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FCEase Manual

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Postural Tolerance Activities

 

Postural Tolerance Activities

Postural Tolerance is an essential part of any test of physical function.

All jobs or A.D.L.'s have large elements of static and/or dynamic positions within the overall context of the activity.

These have been broken into components of:

  • Standing
  • Sitting
  • Sitting – Reaching
  • Reaching – Overhead
  • Reaching – Shoulder
  • Reaching
  • Stooping
  • Kneeling
  • Walking
  • Climbing
  • Balance
  • Crouching
  • Step
  • Squatting
  • Crawling

 

There may be some positions requiring elements of these in combination and if considered essential, should be included in the test.

Essentially these positions are tested by observation of the position over a period of time. In order to assist in this process, an activity should be offered to the client during this period of observation.

This helps to normalize the procedure in that concentration on the activity will allow a more natural adoption of posture and balance than if the client was merely observed while doing nothing during the time.

The activity can be:

  1. A task requiring manual or mental dexterity to achieve the result

    2.   A standardized test protocol which can be used to add to the results of the F.C.E.

As the equipment inventory increases, the use of some of these standardized tests can not only facilitate the collection of data, but also help define the interpretation of the data collected.

In the meantime use of the simple 'box of bolts' is hard to beat. The range of activities is only limited by the imagination of the evaluator, and can include simple activities such as memory tests, marbles in holes, nuts and bolts and washers and all kinds of puzzles which are easily accessible.

These can be set up according to the position tested and provide a useful means of repeating a test for comparison at a later date.

 

Recording BABI During Tolerance Observations and Testing

 

BABI monitoring is recommended as a useful tool in monitoring the effort used during these tasks. To do this, the following protocol is followed.

  1. Record baseline heart rate
  2. Record time taken for activity – three (3) minutes is recommended time for most activities unless the frequency or length of time in the position at work dictates a longer testing period.
  3. Record heart rate at 30 - 60 - 90 - 120 - 150 and 180 seconds and at 1 minute intervals if the test is longer than 3 minutes.
  4. Calculate mean heart rate during activity.
  5. Subtract baseline heart rate from mean heart rate.
  6. Multiply this by the time, in minutes, to calculate the Beats Above Baseline Index.
  7. Compare this index value to other activities in the order of testing to observe the resultant rises and falls.
  8. The time taken must be a common denominator in comparing values. ie., A three (3) minute activity must not be compared to an eight (8) minute activity unless the Index value has been adjusted to the three (3) minute factor. It is suggested that the last three (3) minutes of the eight (8) minute activity be used for B.A.B.I. purposes.

 

Further to B.A.B.I. - a corresponding graph of pain and perceived exertion values can be superimposed onto B.A.B.I. values to offer the evaluator a unique insight into the physical behaviors during these activities. The interplay of these values along with biomechanical observations can greatly assist in interpreting and recommending abilities for these positions over an eight (8) hour day.

     

Grading of Positional Tolerance Activities

The results must be interpreted by the evaluator using all the data collected.
To assist the reader of the report, the following terminology has been provided:

wpe4F.gif (959 bytes)  Unlimited

These tasks, postures, or positions required can be performed as a function or task for the job required over a normal eight (8) hour day with regulation breaks. The tasks are considered tolerated at a frequent basis by DOT (Dictionary of Occupational Titles) - (more than one time every two (2) minutes). However, if a task, posture, or position must be performed on a constant basis (more than one time every 15 seconds) it is tested for longer periods for the specific work rate required. It is marked as (unlimited +).

wpe4F.gif (959 bytes)  Reduced Tolerance / (Restricted)

These tasks, postures, or positions require frequent postural changes in order to tolerate an eight (8) hour day, but they can safely perform the activity when required. The task is considered tolerated at an occasional basis by DOT (less than one time every two (2) minutes).

wpe4F.gif (959 bytes)  Limited (Impaired)

These tasks, postures, or positions can safely be held, repeated, or performed for periods less than three (3) minutes and for less than three times per working hour (<3 times per hour) during an eight (8) hour day.

wpe4F.gif (959 bytes)  Unable

These tasks, postures, or positions cannot be safely held, repeated, or performed. The client is either UNABLE to safely perform the task, posture, or position or it is not recommended that it be attempted at this stage in a working environment.

N/T Not tested

N/A Not applicable

 

Hint:

Your metronome can also be used to establish cadence of postures which are repeated at a specific rate or at a number of reps per time frame.

 

Standing

Standing posture is assumed to have been evaluated during the initial or subsequent evaluations. The standing tolerance is to be accepted within the context of this posture.

A person who has been assessed as having a normal posture in standing - that is, no gross asymmetries, pelvic tilt, altered weight transference, functional leg length problems, scoliosis or other muscular- skeletal abnormalities, would be assessed for tolerance in two ways:

The estimated standing tolerance as given by the client,

Observed standing postures during testing. Apart from the kneeling, squatting and sitting phases of the test, the client will be standing for about two (2) hours during testing. This gives the evaluator a good opportunity to observe the standing behavior as well as tolerance.

Under normal circumstances this observation and estimated tolerance is adequate. However, if the client is particularly concerned or the job entails long periods of standing (i.e., security guard in a bank or a ticket booth operator or other similar occupations where standing in one spot is the major postural factor) the standing positional tolerance test must then be tested more thoroughly.

Three (3) minute bouts of standing activities can be used to evaluate the postural behavior and tolerances. Change of position, asymmetrical positions shifting of feet and pain reports, all give some idea of the tolerance levels.

These should be assessed in relation and context to the job description. The standing may involve other actions such as operating a register, leaning forward through a window to hand out tickets or change; these positions can be simulated as part of the evaluation.

Sitting

Sitting tolerances can be more difficult to assess as it depends a lot on the type of seat used and the activity being performed. Sitting in a car differs greatly to sitting on a high stool or at a low chair in a pre-school or kindergarten.

Office chairs vary a great deal and it may be advisable if sitting is a main postural factor, to ask the client to bring their 'work chair' to the evaluation.

This again is more a simulated activity rather than a generic test but each case needs to be assessed in context with the job description.

Normal sitting tolerance is done the same as standing using the clients estimation of the task and the observed behavior in the waiting room, filling out forms and during the actual test.

Some assessment of sitting posture is essential in order to make recommendations if sitting tolerance is a limiting factor. This area of the evaluation is clearly dependant on the skills of the evaluator.

Sitting Reaching (optional test)

Many jobs require sitting reaching activities. Most receptionist/clerical positions, drivers, tilers and carpet layers, and teachers, particularly lower school classes, use this position frequently.

The position may be held in a static position or combined with rotation and moving through various heights.

Kneeling

Kneeling involves working at ground level or at very low levels in a position where one or both knees are in contact with the floor.

An optional position may be upright kneeling with both knees on the floor and at 90 degrees with hip extended.

There is a critical position in kneeling where it is difficult for most people to successfully work at floor level without losing their normal lordosis.

Although not an ideal position in which to work, floor level tasks are essential functions of some jobs. It may be useful to examine the difficulties with this position as opposed to working at 10 cm to 20 cm above the floor where most people can successfully maintain normal back posture.

Upright kneeling may be very useful when examining knee or hip joint problems.

While assessing kneeling, note any changes in weight bearing from one leg to the other. In some cases the worker may elect to swap the load entirely from one knee to the other. In other instances the weight bearing change will be more subtle.

Thoracic and neck problems, ankle problems as well as low back problems can limit performance in this position.

Crawling

These postures may be a static or dynamic posture. It involves weight bearing on both hands and knees in order to reach or move at low levels.

This position is often used when working at lower levels for longer periods and may involve gaining access to confined spaces. Posture should include neutral spinal curves. In particular, the lumbar and cervical lordosis should not be accentuated.

 This position may alternate with kneeling as is often seen with carpet-layers. This position may often be limited by knee or wrist problems as well as the more obvious low back disorders. When assessing, note weight bearing symmetry, posture, joint positions and overall ability to perform safely.

Squatting

This position is similar to kneeling as a means of getting the torso to a lower working level.

The difference here is that neither knee touches the floor. This means the weight is taken on other joints in an entirely different manner and is often more difficult to maintain.

In squatting, one knee may be forward but the weight is taken through the other leg, the foot of which is often dorsiflexed under a full load.

An 'Asian' squat position may be chosen where the buttocks are rested on the heels bilaterally and the feet flat on the floor. This position is difficult to maintain for any period and does not adhere well to maintaining a neutral lordosis in the lumbar spine.

The work level can be set at floor level, 10 cm or 20 cm in height depending on the circumstances.

Observations during squatting are similar to kneeling.

Repetitive squatting from standing can be a useful optional test depending on the work situation and the injury(s) involved. An activity requiring squatting to floor level and rising to standing can easily be set up and tested. This may be tested with sustained squatting or incorporated into the lifting pattern to test more fully weight bearing in a resistance-added situation.

Stooping

Stooping is a position present in many forms in the workplace. The key point to the position is trunk flexion. This is tested to some extent in forward reaching position but many jobs involve positions requiring bending over to lower levels.

To successfully work in this position comfortably, factors such as strength and endurance of muscles and the ability of joints to tolerate movement and compression is tested. This position will also test both upper and lower body components making it an essential part of a test of functional ability.

The position of choice is standing and lowering the hands to a level between pelvis and knees. An unloaded activity can be used in this position to encourage the maintenance of this situation. It is essential to attempt to use a SAFE position where at all possible. This is modelled along the lines of the principles of manual handling using elements of trunk stability, hip flexion and knee flexion to help adopt a satisfactory position (see Safe Manual Handling.)

Note the number of times the client rises from this position and the times at which this occurs throughout the testing period.

Hint:

It may help to use an obstacle or rail to 'lean over' while performing this task to accentuate the trunk flexion.

Reaching

Reaching situations occur in all jobs whether it be a pilot on a commercial aircraft or a boner in a meat packing company.

The element of reaching impacts on the torso and back as well as the upper extremities and therefore is an essential test of function.

Reaching in this context relates to forward or upward motions whereas downwards would be covered by stooping, bending situations.

Reaching Forward

Whether tested in standing or sitting will depend on the context of the evaluation and the therapist involved. Standing is a less stable position and probably a better indication of the overall affect. Testing in both positions is an option.

Reaching forward test is carried out at a bench set at work height. The activity is placed between 550 – 650 mm from the edge of the bench to encourage reaching posture.

Posture is encouraged to fall within the five critical demands of:

It is explained to the client that the activity is to be completed within a certain time and that position and body movements are observed. Comments about pain and discomfort are noted and if the client stands erect, note time and ask the reason for the postural change. Foot positions should be noted and any unusual movement patterns should be recorded. Any clumsiness or dropping of items is also noted.

Reaching Overhead

Testing of overhead reaching should be done before shoulder height activities in most cases.

The activity needs to be set at a point close to the top of the head while in a standing erect position.

This will probably preclude good vision so it is a good time to test fingering and handling activities not helped by vision.

This is an area where a standardized activity can be a useful tool. The activity can be timed at bench height and compared to overhead. This will give some idea of the capabilities at different heights.

Note any dropping of arms from this height as well as stance changes or clumsiness or handling difficulties. These can all indicate problems with maintaining this position or may also show inconsistencies with other tests which can be evaluated on completion of the tests.

Reaching Shoulder Height

Shoulder height activity is useful when considering some neck and shoulder problems. This position is often difficult to maintain in some situations whereas it can be much less of a problem than overhead and allow a clear differentiation of optimal work heights if the disability is long term or permanent.

Both reaching to shoulder and overhead positions can highlight postural problems with low back, hip, knees and feet which may not be evident during the lifting due to the time spent in this position and the loading and balance requirements.

Safe Maximal Lift and Safe Maximal Carry - (See equations p. 57)

A unique feature of WorkHab F.C.E. is the ability to test a SAFE maximum lift or carry rather than a one time repetition maximum lift (or 1-RM) and to retest with a submaximal load to check the reliability and consistency of the test.

wpe4F.gif (959 bytes)  Physiology

To do this it is important to understand the physiology involved in this process.

Individuals are capable of working at maximum levels for only very short durations. The ability to exert maximum strength on an external object is a result of:

a) muscular tension

b) mechanical advantage of the lever system

Maximum force can only be exerted for a few seconds before the magnitude begins to dissipate (isometric or static movement). In a dynamic action, the inability to complete the second repetition at the same load after one repetition has been completed is known as one repetition maximum or 1-RM.

wpe4F.gif (959 bytes)  Muscular Strength

For repeated actions, muscular endurance is related to muscular strength on a continuum. A person’s muscular strength will essentially dictate his/her capacity to perform a task repetitively.

Therefore if the force required to overcome a resistance (weight) is reduced, the number of repetitions performed is increased.

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It has been found that a person with a 1-RM of 110 lbs (50 kg) can execute 30 repetitions (30-RM) with a weight of 55 lbs (25 kg). - Doolittle and Kaiyala 1988

Note:

The limiting factors for this type of endurance while not thoroughly understood, appears to be within the neuromuscular system, rather than due to insufficient heart or lung function.

Oxygen Consumption and Energy Expenditure:

Aerobic power is measured by the rate of oxygen uptake or rate of use of oxygen by the body to produce energy.

This is measured in Litres of Oxygen per minute or the standardized unit ml/kg/min. Maximum aerobic power is a measure of a persons' highest capacity for energy production through aerobic metabolism. It is known as:

MET are measurements of energy consumption.

1 MET or Metabolic Equivalent represents resting energy use. Therefore 5 METs equals energy consumption of 5 times resting consumption. 1 MET is equal to 3.5 mL/Kg/min.

Astrand and Rohdahl (1986) include the upper limit of aerobic power that individuals will tolerate over an eight (8) hour day as 30-40% of maximum capacity.

NIOSH (National Institute for Occupational Safety and Health. USA) recommends intensities for an eight (8) hour shift do not exceed 33% of a worker's capacity.

Energy demands relating to these three levels are:

This terminology of occasional, frequent, and constant is very broad and ambiguous particularly when applied to a job with many varied tasks.

A person whose job is basically sedentary may have to undergo a repetitive task consisting of 10 reps/min for 30 minutes once a week. Under these broad guidelines it would be classed as occasional usage.

Physically demanding tasks requiring fewer than 6 reps/min usually rely on a person's strength capacity [an anaerobic energy system (without oxygen)]. Physically demanding tasks requiring greater than 20 reps/min rely on a person's aerobic capacity. Between 6 and 20 reps/min rely on both these capacities.

This equates with the well known nomenclature adopted by the U.S. Department of Labor for Physical Demands.

Occasional Demand - up to 33% of the time.
Frequent Demand - 33% to 66% of the time.
Continual Demand - 66% to 100% of the time.

Using repetitions/minute or repetitions/hour is much more accurate and can provide a better profile of a worker’s tasks so that the F.C.E. can be more accurate in pinpointing at-risk tasks.

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