[notthatoldguy]

Well, I doubt that an ergonomy is the reason here. Going gym consistently benefits much more, rather than switch devices. I have never seen healthy programmers over 30 who avoided physical activity. But I saw how people from constant switching of ergonomic devices and clinics visits just in several months were able to forget about most of the pain in wrists and back just by consistent increase in their physical activity and adding some resistant training. Their back CT looks the almost same, but their lives are significantly improved. I work on any devices and sit on various chairs for almost 25 years, and never experienced any significant pains. Just visiting gym and having some massages. In my case the most significant factor that affects back health is stress, but massages is what help to maintain it.