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Adaptation Through Exercise


Adaptation through exercise is a key principle of kinesiology that relates to improved fitness in athletes as well as health and wellness in clinical populations. Exercise is a simple and established intervention for many movement disorders and musculoskeletal conditions due to the neuroplasticity of the brain and the adaptability of the musculoskeletal system. Therapeutic exercise has been shown to improve neuromotor control and motor capabilities in both normal and pathological populations.

There are many different types of exercise interventions that can be applied in kinesiology to athletic, normal, and clinical populations. Aerobic exercise interventions help to improve cardiovascular endurance. Anaerobic strength training programs can increase muscular strength, power, and lean body mass. Decreased risk of falls and increased neuromuscular control can be attributed to balance intervention programs. Flexibility programs can increase functional range of motion and reduce the risk of injury.

As a whole, exercise programs can reduce symptoms of depression and risk of cardiovascular and metabolic diseases. Additionally, they can help to improve quality of life, sleeping habits, immune system function, and body composition.

Finally, the study of the physiologic responses to physical exercise and their therapeutic applications is known as exercise physiology, which is a major research focus within kinesiology.

Neuroplasticity


Neuroplasticity is also a key scientific principle used in kinesiology to describe how movement and changes in the brain are related. The human brain adapts and acquires new motor skills based on this principle, which includes both adaptive and maladaptive brain changes.

Adaptive Plasticity

Recent empirical evidence indicates the significant impact of physical activity on brain function; for example, greater amounts of physical activity are associated with enhanced cognitive function in older adults. The effects of physical activity can be distributed throughout the whole brain, such as higher gray matter density and white matter integrity after exercise training, and/or on specific brain areas, such as greater activation in prefrontal cortex and hippocampus. Neuroplasticity is also the underlying mechanism of skill acquisition. For example, after long-term training, pianists showed greater gray matter density in sensorimotor cortex and white matter integrity in the internal capsule compared to non-musicians.

Mal-Adaptive Plasticity

Maladaptive plasticity is defined as the neuroplasticity with negative effects or detrimental consequences in behavior. Movement abnormalities may occur among individuals with and without brain injuries due to abnormal remodeling in central nervous system. Learned non-use is an example commonly seen among patients with brain damages, such as stroke. Patients with stroke learned to suppress paretic limb movement after unsuccessful experience in paretic hand use; this may cause decreased neuronal activation at adjacent areas of the infarcted motor cortex.

There are many types of therapies that are designed to overcome maladaptive plasticity in clinic and research, such as constraint-induced movement therapy (CIMT), body weight support treadmill training (BWSTT) and virtual reality therapy. These interventions are shown to enhance motor function in paretic limbs  and stimulate cortical reorganization   in patients with brain damages.

Motor Redundancy
Motor redundancy is a widely-used concept in kinesiology and motor control which states that, for any task the human body can perform, there are effectively an unlimited number of ways the nervous system could achieve that task (ref). This redundancy appears at multiple levels in the chain of motor execution:


 * Kinematic redundancy means that for a desired location of the endpoint (e.g. the hand or finger), there are many configurations of the joints that would produce the same endpoint location in space.
 * Muscle redundancy means that the same net joint torque could be generated by many different relative contributions of individual muscles.
 * Motor unit redundancy means that for the same net muscle force could be generated by many different relative contributions of motor units within that muscle.

The concept of motor redundancy is explored in numerous studies (ref), usually with the goal of describing the relative contribution of a set of motor elements (e.g. muscles) in various human movements, and how these contributions can be predicted from a comprehensive theory. Two distinct (but not incompatible) theories have emerged for how the nervous system coordinates redundant elements: simplification and optimization. In the simplification theory, complex movements and muscle actions are constructed from simpler ones, often known as primitives or synergies, resulting in a simpler system for the brain to control (ref). In the optimization theory, motor actions arise from the minimization of a control parameter, such as the energetic cost of movement (ref).