Physical Training Nov 2007
 
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Balance Training Programs for Soccer Injury Prevention

Pafis G., Ispirlidis I., Godolias G.

Department of Physical Education and Sport Science,
Democritus University of Thrace, 69100 Komotini, Greece


Please address to:

Dr Asimenia Gioftsidou,


Department of Physical Education and Sports Sciences


Democritus University of Thrace,


Campus


69100 Komotini, Greece


Tel: +302531039662, Fax: +302531039623


e-mail: agioftsi@phyed.duth.gr





Abstract

The purpose of the study was to compare 2 different balance-training frequencies in improving proprioceptive ability. Thirty eight professional soccer players, were randomly assigned into 3 groups: the A group, exercised with a frequency of 6 times per week, for 3 weeks, the B group exercised with a frequency of 3 times per week, for 6 weeks and the C group (control) had no balance training. All participants were evaluated with the use of an electronic stability system and of a wooden balance board before (pre test) and after the training period (post test). The results showed that both training groups improved their balance ability similarly despite the different frequency of the balance program. The authors proposed that balance training program can be applied in soccer players on a daily basis or at least 3 times per week, according to the demands of the training period.

KEY WORDS: Soccer players, proprioception, frequency of balance training.


Introduction

Soccer is one of the most popular sports and attracts many participants all over the world (Heidt, Sweeterman, Carlonas, Traub, Tekulve 2000; Soderman, Werner, Pietila, Engstrom, Alfredson 2000; Peterson, Chomiak, Graf-Baumann, Dvorak 2000). This huge participation though, leads to a substantial number of musculoskeletal injuries (Morgan, & Oberlander 2001). To prevent such injuries, rehabilitation specialists propose specific exercise programs like strengthening exercise programs to restore muscle imbalances, stretching exercise programs to decrease muscle stiffness, and balance exercise programs to improve proprioception (Caraffa, Cerulli, Projetti, Aisa, Rizzo 1996; Rozzi, Lephart, Sterner, Kuligowski 1999; Askling, Karlsson, Thorstensson, 2003).

Balance exercises aimed at improving proprioception train the brain to recognize the body's segment position every moment. Therefore, a balance exercise program will train proprioception pathways more effectively under competitive circumstances. Specifically, in order to prevent limb injuries, peripheral and central nervous system receptors (Hanney, 2000), mechanoreceptors within muscles, tendons, and ligaments have to be activated. Balance exercises seem to help this activation occur faster and more effectively (Sammarco, 1995). In other words, the goal of balance exercises should be to reduce the time between neural stimuli and muscular response (Zachazewski, 1996).

Furthermore, it is important that balance exercise programs improve proprioception not only during the rehabilitation phase, but also during the competition period. This means that balance improvement protects athletes from possible forthcoming injuries (Hoffman, & Payne, 1995).

Although many studies propose that these exercises can increase balance ability because of the injury rate reduction recorded (Caraffa et al 1996; Wedderkopp et al. 1999; Chong, Ambrose, Carzoli, Hardison, Jacobson 2001), there were no studies found which measuring balance parameters and their possible improvements after an application of a specific balance exercise program in professional male soccer players. Also, there have been no researchers examining the optimal frequency of applying these protocols.

The rationale for the present study is to compare two balance programs with different frequency of application for their effectiveness in improving proprioception of the lower limbs: a daily balance program that lasted three weeks or a program that was applied 3 times /week for a period of 6 weeks.


Methods

Experimental Approach to the Problem

Considering that there is always a need for improving proprioception through specific exercise programs, this study examines which balance exercise frequency would be more effective in improving balance ability: a) 6 times a week for a 3 week period (group A) or b) 3 times a week for a 6 week period (group B). In other words the two experimental groups followed the same protocol but in different exercise frequency. The group C that followed only the soccer training was settled as a control group. The control group was used in order to check if soccer training alone can improve balance ability significantly. The participants of the C group were informed that they will perform the same balance training program 2 months later (after the final balance measures). The main question of the study was, which one will be more effective in improving postural control and train the brain to recognize the segment position, the program which was applied daily for a 3 week period, or the other which was applied 3 times a week for a 6 week period.

Following written, informed consent from each player and clearance from the university human subjects committee, thirty-eight professional soccer players participating in the championship of the first Greek division, volunteered to participate in this study. The subjects had a mean age of 22.7 ±3.5 years, a mean weight 76.2 ±4.9, and a mean height of 1.79 ±6.36. None of the subjects were participating in any other physical activity except the soccer training and the balance training. Also, they were free from injury in their lower limb and had no mechanical or functional instability in their knee or ankle in that period, so they were participating in regular soccer training. According to the team physician they did not have any biomechanical abnormality and had no other balance training activity prior to and during the entire research period.

The testing equipment that was selected to evaluate the 3 groups were an electronic stability system (Biodex stability system), a wooden balance board with hemi-cylindrical bottom surface, and a stopwatch. Procedures were in accordance with ethical standards of the Committee on Human Experimentation at the Institution at which the work was conducted and with the Helsinki declaration of 1975.


Deviations from the horizontal plane

The subjects tried to maintain the unstable balance platform in the horizontal position. Any balance platform deviations where reported numerically by the system in degrees. More specifically, the system provides three different indices according to the direction of the deviations from the horizontal plane; the total stability index (SI), the anterior -posterior index (API) and the medial-lateral index (MLI).

The participants were tested in the stability level 1 (less stable) and performed three 20 sec practice trials and three 20 sec test trials out of which only the best score was recorded.


Balance boards tests

The balance board consisted of a flat wooden box 35 cm by 35 cm and 1 cm height in the middle of its under surface was located a hemi cylindrical hardwood block (35 length and 6 cm height).

The balance maintenance time of the subjects was recorded on the balance board with hemi-cylindrical bottom. They tried to maintain the board as stable (contact point only the cylinder) for as long as possible avoiding any contact of the board edges with the ground, performed one time for anterior –posterior free motion (placed the cylinder parallel to frontal plane), and the other time for medial lateral free movement (placed the cylinder vertical to frontal plane).

For each test trial, subjects were asked to stand on a single leg on the balance board with both arms across their chest and with the unsupported limb held in a comfortable position so as not to contact the test limb or the balance board. The subject’s chosen test position was used for all practice and data collection trials.

Their effort stopped when one of the edges of the board touched the ground. The participants performed three practice trials and three test trials out of which only the best score was recorded.

The 38 soccer players were randomly assigned in 3 groups, 2 experimental groups (13 participants each) undergoing the soccer training and the additional balance program and 1 control (12 participants) that followed only the soccer training. The testing procedure was followed by a training period for the 2 groups (by a training period of 3 weeks for the group A and of 6 weeks for the group B) and then the participants repeated the same testing procedures.

Description of the balance exercise program: The exercise program was designed using principles from elite athlete training programs and those designed for rehabilitation of injured athletes with functional instability of their ankles or rupture of the anterior cruciate ligament. The main goal while designing the exercise program was to include skills that improve awareness and knee control during standing, cutting, jumping and landing, which are important soccer technical elements. The balance exercises were performed both on the electronic stability system and on two wooden balance boards: one board with hemispherical bottom surface and the other with hemicylindrical bottom surface. All the exercises were performed randomly for each limb. The exercises that constituted the balance training program are described in table 1.

Table 1. Means (Μ) and standard deviations (± SD), for total (SI), anterior-posterior (API) and medial-lateral deviations (MLI).


Group Α

Group Β

Group C

Deviations

Pre-training

Post-training

Pre-training

Post-training

Pre-training

Post-training


Μ±SD

Μ±SD

Μ±SD

Μ±SD

Μ±SD

Μ±SD

SI dom

9,6±2,4

6,1±0,8*

9,0±2,2

7,6±1,6*

9,2±2,4

8,7±1,5

SI no-dom

8,1±2,5

6,2±2,4*

8,4±3,0

6,6±2,0*

8,5±3,1

8,6±2,1

API dom

7,7±2,3

5,6±1,1*

8,2±3,1

6,3±1,6*

8,1±3,3

8,1±1,5

API no-dom

6,9±1,9

5,3±2,1*

8,0±2,8

6,4±1,8*

8,4±2,9

8.2±1,9

MLI dom

4,9±1,2

3,7±1,0*

5,4±1,3

3,5±0,9*

5,3±1,5

5,2±0,8

MLI no-dom

4,4±1,2

3,3±1,2*

4,9±1,6

3,1±0,8*

4,7±1,4

4,8±0,9

* p<.05



Table 2. Means (Μ) and standard deviations (± SD), of the balance boards maintenance time for the total (T), anterior-posterior (APM), and medial-lateral movements (MLM).

Time (sec)

Group Α

Group Β

Group C


Pre-training

Post-training

Pre-training

Post-training

Pre-training

Post-training


Μ±SD

Μ±SD

Μ±SD

Μ±SD

Μ±SD

Μ±SD

TOTAL

2,6±1,6

5,3±2,4*

2,7±1,2

4,9±1,4*

2,8±1,4

2,9±1,4

APM dom

3,6±2,4

10,6±7,3*

2,5±0,7

9,6±3,1*

2,6±0,7

2,6±1,1

APM no-dom

3,0±1,6

7,1±2,2*

2,6±1,8

11,4±6,7*

2,8±1,8

2,4±2,1

MLI dom

2,7±1,6

15,2±8,1*

3,3±1,7

17,1±12,1*

3,3±1,7

3,1±1,1

MLI no-domi

3,0±1,6

17,8±7,8*

3,5±1,8

19,3±14,2*

3,5±1,8

3,3±1,2

* p<.05


Statistical analysis

A repeated measures Manova model was employed in order to determine possible statistically significant differences between the measurements and between the 2 experimental and control group.Statistical significant was accepted at p =< 0,05.


Results

The results revealed that the experimental groups showed a balance improvement in all tests, but the control group did not, meaning that both training programs were effective in improving balance. Tables 1-2 illustrate the means and standard deviations for the deviations and balance time for both limbs during the balance tests. More specifically, both experimental groups showed statistically significant performance improvement in balance ability evaluated on the Biodex Stability System (deviations from the horizontal plane) (p<.05). The performance improvement on the balance board tests was also significant (p<.05). Comparing the two experimental groups, the results showed that there was no significant difference in improving balance ability p>0.05.


Discussion

The results of this study showed that both balance training frequencies were effective in improving balance ability for both lower limbs, adding another important parameter in designing balance exercise programs. Although a lot of studies propose that these exercises can increase balance ability because of the injury rate reduction recorded (Caraffa et al 1996; Wedderkopp et al. 1999; Chong, Ambrose, Carzoli, Hardison, Jacobson 2001), there were no studies found measuring balance parameters and their possible improvements after an application of a specific balance exercise program in professional soccer male players.

More specifically, injury rate reduction on professional athletes after the application of balance exercise programs have been recorded by many authors. Caraffa and his partners (1996) in a prospective controlled study of 600 soccer players mentioned the positive effects of a specific balance-training program on the decrease of ACL injuries. This program had a graduated difficulty, and was applied on three hundred healthy soccer players (training group), 20 min per day, for three seasons. The results showed that the training group presented only 13% of the injuries of the control group. Similarly, Wedderkopp and his partner (1999) mentioned that the application of a balance training program on balance boards by healthy female hand ball players, for 10 months resulted in a decrease of frequency of lower limb injuries.

As regards the assessment of balance ability after an application of a specific balance exercise program there were studies performed not on professional athletes but on healthy people. Hoffman and Payne (1995), investigated the effects of ankle disk training (BAPS) on postural sway of healthy subjects (n=28) and showed significant improvements. They concluded that 10-weeks of proprioception ankle disk training can decrease postural sway parameters significantly. Chong and his partners (2001) also applied a balance program on healthy people using balance boards (4 weeks, 3 times per week). The program was carried out and the participants improved their balance ability.

As concerns the content of balance training programs applied to healthy athletes, it has been suggested that they should be adjusted to the peculiarities of each sport, simulating its activities (Tippett & Voight 1995). The design of the balance programs used in the present study is in accordance with the above theory. The specific balance exercises required the combination of balance ability and certain soccer skills, like kicking and headers. According to the present study design, both training groups performed the same exercises and although the frequency was different, their balance ability was equally improved.

In conclusion, the application of a 216-minute balance-training program can improve body control and increase proprioceptive ability. The daily balance program and the program with a frequency of 3 times per week had the same result in balance improvement. Therefore, the soccer - coach is able to select the appropriate frequency of balance exercise according to its own training schedule, knowing that the effectiveness is equal for both frequencies.


References


Arnold, B.L., & R.J. Schmitz (1998). Examination of balance measures produced by the Biodex Stability System. J Athletic Train. 33(4): 323-327.

Askling, C., J. Karlsson, & A. Thorstensson (2003). Hamstring injury occurrence in elite soccer players after preseason strength training with eccentric overload. Scand J Med Sci Sports. 13(4):244-250.

Biodex Stability System. Stability System, resource book. Shirley, New York, 1998.

Caraffa, A., G. Cerulli, M. Projetti, G. Aisa, & A. Rizzo (1996). Prevention of anterior cruciate ligament injuries in soccer. A prospective cοntrolled study of proprioceptive training. Knee Surg. Sports Traumatol. Arthrosc. 4(1): 19-21.

Chong, R.K., A. Ambrose, J. Carzoli, L. Hardison, & B. Jacobson (2001). Source of improvement in balance control after a training program for ankle proprioception. Percept. Mot. Skills. 92(1):265-72.

Hanney, W. Proprioceptive training for ankle instability (2000). Strength and Con. 22(5): 63-68.

Heidt, R.S., L.M. Sweeterman, R.L. Carlonas, J.A. Traub, & F.X. Tekulve (2000). Avoidance of Soccer Injuries with Preseason Conditioning. Am. J. Sports Med. 28:659-662.

Hoffman, M. & G. Payne (1995). The effects of proprioceptive ankle disk training on healthy subjects. JOSPT. 21(2): 90-93.

Morgan, B., & M. Oberlander (2001). An Examination of Injuries in Major League Soccer. Am. J. Sports Med. 29: 426-430.

Rozzi, S.L., S.M. Lephart, R. Sterner, & L. Kuligowski (1999). Balance training for persons with functionally unstable ankles. J. Orthop. Sports Phys. Ther. 29(8):478-486.

Sammarco, G.J. (1995). Rehabilitation of the foot and ankle. Mosby-Year Book, Inc. St. Louis, Missouri.

Soderman, K., S. Werner, T. Pietila, B. Engstrom, H. Alfredson (2000). Balance board training: prevention of traumatic injuries of the lower extremites in female soccer players± A prospective randomized intervention study. Knee Surg. Sports Traumatol. Arthrosc. 8:356-363.

Tippett, S., & M. Voight (1995). Functional Progressions for Sport Rehabilitation. Human Kinetics

Tropp, H., C. Askling, & J. Gillquist (1985). Prevention of ankle sprains. Am. J. Sports Med. 13:1259-1262.

Wedderkopp, N., M. Kaltoft, B. Lundgaard, M. Rosendahl, & K. Froberg (1999). Prevention of injuries in young female players in European team handball. A prospective intervention study. Scand. J. Med. Sci. Sports. 9:41-47.

Zachazewski, J., D. Magee, & W. Quillen (1996). Athletic injuries and rehabilitation. W.B. Saunders Company, pp. 236-261.




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Physical Training Nov 2007