Exercise / Testing performed with a Biodex that provides variable resistance to a movement, so that no matter how effort is exerted, the movement takes place at a constant speed. Such exercise is used to test and improve muscular strength and endurance, especially after injury.

Isokinetic Resistance Mode*

The Isokientic resistance mode for testing and rehabilitation is totally accommodation throughout the entire range of motion. Biodex's unique impact free acceleration and deceleration eliminated joint trauma, allowing patients to exercise and be tested at more functional speeds. Resistance continuously matches effort, accommodating to variations in patient force output due to weakness, pain or fatigue at specific points in the individual’s range of motion. Research along with over 25 years of clinical application has demonstrated that isokinetic resistance is a safe, objective, means to quantify physical impairments with high correlation to function. Isokinetic testing is the standard for muscle and joint assessment. Applied torque response ensures that the patient's limb velocity increases or decreases in proportion to the torque applied during acceleration and deceleration, enabling neuromuscular control measurements.

Reactive Eccentric Mode*

The reactive eccentric mode for submaximal neuromuscular re-education in the early phase of rehabilitation. The Biodex responds only to the patient's force output. To initiate movement, the patient must produce and maintain a pre-determined minimum amount of force. This loads the muscles surrounding the joint, producing a pre-load, thus stabilizing and protecting the joint.

Passive Motion Mode*

The passive motion mode is a multi-function modality. Using control properties allows for early intervention in all patients throughout all phases of rehabilitation. If a torque limit is exceeded during an eccentric contraction, the Biodex stops. Once the patient's torque output drops below the prescribed limit, movement is allowed. This unique capability allows patients to work safely at definitively prescribed sub-maximal force levels while combining isometric, concentric and eccentric contractions for:


  • Decreasing joint effusion
  • Increasing range of motion
  • Developing strength


The very slow speeds allow for overcoming the natural stretch reflex which is ideal for proprioceptive testing in the early stages of rehabilitation. Higher speeds in passive mode are ideal for active assistive exercise.

Isometric Mode*

The isometric mode is commonly used pre and post operatively or when pain associated with motion is a factor. Isometric contractions are effective at developing strength and decreasing joint effusion while avoiding painful points in the range of motion. Work the agonist, antagonist or both muscles at specified joint angles.

Muscle Isotonic Mode*

The isotonic mode allows velocity to vary while providing inertia-free constant force and concentric or eccentric muscular contractions. Higher performance. Ideal for work simulation. Constant force muscle loading is considered functional, as natural activities normally involve moving constant weight object at varying velocities.

* As stated on the Biodex Isokinetics Website