Forty years ago, an athlete named Aaron Mattes was frustrated with continuous injuries and what he saw as ineffective rehabilitative methods. For a hamstring stretch, he had been taught to rest his foot on a bench and reach for his toes. That methodology left him sorer and his hamstrings screaming. Sound familiar? Spurred on by the lack of solutions offered by the medical community, Mattes took matters into his own hands. Laying down on his back he experimented with a rope to assist him in a hamstring stretch that did not put his muscles in an eccentric contraction. He discovered that movements against gravity held only for two seconds enhanced elasticity in the tissues without them fighting back. And so Active Isolated Stretching (AIS): The Mattes Method was conceived.
What it is
Active Isolated Stretching is a myofascial release technique that reaches all muscle groups in the body. Fifty percent of these muscles are difficult to palpate, such as the deep hip rotators, psoas, iliacus, and the subscapularis, which proves challenging for the usual methodology such as massage. By studying the origin, insertion, and action of every muscle, Mattes developed over 170 stretches predicated on the alignment of myofascial planes and muscle fibers.  Using this technique, we can target areas, which once seemed impossible to reach, bringing in more fresh blood and oxygen. One of the most notable traits of AIS is that it works with the body’s natural reflexes, creating fast results. With rhythmic breathing and six to eight ounces of pressure, the muscle is taken beyond its current range of motion. In a single set of ten, easy, two-second repetitions of AIS, the muscle is often able to increase anywhere from five to more than twenty degrees. The dramatic increases with Active Isolated Stretching are possible because the antagonist muscle is completely relaxed while the agonist is in a state of contraction.
Why Stretching Is Important
With the repetitive movement of running, the joints get used to a restricted range of motion, and when pushed beyond that range, injuries can result. We tend to use the same muscles in the same way, therefore overusing some, and under utilizing others. Misconceptions based on the outdated method of holding a stretch for 15 seconds to two minutes have caused some athletes to injure themselves, possibly decreasing their running times. As a result, they may avoid stretching all together. With further education in proper dynamic stretching, we have the chance to enhance all aspects of running. An increase in flexibility and elasticity has an impact on agility, speed, and endurance. With proper stretching, you can run faster, slow the process of fatigue, and have a longer lasting running career. The more elastic our muscles are, the less likely they are to tear. Gentle stretching clears the body of metabolic wastes and toxins, and prevents lactic acid buildup associated with delayed onset muscle soreness. Muscles will rejuvenate more quickly with proper stretching and strengthening, because both flexibility and strength keep the joints stabilized. In illustration, San Diego Padre Mark Loretta, after suffering countless injuries worked with Aaron Mattes and added two, ten-minute AIS sessions to his daily routine. The result, according to Loretta was increased flexibility and agility, and decreased rates of injury. 
Respecting the Myotatic Stretch Reflex
Active Isolated Stretching is based on respecting the myotatic stretch reflex. This reflex is the body’s defense mechanism to protect itself from being injured, by being over stretched or stretched too quickly. The myotatic reflex, stored in the muscle spindles, is triggered after two seconds causing the antagonist muscle to contract. There are three components to the response. Time– duration of muscle lengthening; Force – how hard the muscle is being assisted; and Speed – how quickly the muscle is put into position. If any of these elements are compromised then injury can, or is likely, to occur.
When the muscle spindles detect lengthening, the Golgi Tendon Organ sends an impulse to the Central Nervous System (CNS) to convey “danger!” The CNS sends a message back saying, “Shut it down.” This takes one and a half to two seconds. If you ignore the message, the myotatic reflex will cause the muscle to fight back. Setting off the myotatic reflex can lead to muscle soreness, fatigue, and tissue tearing. Rather than trying to override the myotatic stretch reflex, AIS employs repetitions of two-second stretches that honor how the body really works.
Muscles respond more quickly to gentle coaxing to increase their flexibility. The amount of pressure applied to the muscle is important because pushing the muscle too hard will cause it to contract instead of stretch. According to Mattes’ principles, only six to eight ounces of pressure need be applied in order to reach optimal lengthening. With gentle assistance, either individually or with a therapist, it is possible to increase flexibility by two to three degrees with each repetition.
Contrary to popular belief, bouncing or jerking movements should be avoided. Movements that are too sudden can set off the stretch reflex, contracting the antagonist muscle. Please keep in mind there needs to be a relaxation phase between each repetition, allowing the muscle to refill with fresh blood and oxygen. Disengagement between repetitions allows for fluid exchange and neurological resetting of muscle length.
Timing is assisted with rhythmic breathing. Exhaling into each stretch releases tension and expands the muscles. Moreover, a stretch lasting longer than two seconds becomes ischemic, squeezing the blood out of the muscle and cutting off the oxygen supply through muscle contraction. Anything held less than one and half to two seconds does not allow for maximum blood and oxygen flow.
Common injuries experienced by runners are ankle sprains, Achilles tendonitis, plantar fasciitis, bunions, Tensor Fascia Latae – Iliotibial band (TFL-ITB) tendinitis, knee problems, shin splints, arthritis – the list goes on. Regular practice of Active Isolated Stretching has been shown to prevent many of these injuries and aid in healing without surgery. Imbalance and lack of flexibility can result in injury. For example, running only on the balls of the feet leads to loss of full range of motion in the calves, therefore making the runner vulnerable to Achilles tendonitis, plantar fasciitis, and heel spurs. Quadriceps that are too tight compress the meniscus and contribute to condromalacia (wearing away the back of the knee cap). Mattes has designed stretches for the muscles crossing each joint. The muscles crossing two joints such as the rectus femoris, biceps femoris, and the TFL-ITB need special attention, they are the most commonly torn or strained. There are separate stretches for the distal, proximal, lateral, and medial fibers. Shin splints, plantar fasciitis, high arches, and Achilles tendon injuries are usually caused by tight calf muscles and weak ankles. These injuries can be prevented with proper stretching and strengthening. With AIS, the muscle opposite of the one being stretched is being strengthened at the same time, which creates space in the joints as well as stability. Injuries like stress fractures occur because the feet are weak. By focusing on the individual muscles in the foot, these injuries can be prevented. In order to reach the 20 muscles in the foot there are stretches for every joint of every toe, as well as the various angles of the soleus, achilles, gastrocnemius, and muscles surrounding the ankle. A runner suffering from plantar fasciitis was placed in a boot for 4 months with less than optimal results. After two sessions of Active Isolated Stretching and Strengthening treatment, he walked out “boot free.”