My goal is to increase the FTP to 280w as quickly as possible.
After the medium volume base phase of SST, FTP increased from 226w to 243w.
I’m now in week 2 of Sustained Power Build plans, medium volume.
In order to reach 280w by the end of the year, what training plan should I transition to after my sustained build is over?
This begs the question that 280 is even possible for you; it may not be, and by December that would mean a 54W gain. Unrealistic is the word that comes to mind.
What are your goals? Why is 280 your goal? Are you trying to chase the mythical 4.W/Kg? If so, why
? What is your discipline? Your goals dictate the training plan; do you have any events lined up?
I sound like Amber here (no bad thing) but you need a process goal and not an outcome goal. A watt target should be replaced with “I want to do a watt PB on date X” and then let AT sort the rest 
Assuming you did the full base, that’s 17 watts gained in 12 weeks. Nice work! Your goal is to now gain 37 watts in the next 13 weeks. There is a common misconception (I was guilty of it too) that since the next phase is called build, bigger FTP gains are in order. Unfortunately, that’s not how it works. You’ve picked a lot of the low hanging fruit, and the next 17 watts will probably be significantly more difficult than the last 17. I hope you do it, but my guess is that you will be faster and happier at the end of the year if you temper your expectation.
Thank you for your reply.
The goal of 280w by the end of the year means that I want to reach it as soon as possible.
It’s a constraint I imposed on myself when purchasing a new bike. There are no races or events to aim for at that time.
Others have pointed out that it is not realistic, so I would like to review the deadline for achieving 280w a little more slowly.
For example, do you have any advice on which plan to choose if I want to achieve it by March 2023?
That’s a good question, and I don’t know the answer. I think if you’re trying to increase your 1 hour power, then what @yajvans said, the sustained power and 40k TT could be a great way to go. But, if you’re relatively new to all of this, you might make more headway with higher intensity work. 
Additionally, if you’re using AI FTP, that number is based on your predicted ramp test score. This MIGHT be a completely different number for you, and in that case, you might do better with something like general build and rolling road race.
These questions are complex, very individual, and a bunch of unsettled science. I expect TR and their data set to have a big impact on where the consensus ultimately goes. If I were you, I’d pick whatever plans get you motivated to train consistently; that is what will primarily determine your success, IMO. For me, those are the blocks with a bit less “sustained” work.
Sounds to me you set yourself an impossible goal. Process goals are better, because they are within your control. Raising your FTP by that much may take years. (It depends on your background. If you come from some other endurance sport, you may progress more quickly.)
I’m going to come out and say it… There are no shortcuts in endurance sports. But what you can do is be smart about things.
Be consistent. Find a routine that works for you and that you can stick with, week to week and month to month. The riders that train consistently have the most consistent improvement in performance. @Nate_Pearson has mentioned this many times when they look at the TR data.
Don’t just do hard work outs. There will be diminishing returns and you will burn out. Try to mix in lots of Z2 work. This will help build a strong foundation that you can build off of month over month and year over year.
Get your nutrition dialed on and off the bike. Can’t overstate how important this is. You need to fuel the work with high quality food.
Focus on recovery. You want to get stronger? You need to recovery, both day to day with high quality sleep, but also built in recovery days/week between blocks. This is when your body gets stronger.
Try to incorporate some lifting. Lots of benefits from lifting including getting faster.
Thank you all for your pointers and advice.
I’m now in week 3 of my medium volume Sustained Power Build plans.
After finishing this build, I’m going to decide whether to go to the 40kTT specialty, the rolling road racing specialty, or repeat the sustained build again, depending on the situation, including my FTP at that time.
Of course, I’ll also review the arrival time of 280w.
That’s not a good idea. Just stick to the training plan you have picked now. There is no “bad” plan nor a magic FTP plan.
I think @Kuttermax really summarized it very well: learn to train, learn to recover and learn to eat and sleep better. Endurance sports is a long game, and gains usually take time.
Don’t review it, change your goal to e. g. adhere to a structured training plan for one season. Goals like that are toxic: even if you reach it, you’ll want more and eventually give up on the sport.
When I first started, I was at 175 ftp. The 1st 6 months ftp jumps were great. I got to 230 fairly quickly. My goal was 275 and then 300. That was 6 years ago. After 255-260, the gains were super hard to get. It took me 4 years to get to 280 but the path wasn’t linear. Usually hovering around 255 +/- 10W. When I got to 280, a week later I had Covid which took 3 weeks to get over. After Covid I went from 280 back to 245 and it’s taken me 2 years to get back to 268 now.
Just food for thought. If you want a bike, get a bike. 280w has nothing to do with you deserving a bike. Life is short. Get and ride it with a smile.
Good points above. Dial in your nutrition, work on weight loss if you want or need to. Now is the time to be working on those aspects of dialing in that ftp goal.
Also, I think you should come to terms with you might not get there and no plan from TR, FasCat etc will get you there. You can do the work or you can’t. I thought I was on the path to 5.5 w/kg but fizzled out at 5.2 and has just gone down the chute so to speak.
Best of luck and please be careful!
5.2 W/kg is amazing, and I wouldn’t say you fizzled out. Plus, you likely didn’t fizzle out, it is more likely that you have a life outside of cycling, which in many cases takes precedence.
Curious as to how old you are? This doesn’t seem right (not doubting you, but there’s more to this).
47 now
I’m a few years older than you. Big ftp jumps at this age are hard to come by. One can certainly improve but it’s just not easy.
Eh that’s not that old (I’m 45), but could be a contributor. Usually the ceiling is hard to push up, but once you do, it’s easy to get back. . I had a bad Covid setback starting 1/2020, but was able to recover my previous fitness quickly, and then some (300w pre covid, 240w post covid - 3/2022, 325w now). Good luck on your journey!
Ty. I’m a triathlete. So have to juggle running and swimming and lifting as well. But currently doing bike and lift only. Traditional high volume base has been very good to me. I just went up to 268 last week and nailing my workouts in THVB3. Feels good to be able to go 2-3 hours at 80% and not be trashed.