Originally Posted by Mac_Biker .
. Let's say my goal is to hit 300 for 20 mins. Can I train by going at 300 watts for as long as I can, then repeating it. Then the next time, try to go even longer and longer until I can hold 300 for 20 minutes?...
That could work, but as always 'it depends'...
Can you hold the desired power (e.g. 300 watts) for at least 8 to 10 minutes? If not you're basically describing a variation on the 'pull up' approach to raising FTP where you go out and do hard efforts well above FTP in hopes of raising your sustainable power. It can work and some folks advocate this approach but IME it's not as effective or as sustainable for the long haul as a 'push up' approach where you do a lot of work at or below FTP. Folks tend to burn out quickly on too much high end work too often and that's what a pure pull up approach often leads to. It also tends to result in lower overall workloads as it's hard to rack up more than about 25 to 30 minutes of L5 time in a given workout so unless you pad it with additional L2/L3 mileage your overall workload and training base (CTL in powerspeak) tends to drop which generally isn't a good thing unless you're intentionally tapering for an important event.
If you can hold the desired power for at least 10 minutes then you could work towards 12 minute intervals at that power, then 15, etc. with all the work being performed in the higher end of the L4 range but primarily drawing on sustainable metabolic processes and focused on raising LT. That approach can work but it also runs the risk of too much mental focus during each session which can lead to troubles sustaining the program. But IMO that approach has a bit better chance of success.
Better yet is an approach that includes some Tempo/SST days, some pure long L4 days like 2x20s, 3x20s, 2x30s, 2x45s or 1x60s ridden at 90 to 95% or so of your FTP and some 'high L4' days where you target the 12 to 15 minute intervals on the high side of FTP perhaps at 97-105% of your current FTP. IOW, use a variety of intensities to work various parts of the SST/L4 range rather than always doing your focused work at the same intensity and for the same interval durations. Similarly if your events demand it then some focused L5 or L6 days might make sense as target events approach but again the trick is to use them where appropriate to your needs and blended with other intensities and durations to round out your week and to balance load management against specific intensity.
Bottom line on FTP raising, you want to figure out a program that lets you accumulate an awful lot of quality time that targets sustainable metabolic processes and sustainable power. You can try to get there with higher power for shorter durations but most folks seem to progress faster and more reliably by accumulating more time at slightly lower intensities. You still need to go plenty hard during those dedicated L4 sessions but it's generally better to rack up an hour and a half per week of solid 90-95% L4 work ridden in sustained efforts for several months or more than to get 45 minutes of 105-110% work and run out of steam on that program after a few weeks.
-Dave
