The point is: having another fundamental class of postures available - in this case "lying" (in addition to sitting and standing) - increases our flexibility (and potential for respite) by approximately 33 percent.
For people suffering from severe RSI -- especially those for whom essentially any amount of sitting in one class (say "sitting"), even in difference positions within that class -- becomes unbearable for more than an hour or so -- then this 33 percent can be of significant impact.
Also - for some people standing just doesn't work (for more than very short intervals). So in fact the lying option provides significantly more respite potential (50 percent).
For people suffering from severe RSI -- especially those for whom essentially any amount of sitting in one class (say "sitting"), even in difference positions within that class -- becomes unbearable for more than an hour or so -- then this 33 percent can be of significant impact.
Also - for some people standing just doesn't work (for more than very short intervals). So in fact the lying option provides significantly more respite potential (50 percent).