Posture and Body Mechanics
PTA 101 Intro to Clinical Practice 1

Instructional Use Statement

The following information is used for instructional purposes for students enrolled in the Physical Therapist Assistant Program at Lane Community College. It is not intended for commercial use or distribution or commercial purposes. It is not intended to serve as medical advice or treatment.

Contact howardc@lanecc.edu for permissions

Lecture Objectives

Specific Lesson Level Objectives include:

1. Define the term body mechanics
2. Define and describe terminology used in assessing and evaluating body mechanics
3. Describe proper body mechanics to use for lifting, reaching, pushing, pulling, and carrying objects
4. Explain specific precautions to use when lifting, reaching, pushing, pulling, and carrying objects
5. Describe how posture impacts body mechanics in a given case situation

Key Terms

• Static - when the body is at rest, or still
• Dynamic - when the body or body segments are moving (e.g. during a functional activity)
• Base of Support (BOS)- area of the body in contact with the supporting surface
• Postural control - ability to maintain stability in a particular context (i.e., environment). For example, sitting on a stool vs. sitting on a standard chair requires different postural control in the trunk

• Center of Gravity (COG) - a single point in the body which represents where the entire weight of the object is centered; the point at which all parts of the body balance each other. The COG will change based upon positional changes.
• Limit of Stability (LOS) - the greatest distance in any direction a person can lean away from a midline vertical position without falling, stepping, or reaching for support.

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• Neutral posture - COG is positioned over BOS
• Poor posture - strain to body parts resulting from inefficient balance over BOS
• Line of gravity (LOG) - vertical line positioned through the body's COG. Also referred to as the Vertical Gravity Line (VGL)
• Anatomical position - universal reference position or anatomical planes
• REVIEW and be prepared to CORRECTLY IDENTIFY the general anatomical reference points below
• anterior
• posterior
• dorsal
• ventral
• palmar/plantar
• medial
• lateral
• proximal
• distal
• sagittal
• frontal
• transverse
• cephalad/superior
• caudad/inferior

•  Ground reaction force (GRF) - Force exerted back on the body by the ground
• Lordosis - inward curve at spine (normal resting position of cervical and lumbar segments)
• Kyphosis - outward curve at spine (normal resting position of the thoracic segments)
• Scoliosis

Posture

Advantages of Neutral Posture

• Minimize injury risk
• Minimize structural changes (e.g., deformities)
• Allows for optimal muscle and organ function

 Impaired Posture

The supervising PT may indicate "impaired posture" in a patient problem list and include goals related to posture (static and dynamic) in the plan of care.

For example, a patient with a medical diagnosis (pathology) of osteoporosis may present with impaired posture (increased thoracic kyphosis), which impacts pain and endurance for standing and walking.

Treatments for impaired posture include effecting a change in muscle length and strength and adapting for fixed, structural changes.

Muscles change length and muscle fiber type changes over time due to habitual postures, under use and misuse of structures. Shortened muscles become stiffer, less likely to respond to stretch, and the cycle continues.

A little asymmetry is normal. For example, in standing the dominant hand (i.e., left or right handed) is typically lower with reference to the acromion than the non-dominant hand. This is generally attributed to more developed (i.e., larger) muscles on the dominant side. This can then be compensated for by a higher pelvis on the non-dominant side.

Many large muscles cross multiple joints. Therefore, an over-lengthened or shortened muscle can influence the resting postions throughout the spine, pelvis and extremities.

Common faulty postures include: kyphosis-lordosis, sway back, and flat back

Active Learning: See if you can apply your knowledge of anatomical planes and observational skills to describing changes at the spine, head and lower extremity

Click here for an example of how posturography is used with tablet applications (e.g. PostureScreen) to assist in assessing posture. How would you document your observations of these postural asymmetries?

 Role of the PT and PTA

Specific interventions for posture are introduced in Kinesiology. In this class, we set the foundation for postural assessment by ensuring you are able to recall anatomical planes, movement planes, and begin working on observation and documentation of those observations in static (non-moving) positions.

PT Examination and Evaluation

Posture is a component of every PT examination, regardless of pathology. The PT is responsible for establishing or elaborating on movement/activity precautions, contraindications, safety considerations, and differentially diagnosing the role of posture as a primary impairment contributing to functional limitations and disability. The PT documents postural observations in supine, sitting, standing, and/or functional activities depending on the patient's level of function at the time of the assessment. Muscle atrophy, hypertrophy, spasm and symmetry are noted, along with the postural impacts of ligamentous laxity, footwear, and assistive devices.

PTA Tests, Measures and Intervention

PTAs review the medical record and reassess posture using observations and patient instruction.

PTAs follow up on safety considerations and evaluate the patient and situation for ability to safely participate in postural interventions

PTAs can assess muscle length using multiple intervention strategies. PTAs provide exercise instruction, make recommendations for activity, equipment and workplace modifications in order to optimally affect modifiable contributors while minimizing stress to non-modifiable contributors to impaired posture.

PTAs make comparisons between the patient's current status and their baseline postural examination in order to determine if there is progress or if there is some barrier to progress which required further assessment by the supervising PT. PTAs actively listen to patients and relay information (through documentation and meetings) about additional contextual factors impacting progress.

PTAs document preferred posture and postural observations using appropriate medical terminology. PTAs document progress toward postural goals so the PT and the health care team are well-informed of the patient's participation, response, compliance, and safety throughout the treatment plan.

Boxes 4.5 through 4.9 in Pierson outline some clinical examples of how principles of postural control are integrated into patient education and exercise recommendations.

Key Terms - Body Mechanics

"Body mechanics can be described as the use of one's body to produce motion that is safe, energy conserving, and anatomically and physiologically efficient and maintains body balance and control." - Pierson & Fairchild, Principles and Techniques of Patient Care, 5th Ed.

PTs and PTAs apply their knowledge of posture and how forces act on the body to teach and practice proper body mechanics. Why? Because PTs and PTA do a lot of lifting, stooping, carrying, bending, standing, kneeling, sitting, and squatting during patient care activities. Our patient's and clients are at risk for injury or reinjury during healing if everyday movements are not balanced and efficient. Repetitive microstrain leads to tissue failure, pain, loss of work, and risk for permanent disability. For a long, successful, and healthy career, we start with learning how to protect ourselves so that we can teach others how to recover from or prevent injury.

Body Mechanics Basics

For each situation, consider the effects of gravity (VGL) and friction when performing an optimal push, pull, lift, and carry.

Take home messages for body mechanics are succinctly stated in Procedure 4-1 of Pierson

• Vigilantly avoid breath holding while preparing to lift, push or pull. Breath holding while exerting effort is called a Valsalva Maneuver. Increased pressure in the thorax can significantly stress and/or injure the heart, large vessels, and intervertebral discs.
• The further the object is from the center of gravity (longer lever arms), the heavier it becomes. Heavy objects take more energy and strength to manipulate than lighter ones.
• When lifting an object, assess its center of gravity. Try lifting and holding from there so there are minimal rotation forces from gravity (see golf clubs in car above)
• Widen your base of support and position your legs in the direction of the motion when pushing/pulling. This will allow you increased stability while overcoming friction and gravitational forces.
• For standing activities that require rotation: lift feet and step to turn versus keeping feet planted while twisting. When the arms and legs go together, spine stress is minimized
• Locking the knees/elbows into full extension results in increase flexion forces in the spine (and interverterbral discs) and shoulders/neck respectively.
• When providing patient care at the bedside, take time to set up the treatment area to minimize your risk for injury: assess how much your patient can help, give clear directions, facilitate bringing the patient as close to you as possible to decrease torque to your spine during PT interventions.
• If there is equipment available to help lift and carry, USE IT. Examples are patient lifts, dollies, rolling carts, rolling casters (wheels) on hospital beds, foot pedals or manual cranks for adjusting bed/mat height, foot stools/step ladders, second or third person assist, etc. Prepare and be aware of your limitations and environmental constraints. Rush and take short cuts: someone (perhaps you?) is likely to get hurt.

Remember: gravity is POWERFUL. Do what you can to minimize the effects of gravity and you will minimize your risk for injury.

The 6 "L"s of Lifting

1. LOAD - Always test the load. If it is too heavy, get help
2. LEVER - Keep the load close to spine when in an upright position
3. LORDOSIS - Maintain the low back in its anatomical position to protect discs, ligaments while lifting. Flexed spines put pressure on the posterior disc resulting in greater risk of herniation
4. LEGS - Let your gluts, quad, and calf muscles do the heavy work. That's what they are made for!. Position legs for optimal base of support. Pick up your feet to turn...NO TWISTING. Make sure feet are free to move and change position so you can adjust your base of support as needed
5. LUNG - Set abdominals and exhale as you lift. Breath holding can be dangerous!
6. LOOK - Your head should lead the lift. Once you have a hold of the object, keep that head and chin up.

Common Lifting Mistakes

• Lifting with flexed spine and the legs straight
• Using a fast jerky movements
• Bending and twisting at the same time
• Poor planning
• Poor communication
• Insufficient strength

Lifting Options

These specific lifting techniques will not be on your exam, yet are listed here for your reference in preparing for lab practice.

A little more about overhead lifting

1. When possible, use a step stool when the target surface is higher than your head
2. Slide objects in and out of the overhead area
3. Shift your body onto your front foot when lifting an object

Accomodations for Optimal Lifting and Carrying

PTs and PTAs assess strength, ROM, motor skills, pain, and function during body mechanics training activities. If proper posture or lifting can not be performed by an individual, we work to modify and accomodate limitations so there is minimal risk for injury and optimal efficiency.

After reviewing proper posture and lifting mechanics, self-assess your own readiness to perform lifting tasks:

• Do I have full ROM in my trunk and extremities?
• Can I squat, bend, and lift overhead without difficulty?
• Can I plan and sequence lifting to minimize my risk for injury?
• Do I have a previous injury or other condition that may impact my ability to safely lift, push, pull, or carry?

If the answer to any of the above is "yes", consult with your instructor prior to engaging in lab practice.

End of Lecture

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