Discover proven isokinetic exercise examples with objective data tracking. Enhance rehab protocols with techniques, equipment guidelines, and measurable outcomes.
For decades, isokinetic exercise has been a research and rehabilitation tool to assess and challenge muscle groups. It’s a valuable yet often overlooked method that offers therapeutic benefits beyond muscle strength. Isokinetics can be a useful tool in a clinician’s toolkit to help facilitate safe, confident discharge or successful return to sport.
Let’s review what isokinetic exercise is and go over some examples. Then, we’ll discuss its benefits, drawbacks, and practical tips for application in the clinic.
Isokinetic Exercise: Definition and Examples
Isokinetic exercise is a type of training that keeps the movement speed constant through the range of motion, regardless of how much force the patient applies. Isokinetic exercises can also train concentric or eccentric muscle contractions, depending on the patient’s strength deficits and goals.
The most traditional isokinetic training method uses a specialized machine (dynamometer) to isolate movements, guide the patient through the range of motion, and collect data. A rehabilitation professional monitors the machine and cues the patient while the machine controls the movement’s speed at a preprogrammed rate. Once the exercise is done, the machine calculates the patient’s strength, which can be used as a baseline or re-evaluation assessment. It can also be used as part of training if it’s relevant to the patient’s goals.
Examples of isokinetic exercise with a dynamometer include:
- Concentric-concentric testing of knee flexion and extension
- Concentric-eccentric testing of elbow flexion
- Eccentric-eccentric testing of hip abduction and adduction
How Isokinetic Exercise Compares to Other Types of Exercise
Isokinetics is just one of three types of strengthening. Each type has its own constant.
- Isotonics: Fixed resistance and muscle tension through a movement
- Isometrics: Fixed muscle length in one position
- Isokinetics: Fixed velocity through a movement
Isotonics are the most commonly used type of exercise because this mode is the most functional. It mimics real-life applications the most closely, allowing you to train patients in the same manner that they perform tasks in daily life. Bicep curls, weighted squats, and picking up your toddler are all examples of isotonic movements.
Isometrics are also a useful modality, especially in the context of gym exercise. Isometric exercise involves applying force to an unmoving object or surface. Think planks and wall squats, where you hold one position for 30–60 seconds. Adding date capture and objective measurement of the force applied makes isometrics very useful for evaluating a patient’s strength.
Isokinetics are not as common in everyday therapy because it’s difficult to control speed without specialized equipment, and isokinetics are traditionally performed isolating one joint (often the knee). Some may consider treadmill walking or biking at consistent revolutions per minute as an isokinetic exercise, but not in the traditional sense. As we know, using an isokinetic dynamometer is best way to achieve isometric movement.
While some clinics see value in a single-purpose isokinetic device, a multifunctional system like the PrimusRS delivers far greater clinical versatility. With all three resistance modes—isotonic, isometric, and isokinetic—built into one unit, therapists can match the modality to each stage of a patient’s treatment program, ensuring the right approach for strength building, stabilization, or controlled speed-based training and testing.
Key Benefits of Isokinetic Exercise
Research has established many benefits of isokinetic assessment and exercise since its rise in the late 1960s. Below are some of the most significant.
- Reliable and consistent data: Isokinetic systems can test the same patient using the same procedure each time, providing consistent data points throughout rehabilitation compared to manual muscle testing. Not only can this data help guide rehabilitation efforts, but it can also confidently justify continued treatment when necessary.1
- Isolated testing: These machines can isolate a specific movement and/or muscle group to determine strength. For certain injuries, isolated testing is key to determining if an athlete can return to play. A common example is post-ACL surgery, where the quadriceps, hamstring, and glute strength on the affected limb should be at least 90% of the opposite side . Testing each side independently allows you to make sound clinical decisions based on objective comparative data from limb to limb.1,2
- Applications in performance: Isokinetic exercises can be performed quickly and intensely. This improves performance-boosting factors like muscle power and rate of force development, which can be applied to return-to-sport therapeutic activities.1
- Built-in motivation: Systems often have built-in feedback or real-time data displays for the patient to see how they’re performing. They get to see their “score” history and try to beat it with every attempt.1
A Few Drawbacks
As with most modalities, there are also some drawbacks to isokinetics. If you don’t have a dynamometer, isokinetic tests and exercises are not able to be administered reliably or consistently. Therapists will also experience a learning curve when first using a dynamometer machine. This includes swapping equipment pieces for corresponding limbs and learning the software. Look for a system from a reliable company that has been in business for some time, and provides consistent clinical support and video guides on how to perform setups to get your clinicians up and running fast.
One perceived drawback is a lack of functionality. In fact, the rise of functional rehabilitation caused a decline in isokinetic exercise popularity for some years. Many view whole-body, compound movements using the isotonic modality in functional task simulation as more relevant than isolated movements.
But some recent research disagrees, stating that isokinetic testing and exercise are highly relevant in sports injury rehabilitation. Athletes are returning to sport with residual strength and power deficits—factors that isokinetics address well. Integrating isokinetic testing and exercise along with functional training may help reduce rates of reinjury and improve post-rehabilitation performance .1,3
That’s where the PrimusRS comes in, giving you the power of isotonics, isometrics, as well as isokinetics in one system. Complete with an array of attachments to simulate a variety of functional activities of daily living (ADLs), industrial applications, or sports, as well as fine motor movements of the hand.
Who Should Use Isokinetic Exercise?
Anyone can use isokinetic exercise, although some populations have more established benefits than others.
Injured Athletes or Post-Op Patients
One example we’ve briefly discussed is a patient post-ACL surgery. Not only can isokinetic systems assess strength baselines, but they can also help establish milestones in muscular balance compared to the opposite limb for sport clearance. And according to a 2023 study from Wang et al., adding isokinetic muscle strengthening to rehabilitation improves knee flexor and extensor strength and endurance, kinaesthesia, and position sense—all of which have functional implications for return to sport .1,4
Isokinetic Testing for Return to Sport
Benefits exist at the upper extremity, too. Isokinetic testing and training are useful tools in assessing and strengthening the shoulder complex, but functional carryover may look different. A study by Choi et al. determined that isolated shoulder exercises, as you may see using traditional isokinetic dynamometers, have less functional improvement than core-shoulder chain isotonic exercises (or exercises that involve core activation with shoulder complex activation).5 Luckily, the PrimusRS system has versatile attachments that allow therapists to replicate functional activities and involve other muscle groups using isotonic as well as isokinetic training methods.
Another example is post-total knee arthroplasty (TKA). Research from Cheng et al. suggests that incorporating isokinetic training during early rehabilitation post-TKA can help improve functional outcomes (in this case, the timed up-and-go) better than isotonic and isometric exercise alone in the span of four weeks.6 The key takeaway here is that more variety and versatility are better. This study recommends an integrated approach of isokinetic in conjunction with isotonic training to see optimal improvement in functional outcomes and strength gains.6
Older Adults and Patients At Risk of Falls
A similar integrated approach is also beneficial for elderly patients who are at risk of falls or those with multiple comorbidities affecting balance. This population may have more mobility and strength limitations that influence exercise choice, but isokinetic exercise on a machine could be safe and effective when paired with activity-specific training.
One study from Kay et al. found that incorporating eccentric isokinetic exercise into a multifaceted treatment program of hip, knee, and ankle musculature significantly increases mobility, strength, and muscle thickness, which remained after eight weeks of detraining. A case study from Beebe et al. also suggests taking a combined approach using both isokinetic strengthening and a balance program to improve fall risk .7 Again, isokinetic is not a silver bullet, but it is a powerful tool when used as part of a comprehensive program.
Fall-risk patients often need very gradual progression with exercises that do not strain the joints. For gentle lower extremity strengthening to improve stability, the Eccentron provides continuous eccentric isokinetic exercise throughout the range of motion. Combining the isokinetic movement with eccentric-only resistance creates a very gentle exercise that supports strength, stability, and control to reduce the risk of falls.
Patients With Neuromuscular Conditions
Research also suggests that isokinetic exercise benefits those with neuromuscular conditions or disease. Pontes et al. published a review analyzing 13 studies, which found that isokinetic training improved muscle strength, mobility, and gait speed for patients post-stroke.
A study by Dibble et al. found that high-intensity isokinetic eccentric exercise on the Eccentron produced gains in muscle growth and functional abilities in Parkinson’s patients.8 The Eccentron’s gamified sessions requires the patient to focus on controlling their resistance with every rep to stay inside the target force range. This instant visual feedback promotes neuromuscular control during isokinetic movement that is essential for neurorehab.
Practical Tips: Safety and Documentation
Below are a few safety considerations and documentation tips that can help you use isokinetics successfully in the clinic.
Safety Considerations
No matter how hard a patient contracts a muscle, the movement’s speed stays the same (when using a dedicated isokinetic machine), which helps prevent joint or muscular injury. Exercising sound clinical judgment tailored to every patient’s needs is always important. Coaching the patient not to over-exert, ensuring biomechanics are correct, and providing continuous monitoring and feedback are critical when using any rehab system.
Therapists should be fully trained, understanding how to lock moving pieces, position the patient, and program appropriate settings specific to the patient (like range of motion and resistance parameters). This allows the therapist to mitigate against malfunctions, errors, joint stress, and muscle strain.
Documentation
Documenting isokinetic tests and exercise seems tricky, but it doesn’t have to be. Here are a few considerations for making documentation easy and consistent for internal use and insurance review.
- Create a templated note for all therapists: Isokinetic systems have many variables to document. Use a set formula every time an isokinetic test or assessment is performed, so all therapists note the same protocol structure for consistent retesting or re-administration. For example, a clinic may develop a template that lists the speed, sets, reps, type of contraction, movement, range of motion, and rest time.
- Connect isokinetic exercise to functional goals or surgeon protocol: If a patient is post-ACL surgery and needs to meet muscle balance requirements in their protocol for return to sport, explicitly connect their isokinetic testing results to their previous baseline assessments and functional goals.
- Always document why a skilled therapist is needed: Highlight that isokinetic exercise requires specialized knowledge to adjust speed, range of motion, and resistance for safety and efficacy.
- Use accurate codes: Isokinetics can be used for multiple reasons, but always apply the correct CPT code for the activity. If an isokinetic system is used to test and assess strength, use a testing and measurement code. If it was used for treatment, use therapeutic exercise or neuromuscular re-education. With a multimodal functional rehab system like the PrimusRS, you can also bill therapeutic activity if you perform a movement that closely mimics an ADL or sport.
Check out the Clinician’s Guide to Physical Therapy CPT Codes for Maximum Reimbursement.
Conclusion
Isokinetic systems and dynamometers can help safely measure objective data, improve strength, and establish clearer benchmarks throughout rehabilitation. These machines offer accuracy and consistency between tests and exercises that manual testing can’t match. Plus, isokinetic training provides many evidence-based therapeutic benefits that can help patients reach their goals.
Isokinetics are just part of the complete picture in rehab. A multimodal treatment plan is critical to enhancing recovery. Remember to incorporate isometric testing for proper dosing and isotonic exercises for real-life functional task simulation as part of your approach. To deliver all of these benefits in one compact package, consider a multifunctional system like PrimusRS for your clinic. This advanced system will empower you to perform isokinetic tests and exercises in addition to functional movements to help your patients get back to their lives with lasting outcomes.
Nicole Hernandez, PT, DPT earned her doctorate in physical therapy from Campbell University. She worked in an outpatient orthopedic setting for several years before transitioning to a full-time career in health writing. Now, she contributes articles and educational content to clinics, hospital systems, and healthcare organizations across the United States, helping clinicians and patients make informed decisions about their care.
