As a touch typist (120-140wpm) that types entirely with muscle memory I notice that sometimes I use my left hand to type a key on the right and my right hand to

As a touch typist (120-140wpm) that types entirely with muscle memory I notice that sometimes I use my left hand to type a key on the right and my right hand to type a key on the left. It really just depends on what finger is closest compared to the last key that I hit with that finger. Unfortunately this keyboard would mess me up in that regard when I try to click r,t,g,f,v,b with my left index finger or y,h,n,m,j,u with my right index finger. Just curious, but is muscle tension always a bad thing? Wouldn't that just exercise your muscles and make them more durable to do the same actions again? I'm sure after 20 years of typing these muscles are probably resistant to this kind of activity.