The concept of reactive muscles was introduced by David Walther in his book “Applied Kinesiology”. When two muscles are in relationships such as synergistic or antagonistic, one muscle has the ability to compensate for the other. Although the muscles may manually test strong or facilitated by themselves, in relationship one muscle may inhibit the other. This is called a “reactive pair”. Understanding this dynamic is crucial in working with dysfunctional movement patterns. A good example would be a client presenting with lower back pain. First test the transverse abdominis and it tests strong. From this you might assume that this muscle is working just fine and is not contributing to the problem. Then test the lumbar erectors. Let’s say they test strong. Then retest the transverse abdominis. Now you find that it tests weak. This reactive relationship clearly is contributing to the lower back pain. Using the NeuroKinetic Therapy protocol, the lumbar erectors are released so that the transverse abdominis becomes facilitated. This can be the underlying reason for unresolved lower back pain. This is a classic example of a reactive antagonistic relationship.
When we use our muscles in concert with each other there is a natural flow of effort transmitted from one muscle to the other. A good example of this is picking up a glass of water and drinking it. First you need to grasp the glass, requiring intrinsic and extrinsic muscles of the hand. Then the wrist and elbow must bend, requiring muscles of the forearm and humerus. Then the shoulder must flex and finally the mouth must open. This is a complex action which normally requires no conscious thought. In other words, it has become a motor program. However, if there has been an injury or a long-standing postural distortion, this normally effortless action becomes compromised. We can call this a synergistic reactive relationship. Any muscle in this chain of action can inhibit another. A tight jaw could cause a weak grip. Check this out by first testing the grip. Is the client clenching his/her jaw? If so, release the involved jaw muscles before retesting the grip. You will find that the grip now tests strong. I have found the scalenes in this kind of reactive relationship to 13 different muscles further down this chain. Is it any wonder that the client was diagnosed with thoracic outlet syndrome?
Knowing how to work with reactive muscle relationships is an essential element in rehabilitative therapy. This powerful tool can help you unlock the secrets of dysfunctional movement and coordination patterns.