Mountain View

Physical Therapy and

Sports Injury Clinic, Inc.

CYBEX ISOKINETICS

SYSTEM

    Mountain View Physical Therapy is excited to offer our completely upgraded Cybex Isokinetics System.  We are utilizing the Cybex system for strengthening with our patients, joint testing and pre work screens.  Below you will find a more detailed explanation of isokinetic exercise and testing.

    The term isokinetics describes in which a body segment accelerates to achieve a pre-selected fixed speed against an accommodating resistance.  No matter how much force is exerted by the patient, segment velocity will not exceed the pre-selected speed.  As torque is produced in an attempt to overcome the pre-selected speed, resistance varies to exactly match the force applied at every point in the range of motion.  The amount of force applied by the patient can be measured and represented both numerically and graphically.

    Because isokinetic resistance accommodates perfectly to the patient’s torque output, the risk of overloading a tested joint is greatly minimized.  Any reduction in force output due to pain or weakness results in an immediate reduction of resistance.  This reduction is measured and graphed enabling the clinician to determine where in the range of motion a deficit exists.  Additionally, consistency of performance is reflected in the reproducibility of an individual’s torque curves.  Maximal efforts generally produce uniform curves, whereas sub maximal efforts may result in curves of variable shape and amplitude.

    Isokinetic testing can also be used to screen for functional deficits that may predispose individuals to injury.  Through the use of normative data, can correlate testing results with physical demands of specific populations, jobs and activities.  This may enable safe parameters for specific tasks to be defined.

    Isokinetics is the safest and most efficient method to load a muscle.  Because it employs a fixed speed and totally accommodating resistance, isokinetics provides several benefits not found with other forms of resistance exercise:    

	Most efficient use of muscle output – Unlike isotonics, which can load a muscle maximally at it weakest point, isokinetics is capable of loading a dynamically contracting muscle maximally throughout the range of motion.
	Reduced chance of overloading injury – The patient’s force output is the sole factor controlling the amount of resistance generated by the machine, so there is less risk of overloading the patient’s musculoskeletal system.
	Accommodation to pain and fatigue – When the patient encounters a difficult or painful point in the range of motion, he/she can respond with less force and the isokinetic device will immediately decrease the resistance accordingly.
	Full range of speed for testing and exercise – Because isokinetic equipment generally provides a wide range of speeds, the clinician can pinpoint specific deficiencies in high or low-speed torque output.  Rehabilitation programs can be designed to include a variety of selected speeds.
	Decreased joint compressive forces at faster speed – According to Bernoulli’s Principle, the faster the movement of a surface (articular surface) over a fluid (synovial fluid), the less the surface pressure will be.  Isokinetics allows the clinician to exercise patients at high speeds, which decreases compressive forces on a joint.
	Physiological overflow of strength – Research indicates that exercising at a particular speed increases strength not only at that speed, but also at lower (and possibly higher) speeds.
	Virtual elimination of ballistic movement – Newton’s first law of motion stated that a body continues in its state of rest or unified motion unless it is acted upon by an outside force.  With isotonics exercise, the constant resistance of the weight adds to the inertial force of a moving body segment.  With isokinetics, inertial forces are reduced because the resistance produced by the machine stops when the subject stops producing force.

    The benefits discussed above are just a few topics discussed by:  The Clinical Aspects of HUMAC NORM System User’s Guide.