Trace Forearm Support Through The Task
Start by watching a complete task sequence rather than asking the user to hold one pose. With armless office chairs with height-adjustable backrests, there are no chair armrests to use between typing, reading and reaching. Identify where the forearms rest during each activity and whether the working surface permits the required approach. Ask the user to describe any difficulty finding a workable position. This gives a more useful assessment than assuming that removing arms automatically resolves workstation fit, because the desk layout and the person's usual movements still shape the practical sitting arrangement.
Explore Backrest Height Deliberately
Test the backrest at several usable heights while keeping the task arrangement consistent. Ask where contact is felt and whether changing the height improves its relationship to the user's back. Check how the setting is selected and retained, then let the user repeat the process independently. Office chairs intended for shared workstations should be assessed by more than one person, since the useful position may differ. Do not infer backrest tilt or a separate lumbar adjustment from the height control. Those are distinct characteristics that require their own checks during the same comparison.

