28 MECHANICAL PARAMETERS – WORK POSTURES, POSTURAL VARIATION AND DISCOMFORT

Geetha Suresh

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1.0 Introduction:

 

An interesting topic for designers, students working on interior space planning and employer’s prime consideration while designing the layout of their work premises. Work Postures, Postural Variation and Discomfort are interrelated topics.

 

2.0 Objectives:

 

At the end of the module, the student wasexpected:

  • To understand the different work postures and the discomforts created.
  • To understand the right postures for working.
  • To equip the students about Postural Variations and its impact on health conditions.

3.0 Introduction to Posture:

 

The mechanical parameters in postures are related to various positions of the body parts and its alignment. A definition of a type of posture denotes a characteristic combination of the parameters considered. Such posture typologies generally relate to specific professions and are characteristic to them.

 

Let us discuss the major parameters that are related to the design and postures. Let’s try to understand the basics of the postures, its influence on the health and discomfort and the postural variations which lead to better movement.

 

3.1Posture :

 

What is a Posture?

 

Posture is not a position, but a dynamic pattern of reflexes, habits, and adaptive responses to anything that resists being more or less upright and functional. Such as:

  • Gravity
  • wkward working conditions (which may be unavoidable)
  • Abnormal anatomy
  • Athletic challenges

A Good Posture is an attitude which is assumed by our body parts to maintain stability and balance with minimum effort and least strain during supportive and non-supportive positions.

 

A good posture is probably “dynamic,”and emphasizing a change in the movement. Keeping the body active, frequently changing our postures, and experimenting with diverse ways of moving through, are probably good responses to the uncertainties of posture.

 

3.2 Meaning and Definition of Posture:

 

Posture is a static state – ‘A position of the body’ or ‘An attitude’ (dictionary.com), ‘Posture is arrested movement’ (Bobath). In a Human body, the bones hold us up, the joints link the bones, the muscles move the bones around the joints and our nerves facilitate control of the whole.

 

The Definition of Posture:

 

The position or carriage of the body in standing or sitting, often specific, with respect to the proper alignment of the back, shoulders, and head such a position assumed as in posing for an artist the way things stand; condition with respect to circumstances: the delicate posture of foreign affairs an attitude of mind; frame of mind an attitude assumed merely for effect an official stand or position, as that taken by a nation on a major issue.

 

3.3 Types of Postures:

 

Static postures (or “static loading”) always refer to physical exertion in which the same posture or position is held throughout the activities. These types of exertions or activities put increased loads or forces on the muscles and tendons, which contributes to fatigue and discomfort.

 

The static load exertion occurs in human because not moving impedes the flow of blood that is needed to bring nutrients to the muscles and to carry away the waste products of muscle metabolism. Examples of the static postures are gripping tools that cannot be put down, holding the arms out, up to perform tasks, standing in one place for prolonged periods.

 

The effects of postural changes in the body from doing tasks that require long reaches are exacerbated where the reaches must be maintained for more than a very few second. Holding the extreme postures places very high static loads on the human body results in early fatigue. The blood flow that is needed for tissue recovery and muscular effort to do the task is also affected due to the lack of motion or the static posture. When a person stands or sits longer or more of static motion, the risk of injury is higher and it happens due to overuse of muscles, joints and other tissues.

 

Dynamic posture is the other form of posture where it simply denotes the position of the body at the moment of action or movement pattern. In other terms, Dynamic posture means it is essentially a snapshot of the body movement whereas when the snapshot is always the same (as the person is in the static position), is the static posture.

 

Neutral posture iswhen the body posture is in the neutral position, meaning the joints are not bent and the spine is aligned to the body position and not twisted. Working in neutral postures is preferable to maintain a perfect good posture.

 

Awkward posture also refers to positions of the body awkwardly as the term denotes. The positioning of the body deviates significantly from the neutral position while performing any work. In the Awkward Position, muscles operate less efficiently and more force must be expended to do the task effortlessly.

 

3.3.1. Correct Posture Versus Slump and Rigid Posture:

 

 

Easy or Correct Posture- It’s the neutral one, Symmetrical and balanced Position Slump or Fatigue Posture- It’s the Asymmetrical or Sagging Posture

Rigid Posture (also known as Posture of attention)- It’s the habitual positioning that causes unnecessary strain on the body.

 

3.4 Effect of Postures:

 

Human Posture is the position of the body while performing various work activities. As we know by now the more some joint deviates from the neutral or natural position, the greater the risk of injury. Posture issues are created by varied work methods like (bending and twisting to pick up a box or bending the wrist to assemble a part), the workplace dimensions also creates the postural issues like the extended reach to obtain apart from a bin at a high location; kneeling in the storage bay of an airplane because of confined space while handling luggage.

 

Common Specific postures that have been associated with injury are:

 

1.      Wrist

2.      Flexion/extension (bending up and down)

3.      Ulnar/radial deviation (side bending)

4.      Shoulder

5.      Abduction/flexion (upper arm positioned out to the side or above shoulder level)

6.      Hands at or above shoulder height

7.      Neck (cervical spine)

8.      Flexion/extension or bending the neck forward and to the back

9.      Side bending as when holding a telephone receiver on the shoulder

10.  Low back

11.  Bending at the waist, twisting

 

3.4.1 Good Posture:

 

A good posture helps the muscles in the body to be relaxed and less loaded. Maintaining good posture has its value in our body functions and systems. The effects of good posture are that it improves respiratory and circulatory efficiency, prevents body from unnecessary strain, stress and fatigue. It also decreases the diseases caused by the bad posture which ultimately helps to improve the mental and psychological state of mind.

 

3.4.2 Poor posture:

 

When the joints, muscles and nerves are not aligned in neutral or map-alignment, results in poor posture.

 

Causes of poor posture–

 

A classic example of poor posture, which most of us do is, sitting hours together with the knees tucked sharply under the chair. We never realized that it hurts the knee caps and the lack of awareness of our postures results in the map-alignment or in other words the awkward/poor posture.

  Why arewe humans prone to poor posture? There are two sides to this: physical and mental.

 

Physically, we follow our forefathers’ life style of bending and plucking or hunting in search of food, which we no longer do what we evolved to do. The other one is, our body is not emphatically not designed to spend the day sitting staring fixedly at a computer screen or mobile phones or the modern terminology known as couch potato or in a car seat staring at the road ahead, or for any of the other activities of our modern life that are so far from our origins.

 

What are the physical risks of PoorPosture?

 

Poor posture contributes to the formation of knots in tired muscles. Trigger points seem to be closely associated with a wide variety of other common pain problems. In ordinary conditions, many aches and pains suffered by humans, especially low back pain could result in reduced efficiency and economic productivity and an even greater unmeasurable cost to quality of life.

 

Mentally, we have unnatural pressures that bear on us all the time and today’s life is complicated by the sheer variety and duration of circumstances and information that affect us. Thus a person with stress from job, work pressure and lifestyle living with poor nutrition tend to have a worn-out demeanor with the posture like a round shoulders and a curved spine etc.

 

What are the (emotional) risks of poor posture?

 

Poor posture can get us into an emotional rut. It is the Comfort Zone problem. we all know that Posture is shared by mood and all kinds of other social and emotional factors. posture might create and reinforce emotional states if posture can influence emotions, it could also change pain sensitivity. Emotions, posture, and pain sensitivity probably do all influence each other to some degree. Most self-limiting behaviors have both postural effects and causes.

 

Postural Strain versus Poor posture

 

Postural Strain could be due to carrying a heavy backpack slung over one shoulder and we think it is a circumstance that makes it difficult to be comfortable or to maintain as a good posture. Same way typing incessantly is a postural strain. It’s not a bad habit, it’s something that some of us have to do and it is a challenge to our bodies.

 

3.5 Images of Do’s and Don’ts:

4.0 Postural Variations:

 

 

Postural Variations is nothing but the essential movements of the body positions by avoiding a fixed working posture. The Variations could be achieved through different forms.

 

4.1 Workflow:

  • Always Rotate between several types of work tasks as frequently as possible.
  •  Plan and Break up repetitive tasks with other tasks, i.e. use of different muscle groups; do paperwork, brainstorm, schedule meetings or pick up mail in between periods of sitting in front of computer work.
  • Set time limits for certain tasks; i.e. schedule phone calls after one hour of sending emails.
  • Move between dedicated work zones with adequate space to support different work tasks.
  •  Make sure to walk for minor jobs, like place your printer/ or coffee machines etc. furthest away. from your desk. Same way, Place filing cabinets and waste/recycling bins far away so you need to get up to use these.
  • Set reminders over Phone to take compulsory breaks while working on projects and deadlines.

4.2 Postural breaks:

  • Move or stretch for few seconds every hour; and use a timer as a reminder.
  • Do simple Relaxing exercises to your hands and shoulders when waiting for your computer to load.
  • Keep alternating your positions like stand to think for a few moments when possible before responding to an email.
  • Take a quick movement break to stimulate or settle your thoughts.
  • To improve the circulation, keep rolling your shoulders, fidget, and move your feet and ankles. Drink more water to stay hydrated throughout the day and always walk and go to get water.
  • Keep Changing your position or posture often for your comfort and to offset the fatigue.
  • Keep away from Computer and phone during work breaks and use the break for enjoyable activities.
  • Get up and walk to dining place to have your lunch.
  • Always know your limits and keep a tab on yourhabits, to make effective changes

5.0 Discomfort:

 

The postural discomfort is observed when the joints are used in different form from the actually designed position. In other words, we say it as “out of Alignment’, which causes discomfort and can manifest as pain and gradually become an injury.

 

The degree of mal-alignment predicts the level of stress and injury. The lesser the degree, the effect is not immediate serious, whereas, the greater the mal-aligned or postural discomfort, the effect is instantaneous. If a joint is both mal-aligned and under stress, can mean quickly or over a period of timean ensured break or a tear.‘If the stress level is at lower degree but in repetitive nature, it could cause strain injury in any part of the body.

 

Mal-alignment leads to muscle imbalance. Though Muscles adapt well, but when the arms are held in wrong position over a period, it creates round backs or slumped shoulders.

 

5.1 Remedial actions for posturediscomfort and pain:

 

The basic three steps or to question ourselves are:

 

1.Understand that you can take control: Always understand your body mechanics, your work place and the environment. Take control of the situation and work towards it.

2.Listen to the Body:The most important remedial measure is listen to your body. In nature, certain posture is designed for certain activities. when you feel slightly discomfort, change the posture or take a break from the activity and continue.

 

3.Take action:If the postural discomforts and pain are a repetitive process, then advised to take a serious action. Change the work environment, or the seating chair, the gadgets used could be redesigned for the individual comfort zone. Most of the time the convention ergonomics design the zone but not give importance to the subject. It is always necessary in ergonomics, the work on “You”first, that is, the subject or the human interface with the environment. If a subject complains of the postural discomfort, it could be of many reasons. First look at the individual needs, take action and then work on the overall environment.

 

Few Suggestions for Postural Discomfort and remedy for pain:

  • Imagery:Imagine that a straight line passing through your body from ceiling to floor vertically and think that a string or cord is attached to your body from top to bottom. Try to hold your pelvis level without swaying the lower back and resist the urge to stand on tiptoe. These Imagery pictures help you to keep up your posture and avoid the pain on longer run.
  • Shoulder Squeeze:Same way try to sit up straight in a chair with your hands resting on the thighs. Do simple exercises like squeezing your shoulder blades together and repeat them.
  • Upper-body stretch: Stand facing a corner with your arms raised, hands flat against the walls, elbows at shoulder height. Place one foot ahead of the other. Bending your forward knee, exhale as you lean your body toward the corner. Keep your back straight and your chest and head up. You should feel a nice stretch across your chest. Hold this position for 20–30 seconds. Relax.
  • Arm-across-chest stretch: Raise your right arm to shoulder level in front of you and bend the arm at the elbow, keeping the forearm parallel to the floor. Grasp the right elbow with your left hand and gently pull it across your chest so that you feel a stretch in the upper arm and shoulder on the right side. Hold for 20 seconds; relax both arms. Repeat to the other side. Repeat three times on each side.

         To understand the discomfort the postural assessment could be done and the evaluation of each individual will resolve the discomfort and pain. The sample postural assessment tool is given below.

 

6.0 Summary:

 

The Posture, Postural Discomfort and Variations are different for each individual and it varies with different work environment. The role of Ergonomics in the effect of posture study is very important, but unfortunately people look the postural discomfort with ergonomics in few aspects like change of seating chairs, or tilting the key boards or increase the illumination. But its beyond that and much more.

 

A proper study of Ergonomics is the science of arranging or designing things for efficient use, specifically to avoid these types of postural strain. A variety of postural behaviors will also help to strike a balance between the path of least resistance and obsessive and excessive effort, neither lazy nor overzealous.

 

For any individual, the comfort zone of their needs is the best posture, but do not linger on the same position for a longer time.

 

Posture is almost certainly associated with some pain problems, but not very serious as most of us believe. If the Postural habits with clear consequences and easy fixes are taken into consideration the postural problem can be avoided.

 

Hope you could understand by this time the concepts of posture, the discomforts caused by bad posture and few postural variations could relieve the pain point. In the next lesson let’slook into the Environmental Parameters affecting work efficiency.

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References:

  1. .http://www.businessballs.com/workplaceposture.htm
  2. .https://www.painscience.com/articles/posture.php#sec_what
  3. https://ergoweb.com/knowledge/ergonomics-101/concepts/
  4. Stephen Pheasant, Christine M. Haslegrave, 2006, Body Space ,Taylor and Francis Group,

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