A number of years ago I met an exuberant young man from South Africa named Hans de Wit. He took a course called Active Isolated Stretching: The Mattes Method (AIS), followed by observation and participation in an outpatient therapy clinic observing spinal cord, orthopedic problems, neurological diseases, postural problems and sports injuries. Mr. de Wit also observed the effects of AIS for injury prevention and improved athletic performance.

Some of the factors that illustrate the uniqueness of Active Isolated Stretching are the precise targeting of individual muscles and parts of muscles instead of large muscle groups. In contrast to a forward bend to stretch the hamstrings, AIS uses six different stretches to focus on different combinations of the medial, lateral, oblique, proximal and distal fibers. This enables the practitioner to independently evaluate and then work to maximize the flexibility of each section of the muscle. (specificity).

Although AIS stretches are supported and assisted by the practitioner, each movement is initiated and continued throughout the total stretch effort by the subject.

Contracting a muscle on one side of a joint causes the opposite side to relax (Sherrington’s Law of Reciprocal Inhibition) and that relaxation helps the muscle to stretch more thoroughly and efficiently. Moreover, having the muscles actively working helps to increase the temperature of the muscles and fascia, which enhances flexibility even farther.

Incremental assists by the practitioner provides just enough assistance to push slightly beyond what the person can do on their own making possible typical gains of 2-4 degrees with each repetition. Movements involved in AIS are gentle using less than fifty percent of the maximum potential force of the muscles being stretched. This gradual, gentle motion of 1 1 /2 seconds of actual stretch time for a repetition provides maximal safety delaying activation of the Myotatic (stretch) Reflex. The factors of gentleness (less than one pound of assisted pressure), time limit and physiological factors helps to prevent overstretching potentially causing a subsequent pain or injury.

The brief duration of a stretch has been studied by Aaron Mattes for many years. Static stretching of duration up to 60 seconds has been recommended by exercise specialists. But now it has shown that such prolonged stretching initiated the stretch reflex, decreases blood flow and oxygen within the tissues and lead to the build up of waste products, such as lactic acid and carbon dioxide that can contribute to muscle fatigue and soreness. When people stretch in this way they are working against themselves, causing a contraction of the very muscles they are trying to lengthen, which can lead to tendon irritation and even laxity, and thus predispose these structures to future injury.

In addition to working on muscles AIS helps to develop healthy joints. When the practitioner places repeated gentle tension on the fibers contained in a joint at multiple angles, the fibers of the joint itself are exercised and strengthened. Joint sensitivity and irritation diminish and often disappear with this type of stretching. Furthermore the gentle repetitive motion improves the circulation of blood and nutrients, supporting the healthy growth and repair of all the surrounding soft tissues. It also improves the circulation and drainage of lymph, helping to eliminate waste products.

Equally important is the support that AIS provides for tendons ligaments and fascia. By placing repeated gentle stress on these structures, it helps to build strength and integrity. And, when strains or tears do occur, continued AIS work helps to prevent the buildup of scar tissue – a major contributor to stiffness, inflexibility, chronic injury, and pain conditions.

Many athletes worldwide have used and are continuing to use AIS for prevention, rehabilitation and injury prevention, improving performance and lengthening athletic careers. The distance runners of Africa many of whom employ AIS are one example of great performance with few injuries. The world’s greatest sprinters have employed AIS as a part of great success. Athletes in all sports now employ AIS on a regular basis with more training and rehabilitation professionals ever being trained to assist AIS proficiency.

I highly recommend Mr. Hans de Wit as an expert practitioner of AIS. He is undoubtedly the finest AIS performer in South Africa. If there are any questions, please contact me at your earliest convenience.


Aaron L. Mattes MS. RKT. LMT


Founder and Developer of AIS