The concept of balanced movement is NOT just for Yoga. It appears throughout the body, as a way for functional muscles to prevent injury where the joint fits its function and follows the form of the muscles called into use for posture, exercise, and daily movement. Consider again the shape of the hip and knee...so that we reinforce the action.
Myofascial Trigger Points (MTPs) are associated with reduced efficiency of reciprocal inhibition in the opposing muscles. Muscles exhibiting MTPs may contribute to delayed and incomplete muscle relaxation following exercise, confusion of excellent movement control, and unbalanced muscle activation. Eliminating latent MTPs and prevention of active MTPs from latent motion inhibition will improve motor functions and reduce pain in all situations. I will also prevent further challenges for your clients.
Cycle of Degeneration
When muscles pain develops, because muscles are attached and closely influence joint function in the human body, the impact of dysfunction and pain are interconnected. Myofascial Pain (MFP) caused by motion at one joint is related to actions at adjacent joints, abnormal movements, or compensation. From the lower to upper attachments - and in closer into the core, the more challenged muscles are the more compensation created from, the lower limbs and lower trunk into the upper arms and upper chest the harder the body has to work.
When MFP persists for a reasonable time without treatment, adjacent structures may also evolve secondary problems called satellites TrPs. MFP can impede normal joint motion, cause joint and muscle dysfunction, and lead to joint degeneration, as well a chronic pain.
The Biomechanical Yin/Yang of Muscles in Movement
Muscles fall into three primary groups, and these depend on what they are doing at any given moment. When looking at the bending of the knee: the quadriceps are the agonists and create the movement, during standing while the hamstrings are the antagonists and allow the action to lengthening and support. Vise versa, the Hamstrings become the agonist muscles when the knee bends - or when you sit down, the Quads allow the movement by balancing the contraction of the hamstrings. The adductors are the synergists (and go along for the ride), as do the abductors like the Glutes and Hip Flexors...except they all exert influence throughout the movement to produce the bending and extension of the knee.
Here's the point, for the knee to flex and extend without pain a comfortable range of motion - these muscles have to be balanced. If the hamstrings are too tight, there is an excessive pull at the hips and knee - which doesn't allow contraction (in some cases without pain). If the quads are too tight, then the pull into the hip bones may be too much for the hamstrings to balance the adductors and quadriceps without extra effort. Have you ever wondered by you suddenly feel that your knee 'gives' way, or that your legs are super weak after extended sitting while playing video games? This is the effect of the level of tension being too tight to allow the muscles to move in the way you expected.
The Physiology of Reciprocal Inhibition - and the Balance
The corresponding physiological, biomechanical processes that contribute to pain include prolonged dynamic exercise, and sustained isometric contractions induce muscle fatigue, as manifested by task failure and a reduction in the maximum voluntary contraction force [1,2]. Lower muscle strength and accelerated fatigue development are commonly reported in patients with chronic musculoskeletal pain [3,4], where both latent and active myofascial trigger points (MTPs) contribute significantly to the generation of pain and motor dysfunction [5–7].
Muscle fatigue is prevalent in acute and chronic musculoskeletal pain conditions where Myofascial trigger points (MTPs) are involved and have evolved due to postural and joint laxity. The study aimed to investigate the association of latent MTPs and if muscle fatigue was directly related to the presence of MTPs that are latent - not showing pain referrals. Muscle fatigue may arise not only from peripheral changes at the level of the muscle but also from the central nervous system . Central fatigue may be affected by psychological factors, such as perceived effort or physiological factors, such as inhibition of pathways that prevent efficient activation of motor neuron pools . The fatigue of the shoulder muscles can come from multiple areas of the joint
Of all the shoulder pain trigger points that I have treated, the infraspinatus trigger points are the most effective because they resolve immediate pain. Many patients think that it’s magic when I recreate the pain in the front of their shoulder by pressing on top of the shoulder blade. It’s not magic, of course, it’s just good myofascial pain techniques. If you are not familiar with the “magical” infraspinatus and the symptoms that create pain in opposite areas of the shoulder joint.
The Infraspinatus Muscle
Anatomy & Biomechanics: Let’s begin with a few anatomical and biomechanical details of this muscle. The infraspinatus muscle is found on the back of the shoulder blade and extends laterally to attach to the posterior aspect of the head of the humerus (upper arm) bone. This muscle has two important jobs:
Lateral Rotation of the Arm: Contraction of this muscle rotates the arm to the outside at the shoulder. The simple act of raising your hand to wave hello to someone is a good example of the infraspinatus muscle at work (among others).
Stabilize the Shoulder Joint: As one of the rotator cuff muscles, the infraspinatus contracts to stabilize the shoulder joint and keep the head of the humerus from slipping out of its socket during shoulder movement.
Syngeristic Muscles: The infraspinatus gets some help with its jobs from some of the other muscles in the shoulder girdle. The teres minor and deltoid (posterior head) muscles assist with lateral rotation of the arm, and the other rotator cuff muscles team up to assist with stabilizing the glenohumeral joint during various arm movements. The major antagonists to the infraspinatus are the subscapularis and pectoralis major muscles, both of which act to medially rotate the arm.
The Infraspinatus Trigger Points & Referred Pain
This muscle has three trigger points, arranged in a triangular pattern within the belly of the muscle. Typically, the lower trigger point is the most common and most active in shoulder pain complaints. Referred pain from these trigger points is experienced deep in the front of the shoulder joint and along the upper arm. The pain may also spill down into the forearm and hand regions in severe cases.
Associated Trigger Points: Prolonged referred pain from these trigger points can activate the deltoid trigger points on the front of the shoulder. Referred pain in the forearm region may also activate wrist trigger points over time, because of the relationship to the subscapularis (discussed in our other blog post).
What Causes Infraspinatus Trigger Points?
As detailed in the “Muscles and Stretching: Trigger Points” article, trigger points are activated (or reactivated) primarily by some form of muscular overload. In the infraspinatus muscle, overload can occur with any activity or event that requires a person to reach backwards with the arm or that keeps the arm raised to the front for long periods. The other is the same motion at lower intensity during a long period of time. Examples include:
throwing a baseball or football
forehand stroke in tennis
walking a large dog that pulls on the leash
long hours working at a computer keyboard with no elbow support
bracing for a fall or slip by reaching behind the body
long drives with the hands positioned on the top of the steering wheel
beginning a new resistance training (weight lifting) routine will often overload any of the rotator cuff muscles
Infraspinatus Symptoms & Disorders
Patients/clients with active trigger points in this muscle will present with the following symptoms:
Front of Shoulder Pain: This is the hallmark symptom for the infraspinatus trigger points. The pain feels deep within the shoulder joint, causes many clients concern for “strains or sprains” in the shoulder joint itself.
Inability to Reach Behind the Back: Clients will report that they are unable to reach behind their back to put on a shirt, or get the purse out of a back seat These movements require significant internal rotation of the shoulder, which stretches the tense muscle and aggravates the trigger points.
Inability to Raise Arm Up To Head: Clients will report that they are unable to raise their arm above shoulder height without extreme pain, this prohibits them from brush their teeth, or even to bring food to their mouth without pain.
Inability to Push With Arms: Clients will complain of shoulder pain when using their arms to push up when trying to stand out of a chair, or when rising up out of bed in the morning they can’t support their weight. Weight lifting exercises like the bench press, inclined bench press, and military press are nearly impossible with active infraspinatus trigger points.
Shoulder Pain at Night: Infraspinatus trigger points can be a double-edged sword when trying to sleep on the side. If the client lays on the affected shoulder, the weight of the upper body can compress the trigger points and produce referred pain. If the client lays on the unaffected shoulder, the upper arm may hangs down in front of the body and places the affected infraspinatus in a prolonged stretched state, aggravating the trigger points again. In severe cases, the client may be forced to sleep in a sitting position to prevent the pain from disturbing their sleep.
Bicepital Tendonitis: The role that infraspinatus trigger points play in many cases of bicepital tendonitis deserves special mention. This is characterized by tenderness and pain in the biceps brachii, or the front region of the upper arm, near the shoulder joint. It is prevalent in baseball pitchers, gymnasts, volleyball players, football quarterbacks, and tennis players.
Treatment of the Infraspinatus Trigger Points
It is important for the therapist to check for and address any trigger point activity in the supraspinatus and deltoid muscles after treatment of the infraspinatus trigger points. Deltoid trigger points are likely to form in response to the referred pain from infraspinatus trigger points, and supraspinatus trigger points are nearly always conspicuous in rotator cuff issues.
Myofascial pain syndrome is an important health problem. It affects a majority of the general population, impairs mobility, causes pain, and reduces the overall sense of well-being. Underlying this syndrome is the existence of painful taut bands of muscle that contain discrete, hypersensitive locations called myofascial trigger points. In spite of the significant impact on public health, a clear mechanistic understanding of the disorder does not exist. This is likely due to the complex nature of the disorder which involves the integration of cellular signaling, excitation-contraction coupling, neuromuscular inputs, local circulation, and energy metabolism. The difficulties are further exacerbated by the lack of an animal model for myofascial pain to test mechanistic hypothesis. In this review, current theories for myofascial pain are presented and their relative strengths and weaknesses are discussed. Based on new findings linking mechanoactivation of reactive oxygen species signaling to destabilized calcium signaling, we put forth a novel mechanistic hypothesis for the initiation and maintenance of myofascial trigger points. It is hoped that this lays a new foundation for understanding myofascial pain syndrome and how current therapies work, and gives key insights that will lead to the improvement of therapies for its treatment.
At the cellular level, limitations in energy supply, including the energy available from phosphocreatine hydrolysis, anaerobic glycolysis and oxidative metabolism, as well as the intramuscular build up of metabolic by-products, such as hydrogen ions, become the critical factors of the fatigue in the muscles of the body. MTPs have been reported to showing an increased concentration of algesic substances, including hydrogen ions  and muscle ischemia  - lack of oxygen associated with sympathetic hyperactivity . Apart from the sensory hypersensitivity at MTPs, latent MTPs are related to abnormal muscle activation pattern  and increased resting motoneuron excitability . These mechanisms may predispose taut muscle fibers harboring MTPs to an early onset of muscle fatigue in sustained isometric contractions.
Looking at predisposing and perpetuating factors from chronic overuse or stress injury on muscles helps eliminate the source of the pain. If possible. Pharmacologic treatment of patients with chronic musculoskeletal pain includes analgesics and medications to induce sleep and relax muscles. Antidepressants, neuroleptics, or nonsteroidal anti-inflammatory drugs are often prescribed for patients. Furthermore, the manual treatments above can be used for immediate pain relief.
Nonpharmacologic treatment modalities include acupuncture, osteopathic manual medicine techniques, massage, acupressure, ultrasonography, application of heat or ice, diathermy, transcutaneous electrical nerve stimulation, ethyl chloride Spray and Stretch technique, dry needling, and trigger-point injections with local anesthetic, saline, or steroid. The long-term clinical efficacy of various therapies is not clear, because data that incorporate pre- and post-treatment assessments with control groups are not available.