The Importance of Posture and Why We Should Assess It

It is accepted industry practice, by both fitness and allied health professionals, to incorporate a postural assessment in pre-screening procedures. Why then, do we still see fitness professionals that neglect this practice? Is it because they do not see the value in taking the time required for an in-depth observation of posture? Perhaps a better understanding of the importance of posture and how addressing postural anomalies can enhance both customer service and client outcomes will lead to greater importance being placed on this practice by all fitness professionals.

What is Posture?

Posture, defined at its simplest, is the series of positions in which you hold your body upright against gravity. 

Ideally posture involves holding your body in the optimal position such that the least strain is placed on joints, ligaments and muscles, as you stand, sit, lie and move. This encompasses both static and dynamic posture, both of which should be assessed by fitness professionals as part of the client pre-screening process.

Is There an Ideal Posture?

You will often hear people talk of ‘good’ and ‘bad’ posture. However ‘good’ posture is more individualised and varied than literature might suggest. We are all unique and this individuality extends to our posture. The body positions that represent your ideal posture are likely not the same as those that represent another person’s posture. Our posture is dependant on many factors including:

• Body size
• Height
• Weight
• Length of levers
• Muscle mass
• Muscle length

Healthy posture for an individual is the correct alignment of body parts supported by the right amount of muscle tension against gravity. It requires minimal effort and energy expenditure to maintain.

Optimal Joint Position

While it can not truly be said that there is an ideal posture for all individuals, there is a standard for optimal joint position that is widely recognised and used for the purpose of static postural assessment by both fitness and allied health professionals. It is as follows:

• Ears over shoulders
• Scapulae 5cms from midline and against ribs (2-7)
• Counterbalancing spinal curves – cervical and lumbar lordosis and thoracic and sacral kyphosis
• Slight anterior tilt of the pelvis (6-7 degrees)
• Angle of femur to tibia (Q angle) relatively straight (greater in females than males)
• Ankle neutral  – achilles tendon vertical.

Line of Centre of Gravity

To better understand posture we need to consider the line of centre of gravity. First it is helpful to note the following definitions.

Centre of Gravity – The average location of the weight of an object, evenly distributed in all directions. This changes with change of position.

Centre of Mass – The point at which mass distribution is equal in all directions independant of gravitational field. In the body this is the second sacral vertebra.

Line of Centre of Gravity – An imaginary vertical line from the centre of gravity to the ground or surface an object or person is on.

Note that when we stand, we tend to naturally shift our weight from side to side, placing most of our weight on one leg. When we assess static posture we use a relaxed bilateral stance. In this position, where the line of centre of gravity falls governs the amount of muscular effort required to maintain the position.

In the human body, ideally the line of centre of centre of gravity through the centre of mass falls close to but not through the joint axes:

• Approximately 5cms in front of the ankle joint
• Just in front of the centre of the knee joint
• Through the hip joint or just behind it
• Just in front of the shoulder joint
• Through the mastoid process

The line of centre of gravity of the body remains close to the centre of the base of support, just in front of the ankle joints. As this line shifts outside of the base of support, stability decreases and muscular effort must increase to prevent the effects of gravity – falling. 

Muscular Activity to Maintain Posture

Where the line of centre of gravity falls determines muscular activity either side of the joint to maintain posture. Using electromyography (EMG) scientists can measure muscle activity in a bilateral stance. EMG measures the electrical activity in a muscle in response to stimulation by a nerve. EMG studies show that in bilateral stance, with the line of centre of gravity just in front of the ankle joints, active muscle contraction for balance is required only in Gastrocnemius and Soleus, with greater activity in Soleus. This activity prevents you from tipping forward. There is also a small amount of activity in the Hamstrings to prevent knee hyperextension and Iliacus, as the hips are not in complete extension.

In most individuals there is no EMG activity in the Quadriceps during relaxed bilateral stance, apart from short bursts during postural sway when the line of centre of gravity falls momentarily behind the axis of the knee. This prevents you from falling backwards.

Benefits of a Healthy Posture

If you can find and maintain your ideal individual posture during activities of daily living you will see improvements in your energy, pain levels, fitness levels, skill progression and athletic performance. Healthy posture:

• Improves bone, joint, ligament and muscle health
• Decreases abnormal wear on joint surfaces – articular cartilage and bone
• Decreases speed of degeneration of the spine and other joints
• Decreases stress on ligaments, especially spinal ligaments 
• Improves joint range of motion
• Alleviates compression on nerves and the vasculature of the body 
• Decreases fatigue as muscles are used more efficiently and less energy is expended
• Prevents or decreases muscle strains, overuse disorders, back and neck pain
• Increases stability and balance
• Decreases injury
• Improves breathing
• Improves mood
• Improves physical appearance
• Improves confidence

Causes of Unhealthy Posture

The most common causes of unhealthy posture are:

• Habitual postures – caused by poor ergonomics or vocational demands 
• Repetitive motions – associated with work, sport and other recreational activities
• Poor biomechanics – as a result of genetics, injury or habitual movements
• Genetic conditions
• Injuries – leading to compensatory movements
• Muscle imbalances 
• Fatigue
• Stress

Why Assess Posture?

We have established that, to some extent, posture is unique to each individual, so why assess it?

Healthy individuals have the capacity to tolerate musculoskeletal stressors on a daily basis. Every day we adopt habitual postures that place increased force on muscles, bones and connective tissue that may lead to imbalances. These postures all cause postural strain. The challenge is to recognise that strain and change our position. Many of us miss the cues that our bodies give us when this strain exceeds the strength of the structures that it is placed on. By the time we realise it, we have pain. 

A thorough static postural assessment, along with the assessment of dynamic posture through a functional movement assessment, can detect imbalances early, before a person is aware of them and before they experience pain or injury. Once detected, imbalances can be addressed with well designed individualised exercise programming, incorporating corrective strategies.

To attempt to design a program for your client without conducting a static postural assessment is like flying blind or missing a crucial piece of a puzzle. At the very least you are not designing a program that will provide your client with optimal results. At worst you are placing your client at an increased risk of injury. It is your responsibility as a fitness professional to ensure the safety of your client and to make every effort to assist them to achieve the best possible training outcome. This begins with comprehensive prescreening, including a detailed postural assessment.

Conclusion

While we could explore the correct procedure for conducting a static postural assessment, the key observations to incorporate, common anomalies  and how to effectively apply corrective strategies in program design, this is best left to a separate discussion. Although only a very brief exploration, I trust that we have clearly defined what posture is, its effect on the overall well being of an individual and why it is so important to carry out a thorough postural assessment on all clients.

References

• Galley, P.M & Forster, A.L. (1982). Human Movement: An Introductory Text for Physiotherapy Students, 76-86
• Norkin, C & Levangie, P, (1983). Joint Structure and Function: A Comprehensive Analysis, 369-371, 374-380.
• Roy, S. & Irvin, R. (1983). Sports Medicine: Prevention, Evaluation, Management, and Rehabilitation, 270-271.
• https://www.acatoday.org/patients/posture/
• https://www.acropt.com/blog/2017/8/16/posture-introduction
• https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/posture
• https://www.health.harvard.edu/staying-healthy/why-good-posture-matters
• https://www.lifespan.org/lifespan-living/posture-and-how-it-affects-your-health
• https://www.lompocvmc.com/blogs/2021/april/importance-of-good-posture/
• https://mayfieldclinic.com/pe-posture.htm
• https://www.peak-physio.com.au/good-vs-bad-posture-an-outdated-paradigm/
• https://www.stasisrehab.ca/blog/what-is-posture/

• Bio

Jennifer Bryce

After completing her fitness qualification with AIF in 2007, Jennifer entered the industry with a desire to serve her local rural community by providing access to high quality personal training. After a year gaining experience at Fernwood, she launched her own Group Outdoor Personal Training franchise business. She successfully operated this for seven years before selling it to pursue her interest in corrective exercise and rehabilitation. She opened her own home studio in 2016, specialising in training clients recovering from both acute injury and chronic pain and dysfunction. For many years now, she has worked toward the goal of using her extensive knowledge and experience to educate and inspire the future generation of fitness professionals. Her role as Trainer and Assessor with AIF brings that goal to fruition. She is dedicated to supporting and encouraging AIF students and passionate about seeing them enter the industry well equipped and ready to make a true difference in the lives of their clients.