Warehouse Ergonomics: The Strike ZoneMarch 25, 2020
“Guessing what the pitcher is going to throw is 80% of being a successful hitter. The other 20% is just execution.” -Hank Aaron
In What Is the 80/20 Inventory Rule, we looked at how prioritizing the top 20 percent of products that generate 80 percent of your sales can greatly improve your fulfillment efficiencies. The 80/20 rule, also known as the Pareto Principle, states that 80 percent of consequences come from 20 percent of the causes. That principle, in theory, could be applied to just about anything—including warehouse ergonomics.
Every warehouse, for example, has products (their 20 percent) that move faster and at a higher volume than others. What if those items were moved to an area to make retrieving them easier, faster and safer for workers? That space is called the strike zone, and it should matter to warehouse operators. Here’s why:
According to a 2018 Workplace Safety Index study compiled by insurer Liberty Mutual’s Research Institute, serious, nonfatal workplace injuries amounted to nearly $60 billion in direct U.S. workers compensation costs. The top cause was overexertion, which includes injuries related to lifting, pushing, pulling, holding, carrying or throwing objects.
The Occupational Safety and Health Administration (OSHA) reports that more than 145,000 people work in over 7,000 warehouses across the United States. It’s no wonder warehouse operations can be hazardous for workers and costly for businesses. In fact, overexertion cost businesses $13.67 billion that year alone.
But there are things that can be done to minimize overexertion injuries in warehouses and distribution centers. One of them is adapting the strike zone.
What Is the Strike Zone?
In a person, the strike zone is between knuckle and shoulder height. This area has been identified by ergonomists as the optimal zone for lifting, handling and carrying material because workers can move their hands freely without too much reach or bend. As a result, handling items in the strike zone reduces risks of lower back and shoulder injuries.
Applying the Strike Zone
To put the strike zone into effect, you need to first identify the products that move the fastest and at a higher volume—your top 20 percent. Then you’ll want to strategically place any of that manually-handled inventory within the strike zone to reduce reaches and lifts by workers.
It’s likely not everything will conveniently fit within the strike zone, so you may need to modify this strategy to make best use of your storage space. You could place heavier, high-volume items in the strike zone but store lighter, low-volume ones just outside of the zone, for example.
Generally, you want to keep:
- High-volume items low in the strike zone and close to the front-end of the system to minimize travel.
- High-moving inventory low to lessen ladder climbs and potential falls.
Warehouses with dynamic storage and retrieval systems, meanwhile, can use vertical and horizontal carousels or vertical lift modules to deliver goods to workers within the strike zone.
Applying the strike zone can help improve the safety and efficiency of your warehouse ergonomically. It successfully minimizes bending and reaching to reduce the risk of back and shoulder injuries for workers, all while increasing productivity.