Motor Control

Motor control is a broad term that describes the general ability of a person to initiate and direct muscle function and voluntary movements. Motor control is a concept that is distinct from the many involuntary muscle actions of the body, such as shivering when cold or flinching when an object is directed at a person without warning. A related expression, "motor skills," refers to the ability to perform specific physical movements; motor control is also the acquisition and development of a series of distinct motor skills.

Motor control is divided into two subsets. Gross motor control is the ability of a human to move a large muscle group or segment of the anatomy; the waving of an arm is an example of this type of movement. Fine motor control is the ability to manipulate precise movement, such as handwriting. All motor control is an integrated product of three aspects of the human anatomy: muscles, bones, and the central nervous system.

The voluntary motor system, also known as the somatic nervous system, is the structure that permits and creates motor control. The system takes its name from the part of the brain known as the motor cortex, from which the signals to initiate movement originate. The impulse from the motor cortex travels along pathways through the brainstem into the spinal cord. The nerve cells of the spinal cord connect to a vast and intricate network to control the skeletal muscle movement. Motor neurons, the specialized mechanisms that communicate to the muscles, are a continuation from the nerve roots that branch out from each vertebra in the spinal column to the muscle over which control is required. There are a number of pathways essential to the function of the voluntary motor system, of which the pyramidal system is the best known and the most extensive.

The voluntary, or somatic, motor system that provides the body with motor control is in contrast to the autonomic system, which begins with the regulation directed by the distinct regions of the brain, including the hypothalamus. The hypothalamus regulates the function of many of the essential bodily systems, including heart rate, blood pressure, and electrolytic balance. The hypothalamus communicates much of its direction to these involuntary structures by way of the chemical signals, hormones, that are directed to the glandular network headed by the thyroid gland.

Every healthy person will be capable of both gross motor control and fine motor control. In many sports, athletic success is measured in the fine distinctions between athletes in terms of their coordination (particularly their hand-eye coordination), balance, and overall body control. Many aspects of motor control are hereditary; others are linked to the body type of the individual. As an example, a 5 ft 10 in (1.7 m) point guard on a basketball team is expected to be able to execute complex physical movements, such as dribbling the ball with either hand at full speed under defensive pressure. The 6 ft 10 in (2 m) basketball forward is not likely to be able to move with the same grace and speed as the guard. With practice, the taller and less coordinated athlete could achieve improvements in this particular skill, but it is unlikely that he or she could surpass the smaller and quicker player.

Body type and heredity aside, all athletes have the capacity to improve their motor control through the practice and the repetition of distinct motor skills. In many sports, the drills that form the basis of improved motor control ability are collateral to the sport itself. Cross training techniques are often employed to enhance a particular motor ability that is desired for a sport in an athlete. A notable example is the use of jumping rope in sports such as boxing; the repeated coordination of the athlete's footwork and hands in the act of skipping improves the athlete's overall coordination. American football has a time-honored training technique where players are required to move at full speed while negotiating a series of tires placed in a pattern; this drill builds the ability of the body to coordinate a jump vertically with a movement laterally to avoid falling into the obstacle, a non-contact simulation of the agile movements required on the playing field.

"Muscle memory" is a muscular attribute linked to the development of motor skills. When an athlete is sidelined from an activity due to injury, the athlete will return more quickly to his or her previous level of motor ability due to the memory preserved in the nervous system as to how the motion stressed the subject muscle or structure.

Competitor at Monster Jam freestyle motocross event.

A physical injury to any aspect of the voluntary motor system will impair motor control. A concussion or damage to the spine or spinal column is a frequent cause of such injuries. When a nerve becomes pinched or otherwise damaged through trauma, such as a carpal tunnel nerve fracture in the wrist, the pathway for the major nerve ending into the muscles of the hand, there will be similar limitations of movement.

Motor control can be significantly impaired though stresses imposed on other bodily systems. When athletes become dehydrated, they will commonly sustain an imbalance in their electrolyte levels, particularly that of the mineral sodium. A sodium deficiency will impair the ability of a nervous system transmission to be communicated to the working muscle.

SEE ALSO Hormones; Nervous system; Sport performance.