Manual Lifting:
Training Programs
in Manual Materials Handling

by Henry G. Wickes, Jr., P.E., CSP and Gary S. Nelson, Ph.D., CSP, Consultants

Links to Headings in this document.

INTRODUCTION-- Basic rules fall short of prevention.

TRAINING PROGRAM GOALS

PROGRAM CONTENT

--Warnings
--Basic biomechanics of lifting
--Basic physiology and the effects of unskilled lifting on the body
--Individual awareness of the body's strengths and weaknesses
--NIOSH Work Practices Guide for Manual Lifting
--Risk factors that increase the potential for back injury
--Handling skills
--Handling aids
--Lumbar belts
--Risk of injury associated with unskilled lifting

TEACHING METHODS

STRENGTH AND FITNESS TRAINING

BACK SCHOOLS

TRAINING VERSUS JOB DESIGN AND JOB PLACEMENT

RECOMMENDED READING

INTRODUCTION

Manual materials handling relates to the lifting, carrying, pushing, and pulling of objects. The importance of training individuals in proper manual materials handling is generally accepted as an essential element of back injury prevention programming. However, training alone has limited potential for prevention of back injuries. Training in basic lifting can only be of benefit for the handling of acceptable weights of lift. No amount of "lifting with your legs" and "keeping your back straight" can make an excessively heavy object safe to lift.

This factsheet recommends content for training programs for the manual lifting of acceptable weights. For information discussing the calculation of acceptable weights of lift, request Nelson & Associates factsheet, Manual Lifting: The NIOSH Work Practices Guide for Manual Lifting (1984).

TRAINING PROGRAM GOALS

The goals of training programs designed to promote safety in manual lifting should be (1) to make the trainee fully aware of the potential dangers associated with lifting, (2) to show trainees how to avoid unnecessary stress on the back through the use of proper lifting techniques, and (3) to make each person aware of his or her physical limits in terms of the types and maximum weights of objects he or she can handle safely.

In order for training to be effective, instructors must be well-versed in safety engineering and basic back physiology, which are central to an understanding of safe manual materials handling. The presentation of the course must also be suited to the educational background of the trainees.

PROGRAM CONTENT

Training programs should cover the following:

1. Warnings. Emphasize high risk factors of manual lifting such as weights that exceed an individual's capacity, twisting, and reaching. Stress the need to use natural lifting positions and to keep the load close to the body. Insist that workers ask for help when required by the task. Such requests should be supported by management and then followed up with job and task analysis for future guidance.

2. Basic biomechanics of lifting. Explain how the body can be represented by a system of levers or links to show how the weight of objects lifted is supported by the back.

3. Basic physiology and the effects of unskilled lifting on the body. Illustrate the basic anatomy of the spine and the muscles and joints of the trunk. Explain the injuries which are likely to result from pressure on the spinal column while lifting improperly or while lifting unacceptable weight.

4. Individual awareness of the body's strengths and weaknesses. Explain how to estimate one's comfortable and safe lifting capacity. Explain the use of the NIOSH Work Practices Guide for Manual Lifting as a primary reference. Explain the "action limit" and "maximum permissible limits" as defined in the guide.

5. Risk factors that increase the potential for back injury. Make trainees aware that individual worker characteristics such as age, sex, physical fitness, lifting experience, and level of training can affect their ability. Teach trainees to first evaluate characteristics of the material being lifted such as weight, dimensions, load distribution, and points of grasp. Highlight the effects of task characteristics (such as frequency of lift and complexity of movement while lifting or carrying) and adverse environmental conditions (such as temperature and humidity). Emphasize detrimental effects of overtime work schedules and worker fatigue on lifting ability.

6. Handling skills. Discuss body mechanics, load-moment effects, and smooth movements during lifting.

7. Handling aids. Discuss and demonstrate the use of platforms, tables, or steps that position the load or worker in the safest position for lifting. Stress the advantages of using handles or tongs that provide good grip, pads, and various dollies, hand trucks, carts, and small hoisting devices.

Lumbar belts merit special discussion. Despite long-standing use of such belts by weight lifters, thus far no studies of manual materials handlers have shown reduced injuries with commercially available weight -lifting belts. On the contrary, a recent study of over 600 baggage handlers showed a marginally significant increase in lost work day injuries for workers who discontinued wearing weight-lifting belts after a period of use (Reddell, Cheryl R., An Evaluation of a Weight-Lifting Belt and Back Injury Prevention Training Class for Fleet Service Clerks, Master's Thesis, Texas A&M University, Industrial Engineering, May 1991.).

In the absence of positive evidence of any benefit to workers, and given a finding that risk of injury actually may be increased when not wearing a belt following a period of belt use, lumbar belts cannot be recommended to aid in daily work activities involving manual materials handling.

8. Risk of injury associated with unskilled lifting. Illustrate risks with case histories from the trainee's organization and provide national or industry statistics so trainees can see the severity of the problem.

TEACHING METHODS

Trainees should receive practical training and individual instruction from the start. Pamphlets, slides or films in the classroom should provide only an introduction. Lifting technique should be demonstrated and practiced at the work site. Supervisors, as well as workers, should be involved in the training program.

1. Before scheduling classes, distribute informational materials designed to draw attention to the need to prevent lifting accidents and back injuries.

2. Start with training sessions for managers and supervisors. Arrange for the company physician to introduce the basic elements of back physiology and the causes of back pain and injury. If you do not have a company physician, consider arranging for the part-time services of a physician.

3. Have the company physician (or contract physician) and the team of trained instructors (managers and supervisors) tour the plant to inventory manual lifting tasks.

4. Class size should be controlled to allow participation of all attenders. For example, practical demonstrations at the work site should probably be limited to groups of 5 or 6 individuals.

5. Make plant tours at regular (at least monthly) intervals to observe employee lifting methods and discuss points of mutual concern.

STRENGTH AND FITNESS TRAINING

Exercises to increase strength and fitness have been part of low back pain treatment programs for many years, but only recently have strength and fitness programs been advocated in industry to reduce or prevent the onset of back pain. Several studies have indicated a positive role for strength and fitness training in reducing the onset of back pain.

BACK SCHOOLS

The "back school" is an attempt to educate the worker in all aspects of back care. The original concept of the back school was to educate patients who were already suffering (or had recently suffered) from low back pain; that is, it was a form of treatment. Studies of back schools that were part of treatment programs have generally shown that the back schools helped speed recovery and permitted earlier return to work.

A more recent use of the back school is to educate workers about preventing back pain. The preventive value of back school training is difficult to assess because of the lack of statistically valid studies that include control groups.

Back schools can be part of effective programs when implemented by employers in combination with job analysis and job design. Employer programs are even more effective when combined with programs implemented by manufacturers. Manufacturers should reduce the unit weight of products when feasible. Manufacturers must provide proper warnings and instructions for the safe handling of individual products. A significant reduction in back pain and back injury can be realized by these combined programs.

TRAINING VERSUS JOB DESIGN AND JOB PLACEMENT

Three methods are currently available to control back pain and back injury: (1) job design; (2) job placement (worker selection); and (3) training and education. Of these, job design has the greatest potential for reducing the original onset of back pain and back injury.

Job design reduces such risks through assessing the biomechanical stresses imposed on workers by specific tasks, determining the acceptability of each task, limiting excessive weights of lift through the use of mechanical handling aids, and designing work stations to eliminate unnecessary bending, twisting, and reaching movements.

Job placement, a secondary control, may be used to reduce risks where job design is limited, as in occupations with demands such as those imposed by fire fighting and emergency medical work. Such jobs require greater dependence upon pre-placement testing and selection of workers.

Workers have limited ability to overcome the risks inherent in assigned tasks. Employers must implement proper job design and job placement procedures. Manufacturers must implement proper product design including warnings and instructions to protect those handling their products from undue risks.

Training and education, the subject of this factsheet, is at best a tertiary control for reducing risks of worker injuries. Realizing this, employers must make every effort to insure effectiveness of their training by incorporating classroom and work site demonstration and practice, by monitoring progress routinely with professional staff, and by involving all levels of employees from workers to executives in their programs.

RECOMMENDED READING

National Institute for Occupational Safety and Health (NIOSH). Work Practices Guide for Manual Lifting. U.S. Department of Health and Human Services, Publication No. 81-122, March, 1981.

National Institute for Occupational Safety and Health (NIOSH). Revised NIOSH Equation for the Design and Evaluation of Manual Lifting Tasks. Ergonomics, 1993, Vol. 36, No. 7, 749-776.

Snook, Stover H., "Approaches to the Control of Back Pain in Industry," Professional Safety, August 1988.

Chaffin, Don B., and M.M. Ayoub, "Problems of Manual Materials Handling," Professional Safety, April 1976.

© Nelson & Associates, 1991, 1993.