Best Split Keyboards for Wrist Posture: What the Ulnar Deviation Studies Measured

Put both hands on an ordinary keyboard and look at the line from your elbow to your knuckles. The home row is about as wide as your two hands side by side, and your shoulders are a good deal wider than that. To close the gap, each wrist bends outward toward the little finger. That sideways bend is called ulnar deviation, and on a flat, one-piece keyboard you hold it for every word you type.

A split keyboard breaks the key bed into two halves and angles or separates them, so the hands meet the keys without the wrists folding outward. It is aimed at that sideways bend, and at little else.

What a conventional keyboard does to the wrist

The best summary of the posture data is a review by Marklin and Simoneau, published in the Journal of Orthopaedic and Sports Physical Therapy in 2004. Across the experimental studies on touch typists, a conventional keyboard put the wrists in 10 to 15 degrees of ulnar deviation and about 20 degrees of extension, with the forearms turned nearly fully palm-down.

OSHA's Computer Workstations eTool says a traditional keyboard may cause you to bend your wrists sideways, and recommends considering alternative keyboards to promote neutral wrist postures.

What splitting the keyboard changed

One of the larger posture studies is Marklin, Simoneau and Monroe in Human Factors, 1999. Ninety experienced office workers typed on commercially available split keyboards, both fixed-angle and adjustable, and on a conventional board. When the split keyboards were set up correctly, mean ulnar deviation of both wrists fell from 12 degrees to within 5 degrees of neutral.

A 2001 follow-up by Marklin and Simoneau in Physical Therapy tested how far apart the halves should go. Eleven typists used halves 20 cm apart, half a shoulder width apart and a full shoulder width apart. All three reduced ulnar deviation, with no difference among them. A modest separation did the job.

In a 2007 study in Applied Ergonomics, David Rempel's group tracked 100 people typing on six keyboard configurations. An opening angle of 12 degrees, a gable of 14 degrees and a flat slope gave the most neutral posture overall, and participants liked a conventional laptop keyboard least.

A 2009 follow-up in Ergonomics tested 24 touch typists on seven settings of a split keyboard. An opening angle around 15 degrees balanced less ulnar deviation against added forearm rotation, slopes between 0 and minus 4 degrees produced the least wrist extension, and the lower keyboard height reduced shoulder elevation and wrist deviation together.

On speed, the 2004 review found experienced touch typists adapted within about 10 minutes at roughly their usual speed and accuracy.

What the trials found about pain

Posture is the mechanism. Symptoms need a trial, and the key one is Tittiranonda and colleagues, in the American Journal of Industrial Medicine in 1999. Eighty computer users who already had upper limb musculoskeletal disorders were randomised to one of three alternative-geometry keyboards or a placebo keyboard for six months. The Microsoft Natural Keyboard group, and to a lesser extent the Apple Adjustable Keyboard group, showed an improving trend in pain severity and hand function compared with placebo. There was no consistent improvement in clinical examination findings. Greater satisfaction with a keyboard correlated with greater improvement in pain.

That is encouraging, and the 2004 review was clear that it falls short of proof.

One caution for carpal tunnel. In a 2008 study, Rempel, Keir and Bach measured carpal tunnel pressure in 20 people while they typed. Wrist extension and radial deviation, the bend toward the thumb, raised it. Ulnar deviation, the bend a split keyboard reduces, was not the direction linked to higher pressure. For that diagnosis, the extension angle and a clinician's advice matter more.

Three checks before you buy

Check the number pad. A full-size board with a number pad pushes the mouse further out to the right. If one shoulder aches rather than both wrists, where the mouse sits relative to the keyboard is the bigger problem, and a board without a number pad helps it.

Check the slope. OSHA says not to use keyboard feet if they increase bending of the wrist. The 2009 study favoured a slope between flat and minus 4 degrees. A keyboard that only tilts upward at the back works against the split.

Check whether you touch type. The 10-minute adaptation figure comes from touch typists. If you look at the keys, expect longer.

All four keyboards below were checked as live Amazon listings with a price on 2026-10-02, and each was at or below the manufacturer's own list price.

Logitech ERGO K860

Wrong for you if one shoulder aches from reaching for the mouse, because this is a full-size board with a number pad, 456 mm wide, and that width pushes the mouse further out.

For most people who want one box with nothing to set up, this is the pick.

Kinesis Freestyle2 for PC, 9-inch separation

Wrong for you if you want the keyboard to slope away from you or support your palms out of the box, because both the tenting kit and the palm supports are separate purchases.

If you want to tune the geometry rather than accept a fixed one, start here.

Kinesis Freestyle2 Blue for PC

Wrong for you if you work mainly on a Mac, because Kinesis lists Mac support for this PC model as basic functionality with no hot keys.

If you liked the wired Freestyle2 but want it wireless, this is the same keyboard without the cord.

Perixx PERIBOARD-512

Wrong for you if you need wireless, or a narrow keyboard, because this one is wired and 485 mm wide with a number pad.

Keyboard	Split	Number pad	Palm rest	Connection	Price
Logitech ERGO K860	Fixed, curved	Yes	Built in	Bluetooth or receiver	$149.99
Kinesis Freestyle2	Adjustable, 9 in	No	Optional	Wired	$94.00
Kinesis Freestyle2 Blue	Adjustable, 9 in	No	Optional	Bluetooth	$110.00
Perixx PERIBOARD-512	Fixed	Yes	Built in	Wired	$49.99

Which one

One piece, negative tilt, nothing to set up: the Logitech ERGO K860.

Your own split angle, and the mouse kept close: the Kinesis Freestyle2.

The same, without a cable: the Freestyle2 Blue.

Not sure the split will suit you: the Perixx.

What a split keyboard will not fix

If your elbows sit below the desk surface, a better keyboard on the same desk keeps the same problem. A keyboard tray that lowers the keyboard and mouse together addresses the height, and the full order of operations, desk height first and then screen and hands, is in the ergonomic desk setup guide. If the mouse forearm aches, a vertical mouse addresses that forearm's rotation.

And the palm rest that comes with the K860 and the Perixx is a separate question with separate evidence, much of it less encouraging than the product listings suggest. Rest the heel of the hand in the pauses, not while the fingers are reaching for keys.

Questions people actually ask

Does a split keyboard help wrist pain?

It reduces the outward bend of the wrist. In a study of 90 office workers, correctly set up split keyboards cut ulnar deviation from 12 degrees to within 5 degrees of neutral. A six-month trial found an improving trend in pain, but no consistent change in clinical findings.

Does a split keyboard help carpal tunnel syndrome?

There is no good evidence that it treats it. The carpal tunnel pressure study by Rempel and colleagues found that wrist extension and bending toward the thumb raised the pressure, not the outward bend a split keyboard corrects. A clinician is the right person to ask about a diagnosis.

How far apart should the halves of a split keyboard be?

Not as far as you might think. In the 2001 Marklin study, halves 20 cm apart, half a shoulder width apart and a full shoulder width apart all reduced ulnar deviation, with no difference among them. For an angled split, studies point to an opening angle of roughly 12 to 15 degrees.

Sources

• Marklin RW, Simoneau GG. Design features of alternative computer keyboards: a review of experimental data. Journal of Orthopaedic and Sports Physical Therapy, 2004, 34(10), 638-649, for the conventional keyboard angles, the effective slant and separation ranges, the slope and tenting findings, adaptation time and the call for trials.
• Marklin RW, Simoneau GG, Monroe JF. Wrist and forearm posture from typing on split and vertically inclined computer keyboards. Human Factors, 1999, 41(4), 559-569, for the 90-worker study and the 12 degree to within 5 degree result.
• Marklin RW, Simoneau GG. Effect of setup configurations of split computer keyboards on wrist angle. Physical Therapy, 2001, 81(4), 1038-1048, for the three separation distances.
• Rempel D, Barr A, Brafman D, Young E. The effect of six keyboard designs on wrist and forearm postures. Applied Ergonomics, 2007, 38(3), 293-298, for the 12 degree opening, 14 degree gable and flat slope result.
• Rempel D, Nathan-Roberts D, Chen BY, Odell D. The effects of split keyboard geometry on upper body postures. Ergonomics, 2009, 52(1), 104-111, for keyboard height, slope and opening angle.
• Tittiranonda P, Rempel D, Armstrong T, Burastero S. Effect of four computer keyboards in computer users with upper extremity musculoskeletal disorders. American Journal of Industrial Medicine, 1999, 35(6), 647-661, for the six-month randomised trial.
• Rempel DM, Keir PJ, Bach JM. Effect of wrist posture on carpal tunnel pressure while typing. Journal of Orthopaedic Research, 2008, 26(9), 1269-1273, for the carpal tunnel pressure findings.
• OSHA Computer Workstations eTool, Keyboards, for the sideways bending, alternative keyboard and keyboard feet guidance.
• Logitech ERGO K860, for the tilt angles, palm rest claim and list price.
• Logitech ERGO K860 for Business data sheet, for the K860's dimensions, weight, keys, battery, Easy-Switch and warranty.
• Kinesis Freestyle2 for PC, for the separation, slope, key switch, cable, weight, warranty, tenting options and list price.
• Kinesis Freestyle2 Blue for PC, for the Bluetooth, battery, key switch, Mac support and list price.
• Perixx PERIBOARD-512, for the dimensions, weight, cable, palm rest and price.