Chapter 7

Methods of Classifying and Evaluating Manual Work

Traditional Methods

Historical Perspective:

• Describing manual activities with reference to standard categories of effort was traditionally used to classify and evaluate manual work.

• Based on improving efficiency without major concern for safety

Worker is secondary to the task

Early years

• 1880s• Frederick Winslow Taylor

• Time studies of Philadelphia steel making. • Stopwatch

• “Taylorism”• Scientific ways to measure and control industrial workers

• “how” and “how fast” a task should be done

• Labor leader reaction: eliminate “personality, intelligence, even the very desires of the worker”

Solnit, Rebecca (2003). River of Shadows: Eadweard Muybridge and the technological wild west. p 212.

Later early years

• 1900s• Frank Gilbreth

• Study and streamline industrial activities• Motion study photographic techniques and motion pictures

• Applied “Taylorism”• Dissect motion to understand and control it

• Labor reaction: denies the need of the body.

Solnit, Rebecca (2003). River of Shadows: Eadweard Muybridge and the technological wild west. p 212.

Later early years

• 1900s• Frank Gilbreth

• Study and streamline industrial activities• Motion study photographic techniques and motion pictures

• Applied “Taylorism”• Dissect motion to understand and control it

• Labor reaction: denies the need of the body.

Solnit, Rebecca (2003). River of Shadows: Eadweard Muybridge and the technological wild west. p 212.

$$$$$$$$

Contemporary Biomechanical Job Analysis Systems

• Worker is critical importance• labour costs are significant portion of payroll• labour determines quality of output• injury costs are significant potential source of saving

(reduction not less treatment)

• Fit worker into ideal task• cognitive• anthropometrics• physical skills

• Consider environment effectsBased on Sciencenot “rule-of-thumb”

Contemporary Biomechanical Job Analysis Systems

• Physical stress checklists and surveys• Reactive (after the fact)

• validity? reliability? objectivity?• will employees open up? consequences?

• Injury history throughout workplace• indicates where in-depth study is warranted

• overhead of cumulative trauma• Physical assessment survey• Psychophysical scale: just ask ‘em• Keyboard injuries• Back pain overheads article by Burchfiel et al, 1992

• initiate discussion between employee-employer

Cumulative Trauma

Physical AssessmentSurvey

Tips: Get Re-leaf from Raking PainOctober 12, 2007Note similarity to advice given to “athletes”

AT this time of year many homeowners will be getting their exercise by raking leaves. Raking is a physical activity that can help individuals stay active, but raking is often accompanied by the strains and pain associated with repetitive motions. Fortunately, raking injuries can be prevented by following a few guidelines. The Canadian Physiotherapy Association (CPA) recommends that people pace themselves, use good posture and body mechanics, and adopt a good technique for raking."Many people plant their feet, then over-reach and twist to rake in several directions from that position," said physiotherapist Robynne Smith of Off Broadway Physiotherapy & Dizziness Clinic in Saskatoon, Saskatchewan.It is important to maintain a good posture by changing your position and avoiding bending and twisting. Improper technique often leads to strains of the mid and lower back," she added. "The repetitive strain of raking can be reduced by doing warm-up and cool-down exercises, using proper techniques, and by splitting the job into 20 to 30 minute segments."The following recommendations from the Canadian Physiotherapy Association will help minimize the risk of strains and sore muscles:Before Raking:Be proactive about your health by staying fit and engaging in regular exercise so that household activities, like raking, won't take as much of a toll.If you have back pain that limits your activities, ask for help from family members or neighbors, or hire someone to do it for you.Consult a health professional if you have any pre-existing health concerns.It's helpful to do warm-up exercises for the larger muscle groups such as the shoulders, back and the legs before all yard work.Raking:Pace yourself by completing the work in 20 minute to 30 minute segments. Take frequent breaks and/or change to a different raking activity.Hold the rake handle close to your body to help maintain good posture while raking. Keep one hand near the top for better leverage and use your arms and legs more than your spine. Ergonomic rakes often have padded handles to reduce strain on the hands and wrists, and have special handles that encourage good posture by ensuring that the elbows are bent slightly.Change sides frequently and avoid twisting from the waist. When raking, the tendency is to plant the feet in a fixed position and rake in several directions from that position. Instead, place one foot ahead of the other which allows you to shift forward and backward easily as you rake.Bagging:When bagging leaves, lift manageable loads. Keep your back straight and use your legs to do the lifting. If you have to stoop, face the pile of leaves and don't twist as you lift.Don't try to overreach to get those last few leaves.When lifting the bag of leaves, tense your stomach muscles to give your back additional support and keep the bag close to the body. Keep your back straight while lifting with the legs.Don't pile too many leaves into one bag, especially if they're wet -- it will be heavy and awkward to lift.When finished for the day, take a few moments to cool down by doing the same exercises performed prior to raking.

Psychophysical Scale

Keyboard injuries

Burchfiel et al (1992)

Abstract

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Burchfiel et al (1992) Prevalence of back pain and joint problems in a manufacturing company (#1753)

• Have you ever had any pain in your back or joints during the past year?

• During the past year, have you had back pain for more than 30 days in a row?

• Have you seen a physician for the pain?• Have you had pain and or swelling in your

joints during the past year?• Have you seen a physician for the problem?

+ and - regarding each question???

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Contemporary Biomechanical Job Analysis Systems

• Physical stress checklists and surveys• Risk assessment & intervention

• Proactive (before the fact)• Save a Back program, reality overheads

• identifying at risk individuals• Tsai et al, 1992 research paper• walk through analyses

• reported/observed violations of principles• FIT & Posture• Instrument dependent vs video analysis• Quantitative vs qualitative

University of Michigan Model

Save a Back program

Save a Back claim: Worker’s Compensation $$$$

Classes held in November, 1992

Back safety training reality

Back safety training reality

Identifying at risk individuals

Tsai Abstract

Tsai et al results

Walk through survey

Job analysis form

Qualitative analysis.

• Requires a judgment of biomechanical appropriateness by the analyst as to what constitutes risk

• Based on general guidelines laid out in chapters 8-11• 8: Manual material handling (NIOSH guidelines revised in

packet)• 9: Seated work (low back anat & loading)• 10: Workplace design (shoulders)• 11: Hand tools (wrist)

• Example of Andres analysis