The goal of ergonomics is to reduce the force, repetitiveness or awkwardness of activities so that the body performs tasks most efficiently and with the least amount of stress. Many excellent resources are available that describe ergonomic modifications for the office environment. Because of this information, most people now have some general knowledge of the healthiest location for the keyboard and monitor. Less commonly known is that typing style can be the cause of injuries.
In their book Repetitive Strain Injury: A Computer User’s Guide, Dr. Emil Pascarelli and Deborah Quilter describe a variety of typing techniques that can lead to painful symptoms and repetitive injuries (see book review). Even the best and most expensive ergonomic keyboard will not eliminate pain caused by the following typing methods.
Resters – Resters lean the base of the hand upon the desk or the wrist rest. This can be harmful for the following reasons: 1) It places point pressure against the carpal tunnel; 2) It isolates the small muscles of the hands and forces them to do the work of the larger shoulder and elbow muscles; and 3) It can promote wrist postures that are not neutral.
Leaners – Leaners type by placing their elbows on the desk or chair arms. This puts pressure on the ulnar nerve, the superficial nerve at the elbow.
Loungers – loungers slump in their chairs leading to compression of the spine and low back pain. Lounging also promotes forward head and rounded shoulder posture.
Clackers or Pounders – Pounders hit the keys with excessive force potentially leading to pain and tingling in the finger tips and finger joints.
Pressers – Pressers hold down keys (for example, while scrolling) with excessive force placing pressure on the small joints in the fingers.
Pointers – Pointers are hunt-and-peckers who hold their arms poised in midair. Pointers are at risk from awkward positioning if they hold their fingers stiffly rather than in a relaxed position or if the keyboard is not positioned correctly.
Thumb or Pinkie Extenders – Extenders hold one finger stiffly out while the others perform the work. This separation causes excessive strain on the tendons of the fingers.
Grippers – Grippers hold tightly to the mouse or use too much force when clicking.
The following typing tips describe work-style modifications that will help prevent injuries and maximize the benefit of that ergonomic keyboard.
- When typing, keep the fingers relaxed and slightly curled as if they are resting over a large ball.
- Tap lightly with the finger tips rather than with the pulp of the finger.
- Keep fingernails short – longer nails require that the fingers be tensely extended so that the key can be tapped with the pulp of the finger.
- Keep the thumb relaxed – not held stiffly over the space bar.
- Use the lightest touch possible on the keys.
- Don’t stretch the fingers to reach keys that are far from the home row. Move fingers closer to the key by moving the whole arm.
- Don’t stretch the fingers wide to activate a two-key command with one hand. Use one finger from each hand to activate these commands.
- Maintain a neutral wrist position.
- The mouse should be held loosely. Control of the mouse should come from the larger muscles of the elbow and shoulder, not from wrist motion.
- Don’t rest the wrist on the table or wrist rest. Use the wrist rest as a guide that the wrist slides over.
- Don’t lean on the elbow when typing, talking, contemplating, or holding the phone.
- Pad any sharp edges that the forearm rests against.
- The keyboard and mouse should be positioned so that the arms are at the sides (do not reach forward or out to the sides to activate either), shoulders relaxed, elbows opened up slightly more than 90 degrees.
Repetitive Strain Injury: A Computer User’s Guide offers more tips and exercises to help correct typing styles. Find it at Amazon.com.
Marji Hajic is an Occupational Therapist and a Certified Hand Therapist practicing in Santa Barbara, California. For more information on hand and upper extremity injuries, prevention and recovery, visit Hand Health Resources.