Injuries and Illness

Lean Manufacturing: When More Efficiency Leads to Aching Backs

“Don’t let your lean manufacturing become anorexic,” says Certified Professional Ergonomist Chris Shulenberger, M.S. Engr., and Technical Director for Ergonomics with Bureau Veritas North America. If you do, you’ll pay the price.

Over the last decade, many manufacturers have embraced “lean manufacturing,” a strategy to eliminate wasted time, motion, and storage by streamlining production, altering production processes, and paring back warehousing. These changes often show up in the bottom line at first as solid black, but they may have long-term repercussions for your workforce that can put you right back in the red.

Short-Term Gain, Long-Term Cost?

“Approximately 65 percent of all workers’ compensation claims are for musculoskeletal disorders,” says Shulenberger. These injuries include sprains and strains, overexertion injuries, and cumulative trauma. But many employers may not make the connection between high musculoskeletal disorder (MSD) rates among their employees and their lean manufacturing initiatives.

“When you increase short-term efficiencies, you have unintended consequences,” Shulenberger notes. For example, if your just-in-time system for delivery fails—because, for example, an important shipment was delayed by the summer’s Midwestern flooding—your production may languish. When the raw materials finally arrive, you have a backlog of orders to fill. For workers that backlog means more overtime and an increased risk for back injuries and other soft tissue aches and pains.

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Risk Factors and Pitfalls

Lean manufacturing can work well and benefit the bottom line, but only if you take concrete steps to identify and address its risks. If you streamline your processes, watch out for these potential pitfalls that could turn “leaner” into just plain “meaner”

  • Overtime. Just-in-time or lean manufacturing depends on a smooth supply chain, and when there are glitches, workers have to pick up the slack with increased production and longer hours. Both of these factors can contribute to MSDs.
  • Hyperefficiency. Lean manufacturing strongly emphasizes eliminating waste. For some employers, this drive to improve employee efficiency and productivity ignores human limitations. If you remove all the waste from a person’s job, you risk eliminating invisible but necessary recovery time—time that workers’ bodies need to restore energy to cells and prevent disabling MSDs.
  • Job decision latitude. A worker’s lack of control over the moment-to-moment decisions about his or her own job tasks is a documented risk factor for MSDs. When you increase work intensity, a side effect is the decrease in a worker’s authority to decide how to proceed with a task or allocate his or her own time.

Reducing Risk

Is it possible to use lean strategies without putting your workforce at risk and incurring tens of thousands of dollars in workers’ comp costs because of ergonomic injuries? Studies of lean manufacturing facilities have suggested that employers need to pay special attention to:

  • Ergonomic risk factors and the pace of work. If you speed up the work pace without first addressing ergonomic risk factors, you’ve created a recipe for MSDs.

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  • Workers in pain. Sometimes supervisors in lean manufacturing facilities have been slow to respond to worker reports of increased levels of fatigue, intermittent discomfort, and/or pain—the earliest symptoms of an MSD. In other cases, a “working through pain” culture has been established in which employees were encouraged, like high-performing athletes, to ignore early symptoms. However, unlike professional athletes who see trainers for a thorough assessment after the game, these workers shouldn’t be expected to work through the pain for a shift. Pain that is “worked through” for days or weeks on end may become the next disabling MSD. Make sure workers know to report any MSD symptoms and supervisors know how to respond appropriately to these complaints.
  • Management of change. During the changeover to a lean manufacturing process, some workers report increased decision-making latitude and job satisfaction, but this dissipates after a few years when new work procedures become routine and no more decisions remain to be made about improvements. Meanwhile, injuries rise in the wake of a changeover because of increased production, reduced job rotation, and other factors but then level off or decrease over time. Pay attention to risk factors during changeovers and be sure to benchmark injury rates so you’ll know if something has gone wrong.

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