This will be a shameless plug for these guys, but it works. If you are limited or just want some variation in your workout in your training and have an indoor trainer, check these guys out at www.utahmountainbiking.com . I know, the trainer is as well liked as poison ivy on your arse, but it can be a valuable tool to add to your arsenal. Whoa! I didnt think it was possible to use arse and a variation of arse twice in the same sentence, how creative. Uh, ok. They have a fantastic 1 hour video designed around the trainer (yes, I actually look forward to that stupid thing now). It works. I have had it for 4 weeks and definetely had more explosive and sustainable power than before. It works on your power and strength, with intervals as well. There is a 5k time trial at the end which simulates a race environment. I can certainly vouch for it. I noticed and felt a definite improvement on my climbing and sustainable effort during the last race-which saw my max heart rate at 198 and an average of 177. Last year, I was not able to sustain that pace for that length of time. Mix it in with your training gig that you already have 2 times per week. For $14 give it a go, but you will work! Click here to get a quick sample Biking Power demo.