Posturographic Characteristics of Eccentric, Isometric and Concentric Movements

Determine the posturographic characteristics of eccentric, isometric and concentric movements in healthy subjects as well as in subjects with chronic, orthopedic conditions / pain not involving the lower extremities. The squatting movement (going down from a stand up position, bending the ankle, knee and hip joints, and then returning to the stand up position, while not lifting the feet from the supporting ground surface) is a simple motion that involves all three types of movements: eccentric (the going down), isometric (holding the down position for a couple of seconds) and concentric (the coming up). It is hypothesized that non-healthy subjects will not have "smooth" movements, and posturography could be used to separate between healthy and non-healthy subjects.

Subjects will undergo Computerized Dynamic Posturography (CDP) testing using the modified Clinical Testing of Sensory Integration in Balance (mCTSIB) protocol: the subjects will be required to stand on a hard or compliant surface (a 4" tall foam cushion of known mechanical properties) in a comfortable posture, feet shoulder width, with eyes open or closed, head straight and arms to the side and free to move, gazing forward, and breathing normally. Subsequently, subjects will be asked to stand first on the right leg and then on the left leg, raising the other leg (flexing the hip about 45 degrees), bending (flexing) the knee 90 degrees, keeping the arms extended and moving them laterally (abduct shoulders to 45 degrees and extend both elbows) to help maintaining balance with eyes open. Finally, subjects will be asked to perform 10 repetition of the squatting movement, with the operator pacing them (telling them when to start and when to stop the movements). The results of the mCTSIB, combined with an initial physical and neurological examination will be used to classify the subjects into the healthy and non healthy group.

Subjects will undergo CDP testing using the modified Clinical Testing of Sensory Integration in Balance (mCTSIB) protocol. Subsequently, subjects will be asked to stand first on the right leg and then on the left leg with eyes open. Finally, subjects will be asked to perform 10 repetition of the squatting movement, with the operator pacing them (telling them when to start and when to stop the movements).

The Stability Score (calculated as percentage ratio of the actual sway and the theoretical limit of stability) will be used to investigate if there is any difference between healthy controls and subjects affected by chronic pain not involving the lower extremities. Statistical tools such t-tests and correlation coefficients will be used for assess if there is a difference between the two groups

The average velocity moment (calculated as as the product of sway velocity path length) will be used to investigate if there is any difference between healthy controls and subjects affected by chronic pain not involving the lower extremities. Statistical tools such t-tests and correlation coefficients will be used for assess if there is a difference between the two groups

The sway path length (the distance traveled during the test) will be used to investigate if there is any difference between healthy controls and subjects affected by chronic pain not involving the lower extremities. Statistical tools such t-tests and correlation coefficients will be used for assess if there is a difference between the two groups

The frequency content (calculated using FFT) will be used to investigate if there is any difference between healthy controls and subjects affected by chronic pain not involving the lower extremities. Statistical tools such t-tests and correlation coefficients will be used for assess if there is a difference between the two groups

Inclusion Criteria: subjects with chronic, orthopedic conditions / pain Exclusion Criteria: involving the lower extremities