In my mind, there are two kinds of workouts: Engine workouts, and Leg workouts. The engine work is LT and VO2 max stuff - the kind of work you can do back-to-back, or follow with just about any kind of workout you like. The Leg stuff is the anaerobic and neuromuscular work that leaves me fried the next day. Yesterday I did some of these - a double-clutch sprint workout. I've done almost no work at the very high end, but now that we're fully in crit season it seems about time.
I used to do my sprint work a little differently. I'd do 3 sets of 3, each starting at different speeds (17mph, 20mph, 23mph) and then jumping as hard as I could from there, for about 15 seconds. They were great for learning at what cadence I have the most accelerating power (about 120rpms) and at what cadence I'd spin out. This has helped me fine tune my sprint gear selections. I used to start in much too big a gear, never getting to the 120 rpms that kicks in the turbos.
Yesterday though I did them a little differently, with a little more specificity. I broke the sprints into three parts: Jump, follow, sprint. The first Jump is the acceleration you make to get on a wheel as it goes by before the leadout. I do these seated, ramping up to about 27mph - 30mph. Then I Follow by maintaining that speed for 5-15 seconds. Then the actual Sprint begins, where I get out of the saddle and go as hard as I can for another 15 seconds or so. The graph above shows the whole workout, and you can see the double-spikes in most (for a couple there were cars blocking my path so I couldn't do the Sprint part). Below you see a close-up of one of the efforts, with the first jump at about 1100 watts, hanging onto 500 watts for a stretch, and then the sprint at a 1000 watt spike. (The drop in power and cadence I can't explain - I think it's a data hiccup.)
You see the effort more clearly in the white/blue section, which is speed. From 15:25 - 15:30 I jump from 20 to 28mph, and I hang out there until 15:38. Then I begin my sprint, ramping up the speed again (despite what looks like 0 power and 0 cadence - maybe my powermeter maxes out at 1999 watts...)
The peak power for this workout is well below what I used to see when I would start from slower speeds and do the first (fresh) jump with everything I had, out of the saddle. It's very different to sprint from 27mph than it is from 23mph. And according to my workout file, I'm not as good at sprinting from 27mph, even though that's what I end up doing on game day. So I expect I'll do more of this workout in the future.