I've been a member of the local council non-profit gym for a couple of years and used to go once or twice a week to do fixed weights, thinking I'd get all the cycle-type training I needed by road riding.
Then I read this thread -
http://www.cyclingforums.com/t-314849-15-1.htmlIt completely revolutionised my training. I now go two or three times a week and, along with the fixed weights, I now do a 1-hour session on the upright cycle trainer (with the really uncomfortable bucket saddles!),
but they measure wattage output. So I do intervals, 2 x 20 minutes, 5 x 1 minute, etc at various wattage outputs relating to my current ability.
It works. I'm 10 weeks into this and my speed and stamina have both increased significantly. I can now go up hills at a far faster pace than before and my average speed for long rides is up.
OK, it may be boring, and it certainly is hard work, but it's focused and short in length, and warm and dry in the winter, and for me it's been a revelation to get improvement in such a short period of time, and I don't expect these improvements to slow down any time soon - I'm hoping to be up to cat. 3/4 standard racing next year, and that's coming from someone who couldn't keep up on 17 mph club runs last year.
It depends what you want from cycling, but if you want to improve from your current base level fitness fairly quickly I can definitely recommend giving it a go.