JAS devices are the ideal solution for ...

... Joint Stiffness, Range of Motion Deficit, Fixed Flexion Deformity

JAS provides a complete array of Range of Motion (ROM) therapy treatment options - Static Progressive Stretch (SPS) to address most joints.

Static Progressive Stretch is a proven treatment approach for permanently stretching shortened joint tissues, to restore ROM and function for patients following injury, surgery or disease.

JAS Knee Extension Device

All JAS devices are designed to be easy to apply, comfortable to wear, and simple to use. These factors combine to maximise patient compliance. JAS device technology enables total patient control of their ROM therapy; when patients can control the intensity of stretch, muscle guarding and pain are virtually eliminated. A variety of time efficient JAS treatment protocols have been proven effective in peer-reviewed literature and show unequalled patient compliance. Patient compliance directly equates to better results and successful rehab outcomes.

30+ peer-reviewed studies definitively show that JAS SPS therapy, providing low load stretching forces, are effective at restoring ROM in a wide variety of conditions, including knee arthrofibrosis. These studies absolutely disprove claims that effective therapy for stiff fibrotic joints can only be achieved with high torque, short duration stretch devices. JAS products provide safe and effective ROM restoration for all levels of joint stiffness.

What is Static Progressive Stretch (SPS)?

Static Progressive Stetch - or SPS - utilises the application of stress relaxation loading in a series of positional (displacement) changes. Stress relaxation applies a stretching load to a visco-elastic material (connective tissue) to reach the displacement of a desired resistance.

That displacement is held constant, so over time the connective tissue in a joint stretches and resistive loads drop (laxity). We then advance to a new point of resistance to eliminate the laxity. Once desired resistance is achieved, the new displacement is held constant until resistive load drops again. SPS is this series of progressive repositioning against resistance.

SPS mimics forces a therapist employs while manually stretching a joint. SPS is a highly efficient stretching force as shown in numerous published peer reviewed clinical studies.

What is Stress Relaxation and Low-Load Stretch?

Stress Relaxation and Low-load Stretch is defined as the reduction of forces over time in a material that is stretched and held at a constant length. This is the very same force load that forms the basis for manual physical therapy stretching techniques and the decades-old turnbuckle orthotic correction techniques.

Stress Relaxation and Low-load Stretch is the use of inelastic components – such as static line, turnbuckles, screws, and gears – to apply stress relaxation loading, the use of low intensity force to position a joint at its end range and to hold joint tissues at their maximal therapeutic length. As tissues lengthen in response to the applied stress, the splint is adjusted to position the joint tissues at their new maximal therapeutic length. This process is repeated several times during a treatment session, and sessions are performed three times daily to achieve steady increases in joint ROM. The biologic basis of using stress relaxation and low-load stretch to increase joint ROM lies in the evidence – supported biomechanical principle that low load prolonged stress applied at end range will remodel and lengthen shortened tissue.

  • JAS systems offer full-range, bi-direction Range of Motion (ROM) therapy in a lightweight, low profile design, reinforced for additional durability.
  • JAS assures precise and end-range stretch through a greater arc of motion than any other brand of stretch device.
  • Restoration of joint ROM is a critical first step in the rehabilitation process for all patients.
  • Connective tissues, because of their visco-elastic properties, will remodel to a new longer length when controlled and prolonged tensile stress is applied.
  • Tissue changes happening post-surgery and through the proceeding three months is the ideal time period for JAS therapy. The earlier you address tissue changes, the faster you will reverse it.

What factors contribute to ROM deficit?

The direct tissues that cause ROM deficit are varied and complicated but in general terms, "Arthrofibrosis is a fibrotic joint disorder characterised by excessive collagen production and adhesions that result in restricted joint motion and pain. It can occur in most joints and is referred to by a number of names, including frozen shoulder, adhesive capsulitis, joint contracture, stiff knee and stiff elbow.Sterile arthrofibrosis is typically caused by chronic or repetitive injury or surgery that leads to a dysregulated immune reaction and fibrosis in and/or around the joint to varying degrees. The fibrotic scar tissue that forms in the joint is known as extracellular matrix (ECM), and is primarily composed of collagen."


Pathological mechanisms and therapeutic outlooks for arthrofibrosisKusha et al: Nature - Bone Research (2019) 7:9

What does the patient need to do?

JAS devices allow patients total control in carrying out their ROM therapy. Because patients control the intensity of stretch, muscle guarding is virtually eliminated.

  • During each 30-minute JAS session, patients continually adjust their device to pain-free positions of end-range stretch.
  • Each position is held for 5 minutes to allow for tissue relaxation to occur before advancing to a new position of stretch.

The patient is to wear the JAS device at rest and the recommended timings are for 3 x 30-minute sessions per day.

Maximum Total End Range Time (TERT) is achieved for optimal therapeutic benefit.

The key to restoring range of motion (ROM) is not holding or moving the deficient joint in the mid-range but stretching at the very end of its range where the tissues are actually contracted. Holding at the end range for 30 minutes 3 x per day results in the plastic deformation of the contracted tissue back to its native state, with subsequent permanent restoration of mobility at the end range.The total time that a joint is held at its end range is termed the TERT or Total End Range Time.

Total End Range Time (TERT)

What is pain-free stretch?

Step One

Rotate therapy knob until a gentle, pain-free stretch is felt.
Attempt to achieve Level 2-3 on stretch intensity scale of 1-10 (1 = no stretch | 10 = painful stretch).

Step Two

Hold stretch position for 5 minutes. Before turning the knob, re-assess stretch level:

  • If stretch has decreased, rotate knob until you feel a level 2-3 stretch again.
  • If stretch intensity has not changed, leave in same position.
  • If stretch has increased, rotate knob in opposite direction until a level 2-3 stretch is felt.
Step Three

Hold stretch for another 5 minutes.

Repeat process for 6 stretches to complete a 30-minute therapy session.

How to apply and use:

1. Apply device

  • Sit in a comfortable position.
  • Open all hook and loop fabric straps on the device.
  • Adjust arc of the device to match the starting position of your comfortable range of motion.
  • Place your limb in the device with the affected joint centred over the proper marker on the device.
  • Secure all hook and loop fabric straps to ensure snug fit.

2. Get into a comfortable position

  • See guidelines to the right for proper position before performing your JAS therapy.

3. Perform your JAS Therapy as above.

Click here to learn more about the tendons and ligaments in the knee joint

JAS devices are available for all of the following joints:

JAS GL Knee Extension

JAS GL Knee Extension, offers:

A no-compromise approach to Range of Motion (ROM) therapy - 48 degree flexion, 36 degree hyperextension - in a lightweight, easy-fit device reinforced for additional durability.

JAS GL Shoulder

JAS GL Shoulder, offers:

Full range, multi-plane Range of Motion (ROM) therapy - 100 degree external rotation, 90 degree internal rotation and 90 degree abduction - in a lightweight, low-profile device reinforced for additional durability.

JAS GL Wrist

JAS GL Wrist, offers:

Full range, bi-directional Range of Motion (ROM) therapy - 90 degree flexion, 90 degree extension - in a lightweight, low-profile device reinforced for additional durability.

JAS GL Knee Flexion

JAS GL Knee Flexion, offers:

A no-compromise approach to Range of Motion (ROM) therapy - 50 degree flexion, 148 degree flexion - in a lightweight, easy-fit device reinforced for additional durability.

JAS GL Finger

JAS GL Finger, offers:

Full range, bi-directional PIP Range of Motion (ROM) therapy - 100 degree flexion, 10 degree hyperextension - in a lightweight, low-profile device reinforced for additional durability.

JAS GL Ankle

JAS GL Ankle, offers:

Full range, bi-directional Range of Motion (ROM) therapy - 40 degree dorsiflexion and 52 degree plantar flexion - in a lightweight, low-profile device reinforced for additional durability.

JAS GL Elbow

JAS GL Elbow, offers:

Full range, bi-directional Range of Motion (ROM) therapy - 167 degree flexion, 15 degree hyperextension - in a lightweight, low profile device reinforced for additional durability.

JAS GL Pro/Sup, offers:

Full range, bi-directional Range of Motion (ROM) therapy - 110 degree pronation, 130 degree supination - in a lightweight, low-profile device reinforced for additional durability.


JAS GL Toe, offers:

Full range, bi-directional ROM therapy for the great toe, from 90 degree dorsi-flexion to 45 degree plantar-flexion in a lightweight, simple-to-use device reinforced for additional durability.

JAS Paediatric range of devices:

Features and benefits of JAS


  • Anatomically correct arc of motion
  • Lightweight, easy to apply and simple to use
  • Fulcrum positioned away from the joint
  • 30-minute treatment sessions
  • Patient-controlled, infinitely adjustable ROM
  • Stimulates manual stretch
  • Bi-directional ROM provided in all devices except the adult knee
  • Precision fit


  • Delivers optimal stretch loads through entire ROM
  • Promotes excellent patient compliance
  • Eliminates joint compression and pain
  • Dramatically reduced treatment time ensures high patient compliance
  • Assures precise and pain-free end-range stretch eliminates muscle guarding
  • Provides clinic-quality stretch in the home setting
  • Saves cost: full-range stress relaxation therapy in one device
  • Optimal comfort and accurate stretch eliminates risk of skin breakdown

Do you need support?

You are very welcome to contact a medi Customer Service representative for advice on products, best practices or questions.

Clinical Application - JAS Knee

JAS Knee Flexion Brace
  • TKR
  • Ligament Repair - ACL, PCL
  • Femur / Tibia Fractures
  • Arthrofibrosis
  • Manipulation
  • Quad/Patella Tendon
  • Burns
  • Neurologic

Clinical Application - JAS Elbow

JAS Elbow Device
  • Distal Humerus Fractures
  • Radial Head Fractures
  • Olecranon Fractures
  • Post-Trauma Stiffness
  • Elbow Dislocation
  • Tendon/Ligament Repairs
  • Post Surgical Release - Immediate Use
  • Neurologic

Measurement and Order Forms:

Each device is assembled to order and you will need to take the measurements, depending on which column is relevant to you.

Click here to download the Upper and Lower Extremity Device Measuring and Order Form


When is it safe to begin JAS ROM Therapy?

As soon as a patient is cleared for passive stretching post injury or surgery, it is safe to add a home program of SPS therapy.

When is the ideal time to begin JAS ROM Therapy?

Research shows that ideal time to apply low load prolonged stretch is during the adaptive phase of wound healing, or within 90 days post trauma. Collagen fibres are most responsive to remodelling forces such as SPS in this time period. With that in mind JAS ROM therapy should be started as soon as a delay in achieving ROM gains is recognised.

How does JAS work?

Static Progressive Stretch safely restores joint motion using the physiotherapy principle of low-load graduated stretch.

By turning the ROM knob, the joint is moved to a pain-free stretched position and held there for several minutes, to allow for the surrounding tissues to relax and lengthen. This process is repeated several times to complete SPS treatment session.

When is the best time to start the JAS therapy?

Once your doctor has cleared you to begin passive stretching, and after 2-4 weeks of physiotherapy treatment, if you are not making expected gains in joint ROM.

When should I use my JAS device?

JAS 30-minute sessions can be done any time of day, when and where it is convenient for the patient. It is important that the patient is inactive and relaxed, such as watching TV, at the computer or lying in bed.

I am using JAS and it hurts after 10 minutes. What should I do?

Simply dial down the pressure and continue with pain-free stretch.

I am using JAS but haven't noticed an improvement. Is it working?

Dial up the pressure slightly during sessions, to ensure you are getting adequate level of stretch.