Alan Hedge, Ph.D., is a leading expert on ergonomics and repetitive motion injuries. Since 1987, professor Hedge has served as director of the Human Factors and Ergonomics Laboratory at Cornell University (Ithaca, NY). The laboratory's research focuses on creating environmental conditions and ergonomic design criteria for healthy and productive workplaces. ASSEMBLY recently asked Dr. Hedge to share his views on industrial ergonomics.

Which assembly tasks are traditionally more prone to repetitive stress injuries?

Any task involving highly repetitive movements, especially with the hands or limbs in a deviated posture, and tasks involving the frequent application of high force, such as repetitive lifting or repetitive gripping. Don't forget about visual issues as well; we do have an aging workforce and eyestrain is a growing problem that affects the quality of assembly and inspection work.

Who's typically at more risk: assemblers who stand or assemblers who sit?

Standing requires about 20 percent more energy than sitting, so folks who stand all day will experience greater fatigue. Prolonged standing can produce circulatory problems in the legs and feet, especially standing on hard floor surfaces. Whether or not sitting is hazardous depends on how you sit. If you hunch forward it's bad; if you can relax against a slightly reclined chair back it's good, providing you have a good quality chair. The choice of posture depends on other task factors. If you have to do a lot of lifting then standing may be preferred because you can use the large muscles of the thighs to help you correctly lift objects. However, if you have to stand and stoop down to a work surface then sitting will be best. Often you can accommodate a choice in posture by using height-adjustable work surfaces.

What is the biggest mistake manufacturers make addressing ergonomics?

Ignoring the value of ergonomics! Ergonomics is the science of work and it developed as a discipline more than 50 years ago specifically to improve the performance of people at work, by boosting their productivity, safety and health. The key to good ergonomic workstation design is to have the correct tools, the correct workstations and the optimal task sequences so that people don't work in awkward postures, don't make avoidable errors and don't run unnecessary risks for being injured.

What is the best way to determine what an individual plant or department needs and doesn't need?

First, companies should look at their accident or health records to see where the greatest need is. Second, they should listen to their workers to find the most difficult jobs, and look at other indicators, such as turnover and quality control issues. Third, they should evaluate workers' posture--this can be done quickly and it gives a good indication of risks. Then they should design ergonomic interventions to minimize or eliminate the problems.

What is the best way to conduct tests and measure individual work habits?

Ergonomists have developed several quick methods for screening for the greatest risks. First, there are several posture targeting methods, such as the Rapid Upper Limb Assessment (RULA) method, or the Rapid Entire Body Assessment (REBA) method. Second, their are specific methods, such as the NIOSH Lifting equation, that can be used to estimate injury risk and guide suitable interventions.

How important is it to set up a performance profile of every assembler?

In an ideal world, everyone should have his or her own customized profile, but in reality this is seldom possible or necessary. Companies can set up profiles for different jobs; for the anthropometric extremes, such as the shortest person, the tallest person and then the average person; and for the highest risk jobs first. In this way companies can intelligently and economically improve their performance. Using a systematic method to evaluate workstations is a sensible strategy.

Which factors are the most important to evaluate?

The most important factor depends on the tasks being performed. If it's heavy lifting then force might be the most important factor. With repetitive light assembly, it's likely that posture is the most important factor. A high repetition rate can be better sustained when working in a neutral posture. Energy expenditures are lower for neutral postures.

What is the biggest mistake made with ergonomic evaluation and analysis?

Complexity often boggles evaluators! Although there are several complex ergonomic methods that can be used, mostly one can get a pretty accurate picture of the most important risk factors with quicker and simpler methods. The problems with analysis often revolve around poor advice on appropriate interventions. Seeking professional help from a trained ergonomist who keeps up to date with the latest research information or from companies that utilize the latest ergonomic principles in their designs can often speed solutions.

What is the best way to justify ergonomic investments to management?

Good ergonomics is always cost-effective. There are many, many documented case studies that confirm this. Things like workers compensation costs are really just the tip of the iceberg of inefficiency that may be present in a company. Injuries are the end result of years of working in ineffective ways, so companies are losing money from poorer performance and poorer product quality, as well as injury costs.

What is the best way to quantify results and measure return on investment?

There are many ways to quantify savings from a good ergonomics program. Decreases in injuries, absenteeism and turnover; increases in product quality and output quantity; reductions in discomfort (a precursor of injury); improvements in satisfaction and morale. Document before-and-after changes using photographs, video, interviews, survey data and postural risk analysis data, such as conducting a RULA before and after a change to show how much the injury risk has been decreased.

What is the best way to enforce an internal ergonomics standard?

Carrots always work better than sticks. I like to give workers ergonomics training coupled with correct workstation arrangement, tools and work practices. Once people begin to work in a more relaxed, neutral manner and see the productivity and health benefits, ergonomics becomes self-reinforcing. Sometimes, I encourage a "buddy system" among workers in pairs or small groups so they learn to keep an eye on each other. Frequent reinforcement or ergonomics information through newsletters or posters help to remind people of how important it is to work correctly.

Do ergonomic programs have to be expensive in order to be effective?

This is one of the biggest myths about ergonomics. In companies where ergonomic considerations did not play any role in the design of the work, the work environment conditions, the selection of the tools and the design of the workstations, and where major mistakes occurred, then there is the expense of an ergonomic retrofit. But, if ergonomics is part of the work design process up front, then there's seldom any significant additional cost because wiser choices are made about all aspects of the workplace. There may be a cost attached to doing ergonomics training, but this will more than pay for itself in the productivity benefits and injury reductions that will follow.