I've seen in a few places Shai recommending to use the left thumb to hit the spacebar if the right hand is feeling tired or strained. I have tried this a few times, most recently tonight on my laptop, and I can't get used to it at all. It really freaks me out in fact. It must be a left/right brain thing that leaves me feeling a bit disoriented.
I've found that the only time I feel strained is when using a laptop, as my left thumb hovers above the keyboard. On a normal desktop keyboard my left thumb rests on the edge of the 'board below the spacebar quite happily.
Has anyone else had this? Maybe it's just me as I rarely use my laptop now.
"It is an undoubted truth, that the less one has to do, the less time one finds to do it in." - Earl of Chesterfield