One of the products/services I love and find indispensable in my training is TrainerRoad. It provides literally hundreds of structured indoor training workouts that are to be performed on your indoor trainer. It also gives several multi-week training plans that utilize these workouts to help you improve toward your specific goal. What TrainerRoad has, though, that makes it absolutely killer is Virtual Power:
TrainerRoad uses an ANT+ USB stick to talk to your bike’s Speed/Cadence and uses the known power curve of your trainer (i.e. Cycleops or Kirk Kinetic) to give you what they call “Virtual Power”. This provides extremely reliable data that you can use to measure your progress and ensure that you are working hard enough when you’re supposed to to be kicking ass, and easy enough when you’re supposed to be resting.
A quick note about accuracy. The most common question I see about TrainerRoad’s Virtual Power data is always “how accurate is it?”, and the answer is very simple. It isn’t. Virtual Power is not ACCURATE. That is, it will not reliably give you the actual power you are putting out. I need to be very clear here, though. The fact that it is not accurate should not imply that it is not useful. Power data does not need to be accurate to be useful, it only needs to be consistent and reliable. Virtual Power is both of these things. All of this is to say that while Virtual Power does not translate directly to power that you will put out on the road and you should absolutely not brag to your power meter owning friends about your 300+ FTP, it will help you become a better/stronger cyclist.
If you happen to have a power meter, you will use this instead of virtual power as it is more accurate and will translate directly to the road when you get off the trainer. I personally started with Virtual Power and found the power data so useful that I invested in a power meter.
Here is a very quick video that walks through the software. I would encourage anyone serious about improving their fitness on the bike to check it out. TrainerRoad.com