noglider 

I meant to make my comment on this bike here but I accidentally put it in the "what are you wrenching on" thread.

Have you ridden a tandem? I find it quite hard. I was hoping it would improve my spouse's stamina but it didn't. However, it reduced mine, so we are more closely matched but not in the way I had hoped. Maybe one day I will get the hang of it. First there is the mental drain from the responsibility of keeping it upright. Also, because of the lower power-to-weight ratio, I am constantly rowing through the gears. Second, I have to work with my arms and shoulders. I'll be doing some upper body strengthening, so that may help.