Comparison with Alternate Treatments

Two Approaches to Mechanical Stretch:  Comparing Effectiveness

There are two engineering or biomechanical approaches that can explain home mechanical therapy that reflect different assumptions about how scar tissue behaves.  

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Use different engineering and stronger materials to deliver a lot more torque to the tissue. 

ERMI devices enjoy good patient acceptance because they are easy to use and less disruptive to daily life.

Over the years, ERMI has made major investments of time and money doing basic as well as clinical research projects in order to perfect the design and to demonstrate that the devices actually stretch and realign scar tissue and produce better outcomes.  

ERMI devices are prescribed for severe motion loss cases, and these are often the outliers. ERMI devices are not for everyone.

[Read more clinical Research]



A daily routine of 60 minutes of high-intensity stretching at the patient’s end range of motion is required to permanently improve motion. Many patients with severe motion loss that are treated with physical therapy alone need additional surgeries due to the simple fact that it is not feasible for a Physical Therapist to stretch a patient 60 minutes each and every day of the week.   

Home mechanical therapy devices provide patients with the opportunity to be treated on a daily basis in the comfort of their own home. In order to recreate the high-intensity stretch provided by a Physical Therapist, a home mechanical therpay device must be able to apply forces that mimic those provided by a Physical Therapist. A recent study demonstrated that home mechanical therapy devices can be categorized as being either high- or low-intensity devices, and that only the ERMI device was able to apply forces to the joint that mimic those of a Physical Therapisy*.

By recreating physical therapist in the patient’s home with an ERMI high-intensity device, patients are able to achieve lasting gaines of range of motion with less time necessary for treatment, both in terms of the amount of time per day and the number of weeks of treatment, than with low-intensity devices. A more effective stretch in less time translates into improved compliance and patient satisfaction.

A recent study compared clinical and economic outcomes for patients with knee anthrofibrosis that were treated with high-intensity mechanical therapy, low-intensity mechanical therapy, or physical therapy alone. The use of the high-intensity ERMI Knee/Ankle Flexionater®  resulted in more than $8,600 savings per patient when compared to patients treated with low-intensity mechanical therapy. The cost savings between the groups was driven by a significantly reduced risk of re-hospitalization for patients treated with the ERMI device. In addition, patients treated with physical therapy alone and without an ERMI device were almost twice as likely to require re-operation when compared to those treated with the ERMI Knee/Ankle Flexionater®.

[See more at ERMI’s Research and Evidence-Based Practice]


  • Low intensity stretch devices have been around for years and are most familiar. These are sometimes referred to as Static Progressive Stretch (SPS) braces, Low Load Prolonged Stretch, or splints.  
  • They deliver a lower amount of force than a physical therapist does.  
  • With some low intensity devices, patients are supposed to wear them around for 4-8 hours per day. Compliance is often a challenge. 
  • Many Low intensity devices commonly rely on spring-loaded mechanisms.
  • The theory is based on a creep-based principle that elastic deformation of contracted tissue will occur if a low load is applied for long durations.