emmi maybe check out
http://www.abcc.co.uk/Articles/turbotrn1.html
i'm recovering an ankle sprain - I haven't got a bike that will go on a turbo trainer but i recently went to a spinning class - i know you don't have time to do that regularly but if you can get to one or two they might give you some practical ideas.
that said - i've only been to one spinning class - as a non-proper cyclist (commute about 7 miles a day - no computer etc) i was slightly confused.
The session i went to - i was more limited by leg pain (lactate build up?) than aerobic capability (so although i was panting and sweating it wasn't the limiting factor).
This session seemed to do a lot of standing up in high gear (where i couldn't pedal very fast). This goes against the recommendations in this thread for high cadence. If I go to spinning again should I try do lower resistance higher cadence (the resistance setting in these things is up to the individual - allowing for mixed ability class).
If i do the high resistance/low cadence will i get massive thighs??