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How to Improve Posture

I get visits in the clinic from people who don't have pain, but simply want to know how to improve posture either in themselves or in their children. Do you feel like you struggle to stay upright? Are your shoulders always pulling you forward? Do you struggle to touch the floor because you have tight hamstrings? Do you suffer from mid-back fatigue and burning? Most of us are involved in occupations that involve work in front of us - sitting at computers with our hips and knees bent, head and shoulders forward, elbows bent and palms down. Alternatively we stand for long periods with our hips forward, slouched often, working on something in front of us. We tend to overuse some muscles and underuse others and this is what causes postural problems. Maintaining proper posture can be a struggle between the overused muscles and the underused phasic muscles.

Why are Some Muscles Tight and Others Weak?
What are Upper Crossed and Lower Crossed Syndromes?
How Can We Use this to Improve Stretching?

how to improve posture

Why are Some Muscles Tight and Others Weak?

One hypothesis is that poor motor control causes poor movement patterning and imbalance between phasic muscles and tonic muscles. Phasic muscles are those that have a tendency to become weak and inhibited under conditions such as those listed above. These phasic muscles typically work eccentrically against gravity.  We can improve posture by increasing activity in these phasic muscles.

This theory of phasic versus tonic muscles was first introduced to the medical community in 1979. Dr Janda, a Czech physician pursued his interest in physiotherapy after he finished medical school and was one of the first medical doctors to work in the field of physical medicine and rehabilitation. His theories on muscle imbalance and pain syndromes are used worldwide by physical therapists and physiatrists. He identified muscles that are prone to becoming tight, and short, and other muscles that are prone to becoming weak or inhibited by pain, stress, poor positioning, etc.

His tonic muscles are those that are involved in repetitive activities and are dominant in a child shortly after birth. The phasic muscles develop as the child works against gravity and become stronger as the child's nervous system matures.  In people that suffer a stroke or cerebral palsy the flexor/tonic muscles dominate movement suggesting that muscle imbalances may in part be due to central nervous system influence - not just changes in the structure of the muscle and shortening of connective tissues.

Tight Tonic Muscles

Weak Inhibited Phasic Muscles

Upper Trapezius Rhomboids
Pectoral Muscles Hyoids
Sternocleidomastoid Serratus Anterior
Levator Scapulae Deep Neck Flexors
Suboccipital Muscles Infraspinatus
Subscapularis Teres Minor
Scalene Supraspinatus
Latissimus Dorsi  

Tight Tonic Muscles

Weak Inhibited Phasic Muscles

Rectus Femoris Rectus Abdominis
Hip Flexors Vastus Medialis
Hamstrings Vastus Lateralis
Erector Spinae Glutes
Hip Adductors Transversus Abdominis
Tensor Fascia Lata  
Piriformis  
Quadratus Lumborum  

Stable posture requires a balance in activity of the phasic and tonic muscles otherwise pain and instability results.
Muscle imbalances result in a predictable manner. Janda classified these imbalances as "upper crossed syndrome" and "lower crossed syndrome".

What are Upper Crossed and Lower Crossed Syndromes

The upper crossed syndrome involves facilitation of  levator scapulae, the upper fibres of trapezius, sternocleidomastoid, and pectoral muscles, and  inhibition of deep neck flexors, serratus anterior, and lower fibres of trapezius. The lower crossed syndrome involves facilitation of rectus femoris, the thoracic and lumbar extensors,  and the iliopsoas muscle, and inhibition of abdominal muscles and the glutes. These muscles prone to tightness have a lower threshold for activation so can become hypertonic.

These tight tonic muscles pull your head and shoulders forward forcing muscles that control your shoulder blades to weaken resulting in shoulder impingement issues. Tightness in the suboccipital muscles cause headaches. Weakness in the deep neck flexors cause neck instabilities. You can see how a series of muscle imbalances can alter your movement patterns create poor posture and cause pain and injury.

Because of the reciprocal inhibition of muscles, the tight muscle inhibits its antagonist. For example, the pectoral muscles work with the rhomboids and middle traps to control scapular positioning on the thorax. If the pectoral muscles are tight, their muscle spindles fire excessively which causes a reflex inhibition to the rhomboids and middle traps. This constant inhibition results in weakening over the long term. As the pectoral muscles become tight, the scapulae assume a new forward position. this is the rounded shoulder posture we see in many people that work at desks all day.

Tight muscles limit mobility causing pain and weak muscles fail to support joints leading to premature degeneration. So while it is important to stretch what is tight, it is also important to strengthen what is weak. Good posture and ease of movement is achieved by stretching tight tonic muscles allowing their antagonists to respond to strengthening exercises.

How Can We Use this knowledge to Improve Stretching?

improve stretching phasic vs tonic
You can imagine the sensorimotor system is like a radio with controls for bass and treble. You require a balance between the bass and treble to get a sound that is harmonious. By toning down the bass we hear more treble and vice versa. Likewise if we are able to tone down the tonic group of muscles we bring our muscles more into balance allowing the tonic muscles to stretch and improve posture. We can attempt this using the Bruegger exercise.

The Bruegger exercise activates the phasic group of muscles. By using these muscles, through reciprocal inhibition we force the tonic muscles to relax so we can get further into a stretch lengthen the tonic group of muscles and improve posture.

Poor posture can be aggravated by sensory input that affects muscle tone:
  • Stress
  • Pain
  • Joint dysfunction
  • Central nervous system disorder/injury
  • Prolonged postures or repetition of the same activity
  • Overwork or overtraining
What is posture? To think all you need to do to correct your posture is do a few stretches and strengthening is foolish. Our posture and how we perceive our position in space is dependent on the development of the postural reflex system as an infant, how we learn to activate sets of muscles (muscle synergies)during our life time to control posture, sensory input, and responses from the higher centres of the brain to this sensory input. Part of a good postural correction program should also include proprioceptive and balance exercises.