When a machine moves, the stress on the moving components will deteriorate or wear out the machinery. If the alignment of specific segments or moving parts is not ideal, the machine will eventually break down. Unlike machinery, stress on the moving segments of the human body is necessary and gradual stress can improve the resistance of the tissues involved, two of the advantageous characteristics of the human body. There are upper and lower limits that determine whether or not it will be beneficial to tissue health. Any loss in precise movement can initiate a process that can induce changes that can cause micro trauma to macro trauma to the tissues involved. I will try to give you examples of common movement impairment syndromes that will create faulty mechanical wear and tear that will eventually lead to pain or dysfunction.
Weakness from overstretching
Muscles can weaken when held in a long position, especially when stretching occurs during periods of prolonged rest. For example, the development of elongated dorsiflexor muscles and shortened plantar flexors in the patient confined to supine bed rest with the sheets exerting a downward pull on the feet, causing additional force on plantar flexion, thus elongating the dorsiflexor muscles. Another example is the prolonged stretch of the posterior gluteus medius that occurs while sleeping on your side. A woman with a wide pelvis with her upper leg adducted, flexed, and medially rotated will result in weak hip abduction, extension, and lateral rotation. The resulting lengthening of the muscle can cause postural hip adduction or an apparent discrepancy in leg length in a standing position.
Sleeping in a lateral decubitus position with the lower part of the shoulder pushed forward pushes the scapula into abduction and leans forward. This position can stretch the lower trapezius and possibly the rhomboids. The upper shoulder may also be susceptible to pulling the scapula into a forward abducted position, especially if the chest is large. This sleeping position can cause the humeral head on the glenoid to migrate into a forward position.
Characteristics of muscles with overstretched weakness include:
1. Muscle-controlled postural alignment indicates that the muscle is longer than ideal.
2. Testing weak muscle throughout its range of motion and not just in its shortened position.
Overstretching weakness can also be caused by straining when trying to lift a heavy object. Remember, strain is a minor form of tear in which the muscle filaments have been stretched or stressed beyond their physiological limit, resulting in the disruption of the Z lines that actin filaments adhere to. These alterations alter the alignment of the myofilaments, which interferes with the tension-generating capacity of the contractile elements. Muscle weakness and, in many cases, pain occurs when the muscle is palpated or when resistance is applied during muscle contractions. For example, if the upper trapezius is tight, the weight of the shoulder girdle itself may be too much for the muscle. The pull of the shoulder on the muscle causes it to lengthen and the muscle cannot heal. A strained muscle can be under constant tension even when it appears to be at its normal resting length. Generally, a tight muscle cannot hold against gravity when placed at the end of its range. Also, the muscle cannot maintain its tension at any point in the range when resistance is applied.
When a muscle lengthens and weakens, then its contribution or stress-generating capabilities will change and another muscle will have to take over, creating a compensatory movement pattern. This will eventually become the normal pattern which will later cause health problems down the road. Therefore, stretching may not always be optimal for relieving pain or muscle spasm. Stretching and applying excessive force to the muscle is contraindicated if it is tight. It is the length of the muscle and the presence of pain that acts as a guide to determine whether the muscle is simply weak from atrophy or from weak tension.
Traditionally, the emphasis has been on stretching the muscles that have been shortened, but the same emphasis has not been placed on correcting the muscles that have been lengthened. Elongated muscles do not automatically shorten when the antagonist is stretched. A client demonstrating lower withers may have an exercise program that stretches the hamstrings, however this does not simultaneously shorten elongated muscles, such as the lumbar extensors of the back. Care must be taken to shorten the elongated muscle and at the same time stretch the shortened muscle. This is especially important when the elongated muscle controls the joint that becomes the site of compensatory movement as a result of the limited movement caused by the shortened muscles. For example, during forward flexion, excessive lumbar flexion can occur as a compensatory movement due to shortening of the hamstrings. The best intervention would be to stretch the tight hamstrings, but also to shorten the extensor muscles of the back.
Altered hiring patterns
A person with shoulder pain has excessive shoulder elevation during shoulder flexion to 90 degrees compared to a person without shoulder pain. The elevation is present even after the patient no longer experiences pain. Runners who tend to keep their weight closer to the back than the front of the foot show that they use the hip flexion strategy, which also involves overuse of the tibialis anterior muscle, leading to leg cramps. pimples. On the contrary, it can be seen that runners who keep their weight line forward use the plantar flexor muscles of the ankle more.
The upper trapezius muscle, which is the upper component of the torque that controls the upward rotation of the scapula, may be more dominant than the lower trapezius. Muscle tests may show weakness of the lower trapezius or serratus anterior. One might notice an excessive elevation of the shoulder when abducting the arm. Strengthening muscle may not necessarily change the recruitment pattern. Instructing the client in the correct execution of the shoulder movement using a mirror is as important as the strengthening exercises you can prescribe.
An individual with an exaggerated rearward posture who stands in extension of the hip joint has a diminished contour of the gluteal muscles, suggesting a weakness in these muscles. The hamstrings will generally absorb the slack at the hip extension. The hamstrings are extremely susceptible to an overuse syndrome when dominant due to improper involvement of the abdomen, gluteus maximus or even rectus femoris, as well as the lateral rotators of the hip.
The TFL (Tensor Fascia Lata) and Rectus Femoris muscles are more dominant than the hip flexion of the iliopsoas muscle. In this situation, the client will show excessive medial hip rotation. The person generally has a leaning back posture.
The TFL, gluteus medius anterior, and gluteus minimus muscles are more dominant than the gluteus posterior muscle in the hip abduction action. When abducting, the client will substitute for medial rotation and hip flexion.
The extensor digitorum longus is more dominant than the tibialis anterior for the action of ankle dorsiflexion. The client will extend the toes as the initial dorsiflexion movement instead of the ankle movement.
The hamstring muscles are most dominant for the knee extension action. When walking or running, once the foot is fixed on the ground, the extension action of the hip from the hamstrings contributes to the extension of the knee. Hip extension to aid in knee extension is commonly used by the person with quadriceps muscle weakness. To reinforce the knee extension action, the person flexes the trunk slightly to use gravity to further contribute to the knee extension movement. A similar pattern is seen in the runner using the hamstrings to control knee extension. It will bring the knee back toward the body, rather than bringing the body down to the knee, as when climbing stairs.
When asked to do finger extension, many people will demonstrate a small degree of wrist flexion. This type of compensatory movement pattern occurs most often in people who do a lot of repetitive wrist bends, such as typing. As a result of this position of the flexion movement of the wrist, the position of the flexed joint and the anterior position of the flexor tendons reduce the carpal tunnel space, which can result in carpal tunnel syndrome.
In summary, mechanical stress on tissues that arises from movement impairment syndromes can cause a wide variety of injuries. The various injuries involved can be degenerative changes in cartilage and joints, ligament strains, joint inflammation, myofascial strains, myofascial tears, tendinitis, bursitis, neuropathic pain due to entrapment and compression and adhesions are some examples. The better the muscle testing and identification of these compensatory movement patterns, the better you can prevent your clients from injuring themselves.