THE SPECIFICITY OF NEUROMUSCULAR PATTERNS IN SWIMMING ACTIVITIES
Sensory Organs in the Skeletal System
The brain senses movements through three forms of sensory input. Inputs from those mechanisms combine to form movement patterns in the movement areas of the cerebral cortex.
These three mechanisms provide the specific complexity of information about particular movements. They are the links between muscle movements and the brain's patterning of specific movement characteristics. The degree of sensitivity of this system of sensory organs is quite remarkable and it facilitates very refined movements if an individual is exposed to the appropriate learning and practice conditions. It is the uniqueness of the amount of information that is provided by particular movements that produces the specific nature of learning. Learning specificity is a survival mechanism because in a biological sense, it provides the basis for adaptation and for evolutionary development and existence. If an organism was not able to discriminate very minor changes in its internal and external environments, it would neither evolve nor survive. The body is oriented to discerning the differences between very similar movement patterns rather than generalizing common features.
The Specificity of Neuromuscular Patterns
The concept of all movement patterns being separate and specific has existed for a long time. In this day, little research is conducted on the patterning of movements in the brain. It has become an accepted motor learning principle that all movements are specific and that the higher the level of proficiency of an athlete, the more refined will be neuromuscular patterns. It is the neuromuscular patterns that govern high-level performance even in activities where physical effort is extreme (e.g., Grabe and Widule's 1988 study on weightlifting). As evidence of the universal acceptance of this concept, Luttgens and Hamilton (1997), in their valuable book on kinesiology, did not justify the principle of neuromuscular specificity in their discourse on throwing but simply referred to it as follows:
Skillful and efficient performance in a particular technique can be developed only by practice of that technique. Only in this way can the necessary adjustments in the neuromuscular mechanism be made to ensure a well-coordinated movement (p. 507).
The two authors repeated their acceptance of the specificity of neuromuscular patterning in their discussion of muscle strength.
Strength or endurance training activities must be specific to the demands of the particular activity for which strength or endurance is being developed. The full range of joint action, the speed, and the resistance demands of the movement pattern should be duplicated in the training activity (p. 465).
Many auxiliary training activities for swimming are advocated. They need to conform to this principle. Only a few works in the historical literature that lead to this principle will be considered here. While reading this treatise, one must consider how can the popular commercial activities that exist today (e.g., paddles, kick boards, resistance training, segment exaggeration, flippers) conform to this principle? If they cannot, then they must be wrong.
Some historical elements in the development of the specificity of neuromuscular patterning.
The most impressive early discussions (~90 years ago) mostly involved Frank Gilbreth's recount of Sperry's work, which disputed Poppelreuter's Law. That work showed when an arm was extended vertically downward and the index finger slowly traced a 12-inch circle, a pattern of sequential firing of the shoulder muscles was displayed with most muscles assuming a propulsive (agonistic) function at one time and a control (antagonistic) function at another. However, when the same circle-tracing was sped-up, the sequence and functions of all the muscles were totally changed despite an observer seeing the "same action" done at a faster velocity (Arthur Slater-Hammel, personal communication, October, 1967).Frances Hellebrandt (1958, 1972) summarized much of the main implications of the research on motor learning specificity that existed before the late 1950s. There has been little new information on this topic since then. Some of her conclusions and their implications are listed below.
"If muscles participate in more than one movement, as most do, they must be represented diffusely in the cortex. Presumably different centers connect via internuncial neurons with groups of peripherally disposed motor units. . . . motor units are activated in a definite sequence which varies with the movement elicited. As the severity of effort increases, those involved primarily in one movement may be recruited to assist in the performance of others" (Hellebrandt, 1972, p. 398).
Movement patterns, not muscles, are represented in the cortex. Patterns are learned and those patterns are peculiar to every movement. Skilled performance improvements are continual refinements of the details governing the skill intensity, velocity, and locus of movement. They are represented in the brain. No swimmer would learn to swim at an intended high-level race velocity without practicing at that race velocity. However, at lower levels of performance it is possible to train "somewhere near an intended performance", a procedure that sustains mediocre performances.
". . . reflexes evoked under similar conditions are extraordinarily consistent. Indeed, they are so repetitive as to warrant designating them patterned movements. . . the fundamental unit of action may be thought of as a total response in which agonists and antagonists, synergists and fixators participate in balanced and harmonious activity. Partial patterns emerge secondarily, by virtue of special training, . . " (p. 399).
Total actions (e.g., those to be used in a competitive setting) need to be practiced. The partial or isolated training of movement segments (e.g., drill, kicking, resistance training) would not replicate the unit function in the total action. Thus, once techniques (total response patterns) are being refined, partial practices will serve no purpose other than to learn another movement. There should be no integration of the partial practice movement into the total response movement once an individual-determined level of skill competency is reached. The only way a highly skilled swimmer can improve his/her swimming, is to practice specific swimming velocities. No auxiliary training activities will contribute to skill enhancement once the skill has achieved a reasonable level of proficiency.
". . . the sensory feedback coming from muscles, tendons, and joints greatly affects movement patterns. Central excitations have a tendency to flow always into stretched muscles. Thus, every change in body positioning alters the configuration of the next succeeding efferent response. It affects not only the muscles stretched, but all functionally related muscle groups as well. This means that a change in the responsiveness of one component of a movement-complex spreads autonomously to the other constituents" (p. 399).
When a patterned movement is changed by conscious effort to alter at least one aspect of a movement, the whole action is altered, usually to perform worse. The practices of isolated drill elements and then consciously implementing the experiences from the drills into the established pattern will disrupt the pattern in its entirety. Thus, the changed element may be performed "better" but the other, previously acceptable movement characteristics will be altered for the worse. This is the conclusive argument against auxiliary training that is supposed to "strengthen" a swimmer, or increase swimming velocity. Claims to produce beneficial changes in swimmers by doing something other than swimming should be treated with great skepticism.
". . . willed movements which are new and unfamiliar always demand cerebration. They are performed at first with more or less conscious attention to the details of their execution. Once mastered, they operate automatically. Conscious introspection at this stage may even disrupt the nicety of an established pattern. After an act has become automatic, . . , it is less well performed if it must first be considered and analyzed" (pp. 399-400).
Conscious attention to details of an automated action will reduce the efficiency/economy of that action. There is a time before a contest when conscious attention to details of technique at practice need to cease so that preparation can be perceived by a swimmer as consisting of "good feeling" techniques that are performed automatically. At some stage in a swimmer's career, the emphasis should switch from "changes for the better" to refinement of established skills. That is why high levels of skill development have to be achieved in swimmers by the stage of maturity. When refinement is approached, it should involve mental preparation and recognition, specific skill practice, and evaluation of swimmer-generated feedback against objective feedback (e.g., video analysis).
If many like movements are learned, conscious attention in a race could switch to a less-efficient pattern of movement, particularly if attention is on one segment of the skill. As attention then switches to other different features, the economy of a performance is degraded. In races, and at practices, a great deal of emphasis should be placed on the total skill. If change is desired, then skill segments will have to be changed requiring both the coach and swimmer to endure and tolerate a decline in performance until the change is incorporated successfully and the whole altered pattern, which is a new skill, is practiced sufficiently to surpass the level of learned performance of the previous form of the skill. With young people, altering established skills is possible. However, with mature individuals there comes a time when no alterations of established skill patterns should be contemplated because there would be insufficient practice time to successfully incorporate the change and return to or better the previous performance level.
However, when fatigue is incurred, conscious attention to performance details produces a more efficient movement form than one that is executed automatically. Thus, there are times when the conscious control of performance movements is detrimental (e.g., in non-fatigued states) and times when it is beneficial (e.g., in states of high fatigue). In swimming, a loss of control or technique should be used as the index of detrimental fatigue, recognizing that the fatigue could be physical, neural, mental, or combinations of all three.
Through practice, many activity patterns are learned. More often than not, families of movement patterns are learned to accomplish the same functional outcome. While a task is executed, movement patterns will be evoked in series to avoid unnecessary fatigue in the central nervous system mechanisms and the skeletal structures used. In fatigue and stress, the recruitment of extra responses and neural patterns will be more extravagant because of learned facilitation. Much training is performed in fatigue and thus, more than restricted efficient movement patterns are learned to dominance. This constitutes one part of the "danger" of using equipment and drills in intense training. If specific limited training had only occurred, that is, the body only knew a narrow band of efficient movements (and not the patterns associated with drills, flippers, paddles, etc.), then the recruitment (irradiation) would be minimal and movement patterns would center on efficient movement. Adequate rests during practice should be provided to prevent the swimmer trying very hard to perform well when tired because too much fatigue inhibits the attainment of practice goals, reduces learning potential, and sensitizes the brain to new experiences and neural representations.
Practice does not make perfect. Only practice that yields feedback about the correctness of responses can generate advances towards perfection. If practice activity content is largely irrelevant for competitive requirements and/or feedback is inadequate or non-existent, practice time largely will be wasted. However, individuals without external correct-coaching feedback do improve in performance but only to a certain level. Without instruction, individuals tend to adopt expedient strategies for movement control, which quite often are not the best or most economical movement patterns. This is why an individual can play golf for 40 years, never have a golf lesson, and struggle to break 90 for 18 holes. The expedient patterns that have been learned and perpetuated limit performance to that of a mediocre level.
For efficient and maximum performance ". . . the kinesthetic acuity we should strive for is not enhanced general body awareness, but rather, a more sharply defined and specific sensitivity to what is happening in those key maneuvers upon which the success or failure of complex movement patterns may depend" (Hellebrandt, 1972, p. 407).
The skill content of practices has to mimic that of competitive requirements if beneficial training time is to be experienced. It is wrong to practice something with good intent (e.g., "I hope it will benefit the performance") without being able to justify and demonstrate correlated transfer to a competitive skill. It is wrong to practice swimming if the skill amplitude and rate do not reflect the intended race-specific qualities (Robb, 1968). If this dictum is not adhered to, much practice will be wasted or even will be counter-productive. It is quite possible that movements practiced could be so irrelevant that their impact on hoped-for competition-specific movements will be so destructive that performance will be worse than if no practice had occurred.
Specificity in sports conditioning and practices is a contentious topic. Many coaches, and those who should know better, advocate the generality of sporting activities through concepts such as cross-training, drill practices, resistance skill activities, and even diets. These concerns are not evidence-based and yet they persist and flourish to the detriment of a swimmer's progress. This is difficult for many coaches to accept as it is contrary to their established beliefs, the perpetuated myths of the sport, and the activities embraced by the majority of coaches in swimming. It is one area where many commercial ventures not subjected to "truth in advertising" restrictions have exploited a market of na�ve but well-intentioned customers.
In so advocating the specificity of training, the following qualifications are offered.
This seeming contradiction has to be understood by coaches. It indicates that very young swimmers, need to experience variety in skills and conditioning activities. Early specialization has been shown to be counter-productive to long-term development in sports (Borms, 1986a, 1986b). However, once a swimmer has sufficient experience and skill level, the Principle of Specificity (Rushall, 2003b; Rushall & Pyke, 1991) dominates the capacity to learn and the direction for appropriate conditioning and skill development.
Violations of the Principle of Specificity in swimming training continue to be embraced. Unfortunately, this was a common phenomenon observed in Carlile Swimming environments. It is not difficult to discern in the culture of swimming coaching that additions to its folk lore are easily accepted because of a lack of accountability and verification in the occupation. Add to that an arrogance of opinion and one must be skeptical of almost all things advocated as being valuable coaching principles in the sport.
To conclude this central theme of developing, improving, and increasing consistency in a cyclic motor skill such as swimming, the following quote from one of the world's most foremost motor learning/control scientists, Dr. Richard Schmidt, author of Motor learning and performance: From principle to practice is most pertinent.
A common misconception is that fundamental abilities can be trained through various drills and other activities...For example, athletes are often given various 'quickening' exercises, with the hope that these exercises would train some fundamental ability to be quick, allowing quicker response in their particular sport. There are two correct ways to think of these principles.
First, there is no general ability to be quick, to balance, or to use vision...Second, even if there were such general abilities, they are, by definition, genetic and not subject to modification through practice...A learner may acquire additional skill at a drill...but this learning does not transfer to the main skill of interest" (Schmidt, 1991, p. 222).
The specificity of movement patterns and control is a scientifically established principle of human exercise. There has been no wavering on this scientifically validated phenomenon over the past century, although minor theoretical incursions have been attempted. Yet, swimming practitioners persist in violating this basic principle of performance with dubious arguments, false premises, and distortions of facts. It is too well proven to concede that the scientists might be wrong. It is time for the practices and programs of swimming coaches to be brought into line with what is established fact. The training of swimming skills and their variants has to be specific and whole. The programming of appropriate transferable-to-race practice activities in an enriched milieu of correct swimming instruction and conditioning is a challenge for modern swimming coaching.
REFERENCES
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