Involves the study of 

The acquisition of motor skills 

The Performance enhancement of learned or highly experienced motor skills

The reacquisition of skills following injury, disease, and the like

involves the study of 

how the neuromuscular system functions to enable coordinated movement

While learning a new skill

While performing a well-learned skill

Involves the study of: motor behavior from infancy to old age

Issues related to motor learning or motor control

Greater emphasis on growth and maturation

Tasks or activities that have specific goals to achieve (action goals)

require voluntary control over movements and body segments

Specific patterns of motion among joints and body segments