Connective tissues surrounding joints (such as joint capsule, tendons, ligaments, skin, and adhesions) are viscoelastic, and often shorten in response to trauma, surgery, disease, and prolonged immobilization, resulting in loss of joint ROM. Stress Relaxation and Low-load Stretch are fundamental and well proven treatment techniques used to permanently lengthen shortened connective tissues.
What is Static Progressive Stretch?
Static Progressive Stretch - or SPS - utilizes the application of Stress Relaxation loading in a series of positional (displacement) changes. Stress Relaxation applies a stretching load to a viscoelastic 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. “Static Progressive Stretch” – 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 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.
Devices such as the JAS brand allow stress relaxation and low-load stretch to be delivered in the home setting outside of the therapy clinic. They are most often used as an adjunct to therapy when adequate ROM gains are not being achieved with a standard course of therapy and home exercise.
Multiple research studies have shown that the earlier adjunctive stress relaxation and low-load stretch therapy is initiated, the greater are the total gains in joint ROM.
Published research proves that stress relaxation and low-load stretch achieves permanent soft tissue elongation faster than creep/dynamic splinting. The recommended JAS protocol of three 30-minute sessions per day has been clinically proven to achieve steady and permanent gains in joint ROM.
See the Research section for a listing of clinical studies.