When are Wrist Rests Good—What About Palm Rests?

by Ian Chong, CPE

Palm rests are an alternative to wrist rests and are generally beneficial when wrist tendonitis structures are inflamed and/or sensitive to tactile stimulation.

The palmar area of the hand is usually less damaged by occupational tasks and also usually less impacted by repetitive motion tasks. However, sensitivity must be observed when applying palm rests, which should not be viewed as a total corrective alternative for everyone exhibiting wrist/hand discomfort. For instance, computer users who develop symptomology exhibiting palmar and wrist areas as tremendously sensitive to any type of outside stimulation (especially surface pressure), would require additional aid in supporting upper extremities.

As consultants, we use wrist rests only after a significant ergonomics analysis has been performed. We have noted instances of wrist rests/supports being applied "across the board" which is not only ineffective, but often the cause of further problems.

Our practical experience indicates the wrist support (when properly applied/specified) is a necessary and functional workstation component. However, it must be applied in view of full hand, wrist, arm aggregate and task performance analysis. Simply placing a piece of ergonomic labeled rubber under painful wrists will do no good, and may make the problem worse. Even with a good wrist rest/support improper hand/wrist placement may still result in further/rapid biomechanical breakdown due to continuous compression of internal/neural wrist structures.

The onset of wrist pain is not the only time one should think of proper application of wrist rests/supports. The posture of simply holding hands over the keyboard without any support other than at the shoulder causes a great deal of strain in upper extremity musculature, eventually evolving to (static) fatigue, discomfort and pain in all areas of the upper extremities. Properly applied, wrist rests/supports can help offload this type of detrimental static activity.

Forearm, upper arm and even shoulder discomfort/injury can benefit from the proper application and specification. Use of a rest/support should be applied with the overall goal of allowing repetitive motion musculature recovery (i.e. wrist extensor musculature), while neurological/tendonitis structure strain is reduced during posture correction.

We have found the key to biomechanical relief is effective keyboard orientation with a wide range of adjustability offered by a good wrist rest/support. The equipment must have the ability to conform to individual biomechanical conditions and anatomical dimensions.

An example of a good and successful wrist support system, is the Adjustmate by ErgoDesign which offers adjustable height, adjustable angulation (positive and negative) and controllable contact surface for wrist support. The Adjustmate system also offers negative tilt capability for the keyboard when installed as an under desk unit. It also offers two sizes with left or right side mouse/trackball/notepad area. A lateral slide feature enables installation within cramped desk configurations, and the entire Adjsutmate system can be either stand alone or attached to existing under desk keyboard units.

The Adjustmate system's flexibility allows us to customize and place appropriate biomechanical support exactly where it is needed.

We have found a good palm rest system in the DynaRest system which uses a polished stainless steel plate between the keyboard and keyboarder. The base of the hands rest on two individual contoured free sliding (on aircraft grade teflon) palm rests. This enables the user to effectively move (slide—like an ice skater over the steel plate) hands to any keyboard position with continuous support, thereby offloading significant musculature activity, as well as encouraging good wrist posture.

We have even used arm supports manufactured by LMB Hand Rehab Products Inc. which offer support for the forearm without sensory impact at the palmar hand or wrist structure. Named the Desk-Rest, it cantilevers two custom shaped supports like diving boards out from the desk along side the torso and under the arms. The supports are adjustable in spacing width as well as angulation. The Desk Rest offers more control for precise forearm support if contact at the wrist or palm areas is not an option. Like the Adjustmate and DynaRest systems, the Desk Rest also allows proper positioning of the entire arm aggregate resulting in benefits in the shoulder musculature.

As we apply any type of hand/wrist/arm support is always important to determine exactly what the anatomical issue is and where it is. This step is paramount in determining the most appropriate equipment. The difficulty with wrist rest/support applications today is that they are often not appropriately specified or customized to the individual worker—rendering them about as ergonomically beneficial as an ordinary pillow.

Ian Chong, CPE is Principal of Ergonomics Inc. in Seattle WA. USA. The firm has over 20 years of experiences providing ergonomic solutions to both public and private sector companies. For more information please contact:

©Copyright Ergonomics Inc. 2000. All rights reserved worldwide.