PHYSIOLOGY OF MOTOR LEARNING
Hellebrandt, F. A. (1972). The physiology of motor learning. In R. N. Singer (Ed.), Readings in motor learning (pp. 397-409). Philadelphia, PA: Lea & Febiger.
"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." (p. 398)
Implication. Movements, not muscles, are represented in the cortex. Patterns are learned and those patterns are peculiar to every movement.
". . . 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)
Implication. Total actions (e.g., those to be used in a competitive setting) need to be trained. It is highly unlikely that partial or isolated training of movement segments will 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 will be no integration of the partial practice movement into the total response movement.
". . . 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 muscle 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)
Implication. When a patterned movement is changed by the conscious effort to alter one aspect of the movement, the whole action is altered, most likely to perform worse. The isolated practices of drill elements and then consciously implementing the experiences from the drills into the pattern, usually 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, presumably for the worse.
". . . 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)
Implication. 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 an athlete as consisting of "good feeling" techniques that are performed automatically.
If many like movements are learned, conscious attention in a contest could switch to a less-efficient pattern of movement, particularly if one item of the skill is attended to. As attention then switches to other different features, the economy of a performance is degraded.
However, when fatigue is incurred, conscious attention to performance details produces a more efficient movement form than one that is executed automatically because it is so fatigued. Thus, there are times when 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).
When work becomes fatiguing, or efficient neuromuscular patterns no longer can be maintained, recruitment of motor patterns and motor components occurs. Irradiation associated with extreme stress is so widespread in the recruitment process that a willed movement limited to a single appendicular joint may evoke action potentials in muscles located in all four extremities, the head and neck, and the trunk.
Through practice, many activity patterns are learned. More than not, families of movement patterns are learned to accomplish the same functional outcome. While a task is being 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, anything but restricted efficient movement patterns are learned to dominance. If specific limited training had only occurred, that is, the body only knew a narrow band of efficient movements, then the recruitment (irradiation) would be minimal and would center around efficient movement.
Practice does not make perfect. Only practice that yields feedback about the correctness of responses can generate advances towards perfection. If the activity content is largely irrelevant for competitive requirements and/or feedback is inadequate or non-existent, the practices will be wasted. There is no dispute that 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 forms. 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 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" (p. 407).
Implication. 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. If this dictum is not adhered to then much practice will be wasted or even 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 skill practice had been entertained.
The programming of appropriate transferable practice activities
in an enriched milieu of correct instruction is a challenge for
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