Applying Ergonomic Reach Zones to Your Workspace

Anthropometry is the study of the sizes and proportions of the human body. The data collected in this field is used in the manufacturing and design of ergonomic tools and equipment.

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One of the most common applications of anthropometric data is the determination of where to place items in the workspace. Proper placement in an area called the neutral reach zone can reduce the risk of musculoskeletal injuries and improve user efficiency.

What are reach zones?

A workspace can be characterized by four horizontal and three vertical reach zones.

The primary zone (Zone 1) is often called the neutral reach zone or the optimal reach zone. The horizontal neutral reach zone is defined as the area that is easily reached with a sweep of the forearm across the workspace. Working in this area allows you to keep your elbows relatively close to your body with your shoulders relaxed. You should be able to use these items by extending your arm. Little to no reach should be required to use items in this region.

The vertical neutral reach zone describes the area 5"-8" above and below the level of the appropriate desk height. Frequently used items, such as a keyboard and mouse, should be in this area because it is the most convenient and requires the least body movement. Most of your work should be done in horizontal and vertical Zone 1.

The Secondary Zone (Zone 2) is the area that you can reach with your arm stretched out away from your body. Horizontal Zone 2 is slightly beyond arm’s length. You should put items that you use less frequently or for shorter durations throughout the day in this area. This may include notebooks, binders, or reference material. The middle of Vertical Zone 2 is shoulder height when the arm is extended straight out. Vertical Zone 2 includes the space 8"-12" above and below your shoulder height.

The Tertiary Zone (Zone 3) is the area you can reach with the arm stretched out from the body while bending at the waist and leaning your trunk forward. It is slightly beyond arm’s length so it is appropriate for infrequently used items or tools, but you should generally avoid working this area. Zone 3 is sometimes referred to as the Extended Reach or Outer Reach zone. Horizontal Zone 3 is 30" — 44" away from your body when reaching horizontally across the work surface. Vertical Zone 3 is also called Maximum Reach and covers the area greater than 12" above shoulder height.

Zone 4 only applies to the horizontal plane and should be used mainly for storage. It is the area greater than 44" away from your body. Most office workstations are less than 44" deep, however, industrial settings or collaborative workspaces might have a Zone 4.

Ergonomic Reach Zones

Horizontal Reach Zones

• Zone 1 — Primary (Neutral/Optimal): 15” — 17”
• Zone 2 — Secondary: 17”- 30”
• Zone 3 — Tertiary (Extended/Outer): 30” — 44”
• Zone 4 — Maximum Reach: >44”

Vertical Reach Zones

• Zone 1 — Primary (Neutral/Optimal): 10” — 16” (5”-8” above & below neutral)
• Zone 2 — Secondary: 16”- 24” (8”-12” above & below shoulder height)
• Zone 3 — Tertiary (Maximum): >24” (more than 12” above shoulder height)

Note: The guidelines above apply to the majority of workers, but people who are shorter or taller than average may need to adjust these dimensions.

The Neutral Reach Zone

The neutral reach zone is the area that you can comfortably reach while maintaining a neutral posture. Neutral postures are positions that promote proper alignment of your body and allow you to sit or stand for extended periods of time.

In sitting, your feet are flat on the floor with your hips and knees bent to 90 degrees. The back of the chair should support the natural curve of your back. The shoulders are relaxed with the arms resting naturally at your sides. Your forearms should be parallel to the floor with the wrists in a neutral position (not extended up or flexed down).

To achieve neutral posture in standing, place both feet on the floor with your knees unlocked. Your arms should rest comfortably at your sides as in the sitting position. The elbows are bent approximately 90 degrees with your forearms parallel to the floor. Your wrists should also be in the neutral position.

The Impact of the Neutral Reach Zone

A study published in the International Journal of Occupational Safety and Ergonomics examined the effects of neutral posture in sitting on muscle tension during computer use. The study used surface electromyography (sEMG) to measure muscle activity in four positions.

The researchers confirmed that working position has a significant influence on muscle tension in an office environment. The data showed that keyboard placement was the most important positional factor and muscle tension decreased immediately when subjects were placed in the proper position.

To maximize the benefit of the neutral reach zone:

• Keep frequently used items such as your keyboard and mouse in Zone 1.
• Place notebooks, binders, and documents that you refer to often in Zone 2.
• Use Zone 3 for anything that isn’t used several times per day, or at least daily.
• Zone 4 is for storage in larger workspaces greater than 44" deep.

If you need to store items under your work surface, make sure that they don’t limit the adjustability of the work surface or interfere with leg clearance.

Working in the neutral reach zone promotes a neutral posture that reduces strain on your back, neck, and shoulders. It is the best way to prevent repetitive strain and musculoskeletal disorders while allowing you to work more efficiently.

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