Training the Vertical Jump to Head the Ball in Soccer

0 downloads 0 Views 518KB Size Report
a soccer player, and more specifically, vertical jump height is ... free segment and that the arms had little role in ..... Methodology, performance, prediction, and evaluation ... football. Part 2: Biomechanics of ball heading and head response. Br J.
Training the Vertical Jump to Head the Ball in Soccer Antonio Paoli, BSc, MD,1,2 Antonino Bianco, PhD,3,4 Antonio Palma, MD,3,4 and Giuseppe Marcolin, PhD1 Department of Human Anatomy and Physiology; 2Human Movement Sciences School, University of Padova, Padova, Italy; 3Faculty of Sports and Exercise Sciences; and 4Department of Legal, Economic, Biomedical, Psycho pedagogic Studies of Sports and Exercise Sciences, University of Palermo, Palermo, Italy

1

SUMMARY IN MODERN SOCCER, HEADING THE BALL IS BOTH AN OFFENSIVE TOOL USED TO SCORE GOALS AND A DEFENSIVE MEASURE AGAINST OPPOSING TEAMS. PROFICIENCY IN HEADING THE BALL REQUIRES PROPER TECHNIQUE IN CONJUNCTION WITH AN EFFECTIVE VERTICAL JUMP. THE AIM OF THIS ARTICLE IS TO ADDRESS THE FACTORS INVOLVED IN VERTICAL JUMP PERFORMANCE AND HOW THEY RELATE SPECIFICALLY TO HEADING THE BALL.

INTRODUCTION: STRENGTH OR POWER?

esearchers involved in the training methodology to improve jump ability proposed a variety of techniques and exercise modalities (22,15,4). Nevertheless, the question on what percentage of training should be dedicated to strength and what to power seems unresolved. First of all, to better understand the matter, we have to stress the difference between strength and power. Generally speaking, in athletics, the rate of force development (RFD) is much more important than strength alone; the average RFD (mRFD) can be estimated as the ratio Fmax/Tmax, where Tmax is the time to reach the peak force, whereas Fmax is the maximum force. This ratio is also named explosive strength, commonly computed, for applicative purposes per 1 kilogram of body weight (26). Explosive strength is a fundamental conditional capacity for

R

80

VOLUME 34 | NUMBER 3 | JUNE 2012

a soccer player, and more specifically, vertical jump height is primal to successfully impact the ball. Explosive strength is fundamental for a soccer player to obtain the jump height necessary to head the ball or, in other words, the maximal ability of a muscle to exert force or torque at a specific velocity (16). This kind of neuromuscular quality is often assessed by the 1 repetition maximum (RM) test, but 1RM strength maybe useful only for a few athletic events like weightlifting because during the 1RM test, low acceleration values are usually obtained. Referring to concentric movements, the difference among strength and power generation is due to the velocity of the muscle contraction. In fact, power is given by the product of force and velocity: the higher the force, the lower the velocity of concentric muscle action (14). This is explained in Figure 1.

SOCCER JUMPING HEADER: TECHNIQUE AND TRAINING CONSIDERATIONS

This skill (Figure 2) begins with the loading of the leg (or both legs) in preparation for the jump, then the arms move from bottom to top, and the take off starts. At the beginning of the flight, the trunk and the legs extend backward; the further back the trunk extends, the greater the maximum forward velocity of the upper trunk and head. Force is produced by a strong contraction of the trunk flexors, hip flexors, and knee extensors before impact (20). After impact, the jumping header finishes the movement with the landing phase.

It is clear how take off is a key point to reach a consistent jump height and needs specific training. This phase is similar to a counter movement jump (CMJ) (with both legs or with a single leg depending on the game situation), where the muscles involved are first stretched and then shortened to accelerate the limb. As a consequence, storage of elastic energy in both muscle and tendon occurs, with a direct reutilization in the subsequent concentric phase, contributing to increase the jump performance (5). Another contribution to strengthen the concentric action is because of the increase of muscle neural stimulation elicited by the mechanical stretch stimulus (10,11). This action of the lower limb muscles, known as stretch-shortening cycle (SSC) (17), involves some interesting neural and mechanical processes extensively studied in the scientific literature (5,8,10,12,23). A second training point is the strengthening of trunk and hip flexors together with the knee extensors to obtain great trunk and head acceleration for a powerful ball heading. In addition, the complexity of heading the ball requests great degree of coordination. As a matter of fact, explosive strength depends on the level of intermuscular coordination considering agonist, antagonist, and synergist muscle activities. In fast movements, low levels of resistance should be recorded, and the relaxation of the antagonist muscles should be simultaneous and well coordinated with the agonist ones. In this KEY WORDS:

heading; soccer; vertical jump

Copyright Ó National Strength and Conditioning Association

Figure 1. Force/velocity and power relationship for skeletal muscle. Vm, maximal velocity; Pm, maximal power output; Fm, maximal isometric force output.

direction, specific training may reduce agonist-antagonist cocontractions, strengthening the coordination pattern and, as a consequence, the role of agonist and synergist muscles (23). Literature investigations on soccer heading concentrated mainly on biomechanical aspects. Kristensen et al. (20) investigated the segmental

characteristics in jumping headers with particular attention to the head’s velocity relative to the torso at impact along with the contributions of the upper and lower extremities (19). Results showed that the head accelerated relative to the torso throughout the impact phase as a nonrestricted free segment and that the arms had little role in creating high ball speed

after impact. The authors concluded that movement of the legs was the single most important factor in the skill. Because of the body jackknife movement around the pelvis, the authors suggest developing muscle strength in the stomach, back, and pelvis and to put no restrictions on head and arm movement to optimize the jumping header (20). Marcolin and Petrone (21) proposed a functional evaluation method considering the height of the jump, the ball velocity, and its angle after impact. In particular, they identified a maximum efficient heading elevation of the header related to the ball speed increments and to the correct ball angles useful to evaluate training effects during the season. Furthermore, they introduced an elevation index defined as the percent ratio between the jump elevation and the anthropometric height of each subject and correlated it with the ball velocity to classify a player’s ability to head high balls with high impact energy. Shewchenko et al. (24) developed biomechanical methods and a numerical model to investigate head impact response and the influence of heading technique. If the aim is to reduce impact

Figure 2. Jumping header technique. (a) Loading of the leg. (b) Take off and arms movement. (c) Trunk and legs backward extension. (d) Ball impact. (e) Beginning of landing. Adapted with permission from Marcolin and Petrone (21).

Strength and Conditioning Journal | www.nsca-scj.com

81

Training for Heading the Ball in Soccer

severity, their mathematical modeling suggested an increased risk of neck loads performing alternative techniques. TRAINING CONSIDERATIONS TO IMPROVE JUMPING HEADER PERFORMANCE

Bosco and Komi (5) studied the relationship between jump performance and stretch load application showing an increase of the jump height with an increase in the stretch load. This explains, for example, why in the drop jump, the performance improves with the increase of the drop height. On the other hand, a too high stimulus with excessive stretch loads lead to an inhibition of the muscle contraction because of the Golgi tendon organ reflex (10,23). It is noteworthy that nonathletes or athletes unaccustomed to intense SSC tasks may show better performance during a CMJ than during a drop jump, and often, their drop jump height could be lower than the squat jump (SJ) (23). It also appears logical that vertical jump performance improves more markedly after strength training in subjects with an initial low value (1) than in previously strengthtrained athletes (12). In addition, combined strength-power training seems to be more effective than power or strength training alone in recreationally

trained subjects (7). According to these results, it is clear that the ability to rapidly generate force is the major contributor to vertical jump height both in presence of SSC (CMJ) and in the absence of it (SJ) (6). For soccer players, both skills are important to be trained, allowing development of great levels of strength in short periods (Figure 3). Many scientists (11,3) demonstrated the importance of mRFD for explosive performance and that squat training with heavy loads (70–120% of 1RM) improves maximal isometric strength but not mRFD (13). Therefore, in soccer, intermediate loads should be preferred to the heavy ones to train lower limb force and power. To support this, recent data (2) showed that weightlifting and plyometric exercise have different effects on muscle activation, and knee and hip angle of soccer players, suggesting that weightlifting training might be more appropriate in the precompetition period improving vertical jump height via changes in power and technique (9), whereas the plyometric exercises should be preferred in the competition period. As reported in the description of the jumping header technique, trunk and hip flexors and also abdominals have an important role in giving speed to the impacted ball. The trapezius muscle group stabilizes the

Figure 3. Time and force relationship in experts and beginners. Experts develop higher levels of force in less time with respect to beginners.

82

VOLUME 34 | NUMBER 3 | JUNE 2012

head and trunk in preparation for ball impact (25). Therefore, weightlifting has an important role not only for the quadriceps but also in reinforcing the role of the trapezius muscle groups in heading the ball. For these reasons, in the preseason, training including crunches and jackknives should be taken into account (18). During the transition phase from precompetition to the competition period, plyometric exercises should be mixed with series of CMJs (also with single leg) with the arms free to move in such away to simulate a double or a single-leg soccer heading take off. The use of the ball is recommended to improve the coordination of the jumping heading and should be emphasized above all in the competition period, whereas in the precompetition, the main focus of the training should be to increase the strength and muscle power. An example of a periodized program for ball heading in advanced soccer players is illustrated in the Table and should be integrated with the other athletic and technical training sessions. CONCLUSIONS

The importance of jumping heading is well documented in the literature; a study across different soccer leagues indicated that players impact the ball more than 6 times per game (20). This skill can also determine the outcome of a match, considering that in the Japan and Korea Fe´de´ration Internationale de Football Association world cup, more than 20% of the goals were scored by headers (20). Vertical jump height, along with the ability to head the ball with power, is the key point for an efficient jumping heading. Vertical jump performance depends not only on lower limb level of strength but also on the rate at which they are able to generate force, on the contraction velocity, on the ability of SSC utilization, and on the degree of intermuscular and intramuscular coordination. The increase of strength obtained with traditional weight training appears to be effective to increase jump height only in athletes with low level of initial strength. With experienced well-trained athletes, programs should aim to improve RFD and muscle

Table Weightlifting training program for vertical jump improvement in soccer headers Preseason: Phase 1 (4 weeks) traditional lifting Day A

Day B

Day C

Day D

Bench press 4 3 8 RM*

Squat 4 3 8 RM

Lat pull-down 4 3 8 RM

Incline bench press 3 3 10 RM

Deadlift 4 3 8 RM

Seated row 3 3 10 RM

Biceps barbell curl 3 3 8 RM

Leg extension 3 3 10 RM

Triceps pull-down 3 3 8 RM

Technique of Olympic-style lifting; only barbell without added loads (snatch pull, clean pull, push press, push jerk, overhead squat, power clean, clean and jerk, snatch)

Biceps dumbbell incline bench 3 3 10 RM

Seated leg curl 4 3 8 RM

Triceps extension 3 3 10 RM

Jackknives 33 max

Shoulder press 3 3 8 RM

Vertical calf 3 3 8 RM

Lateral raises 3 3 10 RM

Jackknives 33 max

Crunches 33 max Precompetition: Phase 2 (4 weeks) traditional lifting and Olympic-style lifting

Strength and Conditioning Journal | www.nsca-scj.com

Day A

Day B

Day C

Power clean 5 3 5 RM

Clean pulls 5 3 5 RM (floor)

Snatch pulls (waist) 5 3 5 RM

Snatch pulls (knee) 5 3 5 RM

Push jerks 5 3 5 RM

Push press 5 3 5 RM

Bench press 4 3 6 RM

Squat 4 3 6 RM

Lateral pull-down 4 3 6 RM

Push press 5 3 5 RM

Stiff leg deadlift 4 3 6 RM

Overhead squat 4 3 6 RM

Competition: Phase 3 (4 weeks) Olympic-style lifting and plyometric training Day A

Day B

Clean and jerk 5 3 5 RM

Snatch 5 3 5 RM

Push jerks 5 3 5 RM

Squat jumps (30% 1RM) 5 3 5 RM

Drop jumps 3x8

Snatch pulls (waist) 5 3 5 RM Competition: Phase 4 (4 weeks) Olympic-style lifting and specific heading technique

Day A

Day B

Clean and jerk 5 3 3 RM

Snatch 5 3 3

Power clean 5 3 3 RM

One leg ball heading jumps 5 3 5

Drop jumps with ball heading 5 3 5

Two legs ball heading jumps 5 3 5

* RM = repetition maximum.

83

Training for Heading the Ball in Soccer

power output. Because of the multifaceted nature of the vertical jump, a multivariate training approach seems to be more effective with respect to a single approach because it provides various stimuli for the development of different athletic qualities. For this purpose, particularly interesting seems to be the combined training of traditional weight training with sprints and Olympic-style exercises performed in different periods of the competitive season. The proposal of plyometric exercises mixed with a series of CMJs with the arms free to move simulating a double or a single-leg soccer heading take off is helpful to link exercises focused on increased jump height with training to improve trunk/lower limbs coordination. Finally, a simplified video analysis method for a functional evaluation of the jumping headers considering some of the parameters presented in the literature (21) such as jump height, ball velocity, and the initial angle described by the ball trajectory would be useful in comparing the players classifying their ability in heading high balls with high impact energy and in evaluating training effects during the season.

Antonio Paoli is an assistant professor of Exercise and Sport Science at the University of Padova. Antonino Bianco is an assistant professor of Fitness and Human Performance at the University of Palermo. Antonio Palma is a professor of Human Performance at the University of Palermo.

84

VOLUME 34 | NUMBER 3 | JUNE 2012

Giuseppe Marcolin is a postdoctoral research fellow at the University of Padova.

REFERENCES 1. Adams K, O’Shea JP, O’Shea KL, and Climstein M. The effect of six weeks of squat, plyometric and squat plyometric training on power production. J Appl Sci Sports Res 6: 36–41, 1992. 2. Arabatzi F, Kellis E, and Sae`z-Saez De Villarreal E. Vertical jump biomechanics after plyometric, weight lifting, and combined (weight lifting + plyometric) training. J Strength Cond Res 24: 2440–2448, 2010. 3. Behm DG and Sale DG. Velocity specificity of resistance training. Sports Med 15: 374–388, 1993. 4. Bo¨hm H, Cole GK, Bru¨ggemann GP, and Ruder H. Contribution of muscle series elasticity to maximum performance in drop jumping. J Appl Biomech22: 3–13, 2006. 5. Bosco C and Komi PV. Mechanical characteristics and fiber composition of human leg extensor muscles. Eur J Appl Physiol 24: 21–32, 1979. 6. Bosco C, Tihanyi J, Komi PV, Fekete G, and Apor P. Store and recoil of elastic energy in slow and fast types of human skeletal muscles. Acta Physiol Scand 116: 343–349, 1982. 7. Cormie P, McCaulley GO, and McBride JM. Power versus strengthpower jump squat training: Influence on the load-power relationship. Med Sci Sports Exerc 39: 996–1003, 2007. 8. Ettema GJC, Van Soest AJ, and Huijing PA. The role of series elastic structures in prestretch-induced work enhancement during isotonic and isokinetic contractions. J Exp Biol 154: 121–136, 1990. 9. Garhammer J. A review of power output studies of Olympic and powerlifting: Methodology, performance, prediction, and evaluation tests. J AppI Sport Sci Res 7: 76–89, 1993. 10. Gollhofer A and Kyroelaeinen H. Neuromuscular control of the human leg extensor muscles in jump exercises under

various stretch-load conditions. Int J Sports Med 12: 34–40, 1991. 11. Ha¨kkinen K. Neuromuscular and hormonal adaptations during strength and power training. J Sports Med 29: 9–26, 1989. 12. Ha¨kkinen K, Komi PV, and Ale´n M. Effect of explosive type strength training on isometric force- and relaxation-time, electromyographic and muscle fibre characteristics of leg extensor muscles. Acta Physiol Scand 125: 587–600, 1985. 13. Ha¨kkinen K, Komi PV, and Tesch PA. Effect of combined concentric and eccentric strength training and detraining on force-time, muscle fiber and metabolic characteristics of leg extensor muscles. Scand J Sports Sci 7: 65–76, 1991. 14. Hill AV. The heat of shortening and the dynamic constants of muscle. Proc R Soc Lond B 126: 136–195, 1938. 15. James RS, Navas CA, and Herrel A. How important are skeletal muscle mechanics in setting limits on jumping performance? J Exp Biol 210(Pt 6): 923– 933, 2007. 16. Knuttgen HG and Kraemer WJ. Terminology and measurement in exercise performance. J AppI Sport Sci Res 1: 1–10, 1987. 17. Komi PV. The stretch-shortening cycle and human power output. In: Human Muscle Power. Jones NL, McCartney N, and McComas AJ, eds. Champaign, IL: Human Kinetics, 1986. pp. 27–39. 18. Kotzamanidis C, Chatzopoulos D, Michailidis C, Papaiakovou G, and Patikas D. The effect of a combined high-intensity strength and speed training program on the running and jumping ability of soccer players. J Strength Cond Res 19: 369–375, 2005. 19. Kristensen LB. Investigation of segmental characteristics in powerful soccer heading. ISBS Symposia 2002. Caceres, Spain, 2002. pp. 409–412. 20. Kristensen LB, Andersen TB, and Sørensen H. Optimizing segmental movement in the jumping header in soccer. Sport Biomech 3: 195–208, 2004. 21. Marcolin G and Petrone N. A method for the performance evaluation of jumping headers in soccer. ISBS Symposia July 14-18, 2006. Salzburg, Austria, 2006.

22. McCaulley GO, Cormie P, Cavill MJ, Nuzzo JL, Urbiztondo ZG, and McBride JM. Mechanical efficiency during repetitive vertical jumping. Eur J Appl Physiol 101: 115–123, 2007. 23. Schmidtbleicher D. Training for power events. In: Strength and Power in Sport. Komi PV, ed. Oxford, United Kingdom: Blackwell Scientific Publications, 1992. pp. 381–395. 24. Shewchenko N, Withnall C, Keown M, Gittens R, and Dvorak J. Heading in football. Part 2: Biomechanics of ball heading and head response. Br J Sports Med 39(Suppl 1): i26–i32, 2005. 25. Sunami S and Maruyama T. Motion and EMG analysis of soccer-ball heading for the lateral direction. Football Science 5: 7–17, 2008. 26. Zatsiorsky VM. Biomechanics of strength and strength training. In: Strength and Power in Sport. Komi PV, ed. Oxford, United Kingdom: Blackwell Scientific Publications, 2003. pp. 439–487.

Strength and Conditioning Journal | www.nsca-scj.com

85