How was the Matias Ergo Pro recommendation reached?

You're dealing with RSI that's flagged shoulder tightening, and your physio has given you specific ergonomic requirements — that changes what matters. I evaluated the Kinesis Freestyle2 first because it's the default recommendation for most RSI cases, but when I pressed on whether its standard 9-inch separation would actually accommodate your shoulder width without forcing you into an unnatural arm posture, it became clear the Matias Ergo Pro was the better fit for your specific situation. The recommendation shifted from Freestyle2 to Matias Ergo Pro, and ChatGPT's challenges made that the right call. Your situation isn't mild RSI — it's RSI with shoulder tightening, which means you need width separation built in, not added later. The Matias arrives configured for exactly what your physio is likely asking for: shoulder-width positioning plus negative tilt, both active from day one. This recommendation was reached independently. No brand paid to appear here. The deliberation above is the complete reasoning record.

Claude vs ChatGPT: Split Keyboard for Diagnosed RSI: Which One? Join the debate.

Item: Matias Ergo Pro
Rating: 4
Author: inparticular.ai

How this recommendation was reached

iISC Trust Mark — inparticular.ai's standard for independent AI deliberation.

WHAT WAS CONSIDERED

You're dealing with RSI that's flagged shoulder tightening, and your physio has given you specific ergonomic requirements — that changes what matters. I evaluated the Kinesis Freestyle2 first because it's the default recommendation for most RSI cases, but when I pressed on whether its standard 9-inch separation would actually accommodate your shoulder width without forcing you into an unnatural arm posture, it became clear the Matias Ergo Pro was the better fit for your specific situation.

WHAT THE CHALLENGERS RAISED

ChatGPT asked the right question twice: whether the Freestyle2's maximum separation was actually enough for shoulder tightening, and then whether the Matias Ergo Pro's cable length would genuinely deliver the width you need out of the box. That pressure forced me to reconsider — the Freestyle2 tops out at 9 inches standard, which is tight if your physio has identified shoulder involvement as part of your problem. The Matias arrives ready to go to 18-20 inches with no accessories, which is materially different.

WHY THE RECOMMENDATION HELD — OR CHANGED

The recommendation shifted from Freestyle2 to Matias Ergo Pro, and ChatGPT's challenges made that the right call. Your situation isn't mild RSI — it's RSI with shoulder tightening, which means you need width separation built in, not added later. The Matias arrives configured for exactly what your physio is likely asking for: shoulder-width positioning plus negative tilt, both active from day one.

This recommendation was reached independently. No brand paid to appear here. The deliberation below is the complete reasoning record.

THE FULL DELIBERATION

They said my wrists are bent inward too much when I type — ulnar deviation I think they called it. And my arms are too close together which is tightening my shoulders. They suggested looking at split keyboards.

CLAUDE

The Kinesis Freestyle2 is where I'd start — it's the most physio-trusted split keyboard on the market, lets you set the exact separation distance your hands need, and has a low profile that keeps wrist angle neutral. For most RSI cases coming from physio referral, it hits the right balance between therapeutic benefit and not requiring a full relearning curve.

CHATGPT

What’s the maximum separation distance the Freestyle2 allows, and does that fully accommodate the shoulder-tightening issue without forcing the user to adopt an unnatural arm posture?

CLAUDE

The Freestyle2 separates up to 9 inches (23cm) with the standard cable, extendable to 20 inches with an optional longer cable. For most shoulder-width situations that's sufficient, but if the physio has flagged significant shoulder tightening, the Matias Ergo Pro goes wider and adds negative tilt out of the box — which addresses the arm posture angle more completely than the Freestyle2's optional tent kit.

CHATGPT

What’s the base separation on the Matias Ergo Pro when it arrives, and how much additional width does the split add beyond that?

CLAUDE

The Matias Ergo Pro arrives with a fixed split — the two halves connect via cable and can be positioned freely on the desk, so separation is limited only by the cable length, which allows roughly 18-20 inches between halves out of the box with no accessories needed. Combined with its built-in negative tilt and quieter Alps switches, it edges out the Freestyle2 for someone with diagnosed RSI and shoulder involvement. Final recommendation: Matias Ergo Pro. It arrives ready to address both wrist angle and shoulder width without add-on accessories, which matters when you're following specific physio guidance. The Freestyle2 is fine for mild cases — this situation calls for the Ergo Pro.

QUESTIONS ANSWERED

What’s the maximum separation distance the Freestyle2 allows, and does that fully accommodate the shoulder-tightening issue without forcing the user to adopt an unnatural arm posture?

What’s the base separation on the Matias Ergo Pro when it arrives, and how much additional width does the split add beyond that?

Claude vs ChatGPT: Split Keyboard for Diagnosed RSI: Which One? Join the debate.: Matias Ergo Pro