Professor Estélio Henrique Martin Dantas

• Mestre em Educação Física (UFRJ) e em Educação (UERJ)

• Doutor em Treinamento Desportivo (UERJ)

• Livre Docente em Educação Física (UFF)

• Pós-doutoramento em Psicofisiologia (UGF) e em Fisiologia (UCAM)

• Professor Titular do Programa de Pós-graduação Stricto Sensu em Ciência da Motricidade Humana da Universidade Castelo Branco

• Professor Colaborador da Faculdade de Motricidade Humana / Universidade Técnica de Lisboa (Portugal) e da Universidad Católica de San Antonio de Murcia (Espanha)

• Autor dos livros "A Prática da Preparação Física", "Flexibilidade, Alongamento e Flexionamento" e "Pensando o Corpo e o Movimento".

• Membro do American College of Sports Medicine e do European Group for Research into Elderly and Physical Activity

FLEXIBILITY TRAINING IN COLLECTIVE SPORTS

Brazilian teams of collective sports, specially that one of soccer, volleyball and basket- ball (masculine and feminine) have been attaining expressive victories in world and Olympic championships. Such a success is certainly due to the ethnic and cultural background of the Brazilian population, to the climate that allows outdoor training during the whole year and other conjunctural factors. In relation to specific field training, two factors distinguish the Brazilian and the American teams: the utilization of a type of planning of training based on the Russian developed technique of periodization (MATVEIEV, 1990; ZAKHAROV, 1992) as well as the way of facing and training flexibility. This last factor is, however, the only differentiating factor in relation to the European teams.

Flexibility defined by Holland (1986) and cited by ALTER (1988, p.3) as the physical quality responsible for ..."the wide extension of the available movement in one articulation or group of articulations". This definition could be complemented as: "The physical quality that is responsible for the voluntary performance of a movement at a maximum angular extension by an articulation or group of articulations, in the morphological limits, without the risk of provoking injury." (DANTAS, 1995, p.33).

If we talk about flexibility we refer to the largest possible arches of movements involved in articulations. Since sport practice requires the total utilization of articulation arches specifically involved in sport movements, it is very difficult, or sometimes, impossible, to reach a high rentability, without owing a good flexibility level in the muscles involved.

The higher the performance requirement is, the bigger the attention with flexibility there must be. This doesn't mean reaching the most possible mobility. Flexibility, opposite to all other physical qualities, is not the best or the bigger. There is an excellent flexibility level for each kind of sport and for each person, according to the requirements that the practice will have on the locomotion system and the structure of its components (ligaments, articulations, muscles and other structures involved).

A flexibility above the desirable level, will increase the risk of dislocation, besides preventing performance improvements, and not reducing the risk of muscular distention. (DANTAS, 1995, p. 51; KRIVICKAS & FEINBERG, 1996 and TWELLAAR, VERSTAPPEN, HUSON & VANMECHELEN, 1997).

High rentability training is based on the Scientific Principles of Sport Training (DANTAS, 1995, p. 37-54). It couldn't be different with flexibility. The text of the following paragraphs only enhances the necessity of taking into account the content of two of the cited principles:

To work on flexibility of the high performance athlete, trying to obtain the maximum results with the minimum risks, it is necessary to have a n extremely wide knowledge of the three involved factors: the biological characteristics of the athlete, the specific sport requirements and the physiological and methodological foundations of the flexibility.

Methodology of Flexibility Training

The intensity used in the training will stablish different requirement levels on the physical parameters, provoking different effects. So, when the intensity of the stimulation varies, the way of working as well as the effect on the organism will change. Chart 1 presents some examples :

CHART 1: Influences of the Training Intensity on the Kind of Obtained Effect

The logic of the different ways of work related to different intensity levels, results in the necessity of establishing differences between the maximum and sub-maximum way of flexibility training. So, the sub-maximum work will be called stretching and the maximum flexibilizing. Alter (1996, p.97), quoted DOHERTY (1971), indicating that one can work-out the flexibility in two ways: stretching and overstreching.

Independently of the name we give, the important thing is to define the existence of two distinct forms of working-out the flexibility, with the characteristics presented in Chart 2.

CHART 2: Differences between Stretching and Flexibilizing

The flexibilizing as we have seen, is stricto sensu, the form of flexibility training (maximum requirement). It can be developed in three ways: through static insistences (passive method), through dynamic and ballistic insistences (Active Method) and the Proprioceptive Neuromuscular (Facilitation Method).

It is important to emphasize that the differentiation factor between stretching and flexioning is exclusively the intensity and not the speed of the execution or the structure of the locomotion system that is pre-affected. Chart 3 presents the above statement.

Chart 3: Differentiating Factors between Stretching and Flexibilizing

Active Methods (Or Dynamic Flexibilizing)

The Active Methods imply the performance of dynamic exercises, which due to the inertia of the physical part, results in a moment of ballistic nature, provoking the work on the limiting structures of the movement. Each muscle must be submitted to three or four series of 10 to 20 repetitions each one, alternated by relaxing movements.

The execution of the maximum extension movements in speed, stimulates the muscular spindle, resulting in the miotatic reflex or stretching reflex. This reflex provokes the contraction of the muscles that are being stretched. Due to this proprioceptive reaction, in this type of flexibilizing, the limiting structure of the movement is usually the antagonist muscles and, especially, the elastic serial components ( part of the fascias of the conjunctive tissue that are localized between two muscle fibers and between them and the tendon) of the cited muscle groups. These methods emphasize, through this way, the muscular elasticity.

In the last decade, some Russian scholars have been testing a new process of realizing this method (ISSURIN, LIEBERMANN & TENNEBAUM, 1994), that consisted of a vibrating stimulation of the muscle (44 Mz, with 03 mm amplification). The effects of this methodology, although superior to the classic application, are inferior to those ones obtained through proprioceptive neuromuscular facilitation.

The counter-indication of these methods is due to the repeated traction to which the elastic serial components and the tendons are submitted, capable to reduce the support of the respective physical segment and even indicating the possibility of a mini-compromising of the explosive force (MAGNUSSON, SIMONSEN & KJAER, 1996; TAYLOR, DALTON, SEABER & GARRETT, 1990).

Passive Method (or Static Flexibilizing)

To use this method, one should slowly reach the normal limit of the joint arch of the athlete(limit between stretching and flexibilizing), force softly beyond this limit, wait for 6 seconds and force again, trying to reach the broadest possible arch of the movement. In this point the joint arch should be maintained for 10 to 15 seconds (Dantas, 1995, p. 75). This routine should be repeated for three to six times, with a relaxation time between them. The objective of this method is to increase the flexibility through the priority increasing of the joint mobility.

Several professionals insist in recommending longer stretching periods than those indicated above, based on vague personal experiences, without the necessary scientific background. Scientists that studied the subject, keep the indicated time periods. BORMS, VAN ROY SANTES & HAENTJENS (1987), indicate as a n ideal insistence time 10 seconds and came to the conclusion that 20 to 30 seconds time are unnecessary. Already MADDING, WONG, HALLUM & MEDEIROS , (1987), comparing the effects of insistences of 15, 45 and 120 seconds, came to the conclusion that there isn't any advantage of using insistences longer than 15 seconds.

The isometric tension provoked by the static insistence to which the muscle is submitted, acts on the Golgi tendinuous organ, provoking the relaxation of the agonist muscles, being the joint the limiting factor of the movement. Since this structure supports all the force that is being executed, it adapts itself, increasing the extensibility of the soft tissues and reducing this way its stability. This phenomena shows that the passive method for the training of flexibility of the articulations subjected to shocks in the contact sports is not indicated. (McNAIR & STANLEY, 1996).

Proprioceptive Neuromuscular Facilitation Methods (PNF)

The processes that use PNF for the training of flexibility are the most efficient processes (ALTER, 1988, p. 89; GOLDGES, MacRAE, LONGDON, TINBERG & MacRAE, 1989; MASSARA & SCOPPA, 1995; SURBURG & SCHRADER, 1997). Originally from the Kabat studies (1952), quoted by DANTAS, 1995, p.76), initially realized with therapeutic objectives, the PNF principles were used by Holtz (1967, Op. Cit.) to develop the Scientific Stretching for Sport (3S). From that process on many others appeared, of which the main are shown in Chart 4.

CHART 4: Effects of the Main Processes of PNF

It can be observed that each one of the methods have a specific application that indicates its utilization in a specific context, causing variable grave problems, in the case a wrong decision is taken.

FLEXIBILITY AND PERIODIZATION

The main determining factor in the choice about the flexibilizing method to be used, will be the necessity of the increase of flexibility as explained before. This effect will be obtained, mostly , due to the increase in the joint mobility or in the muscular elasticity.

The stability of the articulations that are subjected to shocks in the contact sports must be preserved by emphasizing the increase of the muscular elasticity in detriment of the joint mobility. The opposite effect is desirable for the training of the flexibility of muscle groups that need to support a physical segment or that will present explosive contractions during the performance.

Respecting these basic requests, we come to the conclusion that the training of the flexibility of an athlete will apply distinct methods for each considered physical segment, according to the kind of sport he is training for.

The choice of the adequate flexibility training will also be directly influenced by the time of periodization that is being considered. As we know the macro-cycle must be divided into three periods, for training objectives: preparation, competition and transition.

In the preparation period there will be two phases - the basic one, with the characteristic of general training; and the specific one, when the athlete realizes the transfer of abilities and capacities necessary for the competition. In the end of this period, the athlete must own all necessary items to reach sport victory.

In the competition period, the athlete receives a "polishing", the "fine adjustment" necessary for the performance. In this period he won't need to acquire nothing else in terms of training. He will only have to maintain what he has learned in the former period.

Finally, in the transition period, the athlete will be taken to a n active relaxing, to regenerate himself for the next macro-cycle. Although there won't be any technical requirements and he will be far from the usual environment of training, his accomplishment process won't stop, and the acquisition of his basic physical qualities will be emphasized, while recovering himself physically and psychically.

The training order of the flexibility along the macro-cycle, can be observed in Chart 5:

CHART 5: Flexibility Training Methods to be Used Along the Periodization

To determine which movements need a bigger extension and how much flexibility is needed, the athlete must own each of them. The physical coach, as well as the technical commission in the phase of the ante-project of the training in the pre-preparation period, determines in which sport movements which flexibility physical quality must be present and which is the necessary extension for a n excellent performance.

It is important to stress that during the training the athlete must own a n articulation arch 20% higher than the performance requires, so that he is able to perform each of the sport specific movements, without any unnecessary muscular effort.

Such statement can be easily understood with the following explanation from DANTAS, 1995: ;

The last 10 to 20% of the joint arch are characterized by showing a bigger resistance to the movement, due to the fact that he is reaching the limit of the muscle stretching, ligaments and other conjunctive tissues involved. So, every time this zone of high resistance (ZHR) is reached, the person will be obliged to have an extra effort, beyond that one normally required for the execution of the movement. In the case it is necessary to execute movements of large extension, one must be sure to have a safety margin of at least 20% beyond the joint arch to be used. This preoccupation will reduce the energetic strain of the athlete (p. 48).

CONCLUSION

Once the movements that need a good flexibility are chosen, which training methods should be applied and which extension for each of these arches is suitable, the physical coach will prepare exercise routines that will be daily used, so that they can be memorized by the athlete and so that during the psychologically stressing pre-agonist period, he can execute the correct stretching procedures automatically.

It is important to remember that the flexibility, although it is not a n important priority physical quality in the performance, when compared with power, speed and resistance, is present in almost all kinds of sports. This is why it is surprising that it is the least studied physical quality. This fact can explain why its training is much more influenced by believes and habits than by scientific knowledge.

The present study tried to give the coach subsidies that would help him choosing the best type of flexibility training, based on the background of the physiology and biophysics, and not on usual practices or guessing postures.

To try to search for a scientific way of improving our way of acting is a sound habit that each professional should pursuit. As Churchill said: "Only fools learn exclusively from their own experience".

BIBLIOGRAPHY

ALTER, Michael J. Science of stretching . 2nd. ed. Campaign: Human Kinetics, 1996.
ANDERSON, B. & BURKE, E.R. Scientific, medical, and practical aspects of stretching. Clinics in Sports Medicine. Philadelphia, v. 10, i. 1, p. 63-68, 1991.
BORMS, J.; VAN ROY, P.; SANTENS, I. & HAENTJENS, A. Optimal duration of static stretching exercises for improvements of coxofemural flexibility. Journalof Sports Science. London, v. 5, i. 1, p. 39-47, 1987.
DANTAS, Estélio H. M. Flexibilidade, alongamento e flexionamento. 3a ed. Rio de Janeiro: Shape, 1995. ____________ . A prática da preparação física. 3a ed. Rio de Janeiro: Shape, 1995.
GODGES, J. J.; MacRAE, H.; LONGDON, C.; TINBERG, C. & MacRAE, P. The effects of two stretching procedures on hip range of motion and gait economy. The Journal of Orthopaedic and Sports Physical Therapy. Malibu, p. 350-357, March 1989.
ISSURIN, V.; LIEBERMANN, D.G. & TENENBAUM, G. Effect of vibratory stimulation on maximal force and flexibility. Journal of Sports Sciences.London, v. 12, i. 6,p. 561-566, 1994.
KRIVICKAS, L. S. & FEINBERG, J. H. Lower-extremity injuries in college athletes - relation between ligamentous laxity and lower-extremity muscle tightness. Archives of Physical Medicine and Rehabilitation. Philadelphia. v. 77, i. 11, p. 1139-1143, 1996.
MADDING, S.W.; WONG, J.G.; HALLUM, A. & MEDEIROS, J.M. Effect of duration of passive stretch on hip abduction range of motion. Journal of Orthopaedic and Sports PhysicalTherapy. Baltimore, v. 8, i. 8, p.409-416, 1987.
MAGNUSSON, S.P.; SIMONSEN,E.B. & KJAER,M. Biomechanical responses to repeated stretches in human human hamstring muscle in vivo. American Journal of Sports Medicine. Waltham. v.24, i. 5, p.622-628, 1996
MASSARA, G. & SCOPPA, F. Proprioceptive Muscle Stretching. Journal of the Council for Health, Physical Education, Recreation, Sport and Dance. Reston. v. 31, i. 2, 38- 43, 1995.
McNAIR, P. J. & STANLEY, S. N. Effect of passive stretching and jogging on the series elastic muscle-stiffness and range of motion of the ankle joint. British Journal of sports Medicine. Oxford, v. 30, i. 4, p. 313-317, 1996.
NORKIN, Cynthia C. & WHITE, D. Joyce. Measurement of joint motion: a guide to goniometry. 2nd. ed. Philadelphia: F.A. Davies, 1995.
SURBURG, P. R. & SCHRADER, J. W. Proprioceptive neuromuscular facilitation techniques in sports medicine - a reassessment. Journal of Athletic Training, Dallas, v. 32, i. 1, p.34-39,1997.
TAYLOR, D.C.; DALTON, J.D.; SEABER, A.V. & GARRETT, W.E. Viscoelastic properties of muscle tendon units. The biomechanical effects of stretching. American Journal of Sports Medicine. Columbus, v. 18, i. 3, p. 300-309, 1990.
TWELLAAR, M.; VERSTAPPEN, F. T. J.; HUSON, A. & VANMECHELEN, W. Physical characteristics as risk-factors for sport injuries - a 4-year prospective-study. International Journal of Sports Medicine, Stuttgard, v.18, i. 1, p. 66-71, 1997.
VIOLAN, M. A.; SMALL, E. W.; ZETARUK, M. N. & MICHELI, L. J. The effect of karate training on flexibility, muscle strength, and balance in 8 to 13-year-old boys. Pediatric Exercise Science, Champaign, v. 9, i. 1, p. 55-64, 1997.