Bailsibub said:Hey guys,
I'm about to embark on a month's block of 2x20 training. With the way work is, I'll be doing most of the workouts on the trainer in the mornings before I head to the office.
I've never done a 20-minute interval on a trainer, preferring to keep them shorter. But after hearing so much about them on here, I'm going to try them out.
My question is, when doing 2x20s, how often do you all usually shift up or down into higher and lower gears...to simulate undulating terrain? I've never been on terrain that was an even gradient for 20 minutes, so I'm just assuming that some shifting to simulate different force requirements is something necessary.
But is my thinking off with this? Should I just put it into a gear I'm comfortable in and hold the same cadence, making sure I'm holding my L4 wattage for the duration of the interval?
This is an interesting and worthwhile question. Riding at a constant power on the trainer doesn't look much like riding on the road. Switching gears won't change your force requirement that much. If you are doing 'vanilla' constant power 2 X 20's, I would just find a gear that is comfortable and roll with it. You might find yourself shifting a bit to stay comfortable on the trainer - I shift a lot on the trainer, but I am a bit ADD.
Now the interesting part: as you have already worked out, isopower efforts don't really simulate road riding. They will work on your fitness in a very positive way, but it may be appropriate to switch things up a little. You can search the forum for 'micro-interval' to find out more. The basic idea is that, because the metabolic cost of effort accrues over a half-life of about 25-30 seconds, you can switch up the power in your interval to increase your neuromuscular cost and get a 'bonus' training adaption out of the session. As long as the rolling 30s average stays around your threshold, you should be able to complete the session. I believe Andy C refers to these intervals as "L4 with an L7 twist".
One problem with this type of workout is that, in the absence of high-tech trainers where you can preset the power to be constant, it's hard to control your power that well, so you work threshold but don't overdo it and force yourself to quit the interval early.
My approach would be to save the L4/L7 hybrids until you are pretty good at controlling your power on the trainer, but when doing your 'vanilla' intervals, don't be afraid to back off for a minute (like you are rolling into a corner or off a hill) and then sprint for a minute (like you are coming out of a corner and getting back to speed, or going up a little hill). This keeps things interesting and makes it more specific to your event.