minutes (Table 2). Subjects performed each dynamic exercise for 15 m, rested about 10 seconds, and then repeated the same exercise for 15 m as they returned to the starting point. Subjects were continually instructed to maintain proper form and technique during the performance of each dynamic movement. This method was designed similar to warm-up protocols typically used to prepare athletes for sports participation (7,8). Four to five minutes later, Method C was applied to sprint, slalom dribbling, and penalty kick tests.

Table 2
Table 2:
Dynamic warm-up exercises.

Method D consisted of a combination of Method B and Method C. After low-intensity aerobic jogging for 5 minutes, subjects performed static stretching designed for lower extremity muscles (Method B) first and then dynamic warm-up exercises (Method C). Four to five minutes later, Method D was applied to sprint, slalom dribbling, and penalty kick tests.

Soccer-Specific Tests

The subjects performed 3 skill tests, a sprint test, a slalom dribble test, and penalty kick test. For the sprint test, subjects ran between 2 lines, the distance of which was 30 m, by using their maximum strength with upright start at any time they wished. For the slalom dribbling test, they performed dribbling by zigzagging between 4 cones, which were installed at intervals of 2 m along a straight line of 10 m. Electronic timing lights (NewTest 2000, Oulu, Finland) were used to measure the time taken for the 30-m sprint and slalom dribbling test. Sprint and slalom dribbling tests were performed by the subjects 3 times, and the best values were used for analysis. Penalty kick test was performed from the penalty point having a distance of 11 m from the goal line with maximal speed. For standardization of shoots, the subjects performing the penalty shoot kick had been asked to shoot by targeting exactly the plastic man placed in the middle of the goal between the goal line and goal net without requiring a hit. The radar gun used for measuring the speed of the ball (SportsRadar 3600, Astro Products, Ontario, CA, USA) had been installed on a tripod with an angle of 10° 5 m behind the player performing the penalty kick and on the side of his dominant leg. To make the maximal effort, the feedback of the speed had been given to the subjects. For data analysis, the fastest (km?h−1) of the 3 penalty kicks performed by the player at the maximal speed had been analyzed and determined as maximal penalty kick speed (Vmax). All testing sessions were performed with identical equipment, positioning, technique, and test order.

Statistical Analyses

Descriptive statistics (mean ± SD) were formulated for the variables age, height, body weight, sprint, slalom dribbling, and penalty kick. Data obtained for each of the 4 warm-up methods are analyzed using repeated-measures analyses of variance. Methods B-D were used for the study group, whereas Method A was designed for the control group. When a significant F value was achieved, post hoc comparisons were accomplished via a least significant difference test to identify specific differences between trials. An intraclass correlation (ICC Rs) was calculated for each test measure after each of the 4 warm-up methods to examine the reliability of each test.

Results

The mean scores for the sprint, slalom dribbling, and penalty kick performance measures after using the different warm-up methods are presented in Table 3. In terms of sprint performances, a 0.39-second difference (% 8.5) between Method A and Method B, a 0.19-second difference (% 4.1) between Method A and Method C were found to be significant in terms of statistics (p < 0.01 and p < 0.03, respectively). In terms of slalom dribbling performances, a 0.24-second difference (% 4.1) between Method A and Method B, a 0.30-second difference (% 5.1) between Method A and Method C were found to be significant in terms of statistics (p < 0.02 and p < 0.01, respectively). In terms of penalty kick performances, a 2.09 km·h−1 difference (% 2.1) between Method A and Method B, a 3.31 km·h−1 difference (% 3.3) between Method A and Method C were found to be significant in terms of statistics (p < 0.01 and p < 0.03, respectively). It has also been found that combined static stretching and dynamic exercises have no effect on sprint, slalom dribbling, and penalty kick (p > 0.05). Reliability ICC Rs for the dependent variables were 0.87-0.91. In conclusion, static stretching exercises performed after low-intensity aerobics type jogging affect sprint, slalom dribbling, and penalty kick performances negatively. Besides, dynamic warm-up exercise applications affect sprint, slalom dribbling, and penalty kick performances positively.

Table 3
Table 3:
Sprint, slalom dribbling, and penalty kick performance after different warm-up methods (n = 26).

Discussion

The purpose of this study was to compare the acute effects of static stretching, dynamic exercise, and combined static stretching and dynamic exercise on sprint, slalom dribbling, and penalty kick performance in professional soccer players. The most striking result of this study is that despite there being a marked decrease in sprint, slalom dribbling, and penalty kick performance when static stretching is combined with warm-up, there occurs an increase in the aforementioned performances when dynamic exercises are used. Results of this study support the hypothesis that static stretching reduces sprint, slalom dribbling, and penalty kick performances, besides dynamic warm-up exercises increasing the performance. Besides, combined static stretching and dynamic exercises have no statistical effect on sprint, slalom dribbling, and penalty kick performance. This conclusion supports the hypothesis that a combination of static stretching and dynamic warm-up exercises can reduce the detrimental effects of static stretching on sprint, slalom dribbling, and penalty kick performances. With this study, evidence relating to dynamic warm-up exercises is superior than static stretching applications for preparing activities that required high power production such as sprint, slalom dribbling, and penalty kick. Besides, it has been observed that known detrimental effects of static stretching application can be reduced partially with combined static stretching and dynamic exercise (Method D).

In this study, as a result of sprint, slalom dribbling, and penalty kick test performed after 5-minute jogging and the static stretching exercises performed after this warm-up practice, there occurred a decrease of 8.5, 4.1, and 2.1%, respectively. This result supports those of the previous studies showing that static stretching exercises decrease the power and speed performance (11,18,22,24,29).

Siatras et al. (29) asserted that static stretching practice performed before the activities requiring maximal power performance decreases peak torque by 8.5-16%. Holt and Lambourne (18) showed the negative effects of static stretching practice performed after general warm-up on vertical jump performance in their study carried out on 64 football players. In the same vein of this study, Little and Williams (22) investigated the acute effects of different warm-up protocols including static stretching exercises on high-speed motor capacities in professional soccer players and observed meaningful decreases in sprint performance after static stretching practice. Similar findings showing that static stretching exercises decrease sprint performance were asserted by Nelson et al. (24) in their study conducted on track athletics and by Fletcher and Jones (11) in their study conducted on rugby union players. On the other hand, in regard to maximum power production, the researchers asserted that static stretching prevents one-repetition maximum (1 RM) knee extension and flexion (20), maximum isokinetic torque moment (25,36), and vertical jump performance (4,31).

The mechanism responsible for the acute decrease in power and speed observed after static stretching exercises is still indefinite. But researchers have tried to explain the negative acute effect of static stretching on performance with the changes in the neuromuscular transmission and biomechanical characteristics of muscle (2,20,21,34). Kubo et al. (21) suggested that static stretching makes the muscle tendon more compliant by changing its biomechanical structure and therefore causes delays in muscle activation by decreasing power production. This change of muscle stiffness is very important for techniques such as sprint, slalom dribbling, and penalty kick used in this study. Kokkonen et al. (20) asserted that when compared with a compliant MTU, a stiff MTU leads to a better transmission of the power produced during muscle contraction. Wallmann et al. (32) and Avela et al. (2) supported this point by documenting the decrease in electromyography excitability during muscle contraction after static stretching practice. Wilson et al. (34) proposed that for concentric muscle activities, a stiffer system optimizes the properties of its contractible components such as muscle length and contraction rate, increases the power production capacity and specifically places them in a better position on power-speed and power-length curves in muscle contraction in terms of power production. In this study, static stretching exercises performed by soccer players after general warm-up may have negatively affected sprint, slalom dribbling, and penalty kick performance by preventing lower extremity muscle groups from working when they are in a suitable position on power-speed and power-length curves.

One of the probable mechanisms is that after stretching in joint proprioceptors (golgi tendon organs), muscles may form inhabitation as reflex on muscles and synergists. Knudson et al. (19) state that parallel to the results of this study, static stretching practice affects vertical jumping performance negatively. Because they could not determine expressive differences in movement kinematics after static stretching practice, they suggested that the negative effect observed in vertical jump performance depends on the decrease in neural transmission. They bring to a conclusion of acute neural transmission inhibition caused by, in other sense, neural excitation that goes to the muscles decrease. According to Rosenbaum and Henning's (27) studies, there may be a relationship between the decrease in observed power production after static stretching and neuromuscular factors. This symptom supports the neurological definition of performance decrease caused by stretching. These findings support the neurological explanation of the performance decrease caused by stretching.

The findings of this study shows that dynamic exercises performed after 5 minutes of jogging positively affect sprint, slalom dribbling, and penalty kick performances and thereby power performance. In our study, it is found that as a result of sprint, slalom dribbling, and penalty kick tests performed after jogging and of the static stretching exercises performed after this warm-up practice, there occurred a difference of 4.4, 5.1, and 3.3%, respectively (p < 0.05). This result supports those in previous studies showing that dynamic exercise increases the power and speed performance (8,11,31). Faigenbaum et al. (8) investigated the acute effects of different warm-up protocols on anaerobic performances of the teenage athletes on whom the study was conducted. They stated that dynamic warm-up and combined static stretching and dynamic warm-up practice positively affect sprint, medicine-ball toss, and vertical jump performance. Thompsen et al. (31) indicated that for jumping performance, the use of warm-up exercises is more exercisable by sportsmen because of their positive effects when compared with cycling and static stretching exercises. Faigenbaum et al. (7) documented as a result of their study in which they evaluated the acute effects of different warm-up protocols on fitness performances that moderate- to high-intensity dynamic warm-up exercises activate high power performance. Again, Faigenbaum et al. (9) encountered no meaningful association in medicine-ball toss or 10-yd sprint performances although they documented that warm-up exercises increase vertical jump and broad jump in female high-school athletes.

Although more researchis needed in this field, it can be said that dynamic exercise performed for warm-up purposes may increase explosive-power production increasing neuromuscular functionality. This phenomenon is called “postactivation potentiation” (PAP) (28). Despite the mechanisms initiating PAP still being under examination, the existing theories show that there may occur chemical, neuromuscular, and mechanical changes that may temporarily help contractile properties of muscular tissue (13,14,28). Besides the mechanisms behind potentiation, the previous studies showed that the particulars of the person, such as training status or fibril type distribution, may determine the ability of PAP to appear (14,16,28). In addition, certain research studies showed that fast-twitch muscles affect certain activities such as sprint because fast-twitch muscles show higher potentiation than do slow-twitch muscles (14,16). Young et al. (35) used 1 set of 5 RM squat loading in their studies and found that there occurred an increase of 2.8% in jump height. Güllich and Schidtbleicher (14) reported that as a result of pretest high-intensity MVC, there occurred an increase of 3.3% in vertical jump height. Gourgoulis et al. (12) found that as a result of many increasing intensity half squats, the jumping performance improved by 2.4%. In the aforementioned studies, they asserted that dynamic loading contractions performed before activities requiring high power such as vertical jump stimulate the central nervous system and these exercises allow an explosive effort to be made.

It can be suggested that as used by us in our study, the dynamic warm-up exercises performed after 5 minutes of jogging increase the excitability of speed-contracted units of target muscles and thereby make these units ready to play an important role during certain activities such as sprint, slalom dribbling, and penalty kick.

Another finding of this study is that a combination of static stretching and dynamic exercises performed after 5-minutes of jogging has neither a positive nor negative effect on sprint, slalom dribbling, and penalty kick performance. This conclusion has indicated that known detrimental effects of static stretching can be reduced partially with a combination of static stretching and dynamic exercises after 5-minutes of jogging. When the studies, the research protocol of which includes a combination of static stretching and dynamic exercises, are examined, it is seen that the results are actually conflicting (8,10,33). Wallmann et al. (33) reported, in a similar vein to our research results, that a combination of static stretching and dynamic activities applied on gastrocnemius muscle has neither a positive nor a negative effect on vertical jump performance. Fletcher and Anness (10) documented in their studies that static passive stretch combined with active dynamic stretch and static dynamic stretch combined with active dynamic stretch protocols decrease 50-m sprint performance. Faigenbaum et al. (8) observed that as a result of a pre-event combination of static stretching exercises and dynamic exercises, a meaningful increase in vertical jump, medicine-ball toss, and 10-y sprint is observed. As is seen, the results of the studies are conflicting. This conflict is expected to be solved by future studies on combination of static stretching and dynamic exercise.

Practical Applications

Data in this study indicate that in soccer players, static stretching applied to lower extremities after 5-minutes of jogging reduces sprint, slalom dribbling, and penalty kick performances. This conclusion does not imply which soccer players should be removed from fitness programs. Simply, it is important for soccer trainers to know about the potential effects of static stretching application before the competition on performance. In this study, it was observed that in soccer players power production after 5 minutes of jogging increases with dynamic exercise. Application of PAP which was caused by dynamic exercises for increasing the athletic performance seems to be a potential area for future research. As a reason for performance reducing the effect of static stretching, the use of dynamic exercises is recommended before activities such as sprint, slalom dribbling, and penalty kick. Alternatively, soccer players can apply both static stretching and dynamic exercises during warm-up. It should have been knowledge of detrimental effects of static stretching for performance, that it could be partially reduced with dynamic exercise combination of it, but this combination does not improve the performance. In conclusion, to succeed in sports based upon maximum power production, it is recommended not to apply static stretching exercises intended for the main muscles of a certain movement before the competition, instead dynamic exercises would result in being more accurate.

Acknowledgment

The author would like to thank all the dedicated soccer players and the team trainer for their participation.

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Keywords:

soccer; static stretching; dynamic exercise; power; potentiation

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