The Sit-to-Stand (STS) movement can be described as the change in body posture
from a sitting to standing position. In more biomechanical terms, it can be defined
as a transitional movement to the upright posture requiring movement of the center
of mass from a stable to a less stable position over extended lower extremities. The
STS movement is an important skill because it is related to functioning and mobility,
and is a prerequisite for walking. The execution of the STS movement varies within
and between persons, because many factors influence the way how people perform
an STS movement, e.g. seat height, arm rests, feet position, age, and lower extremity
muscle strength. Literature indicates that also health condition, e.g. neuromuscular
disorders, joint disorders and stroke, can result in specific changes in the execution
of the STS movement