Tldr: It doesn’t really matter which platform as long as what you choose works for you and helps you stay consistent.
Longer answer:
You’re looking for a simple answer and this may signal that you’re looking at this the wrong way. The way you’ll improve is through consistency and as much training and intensity as your lifestyle and body can sustain.
I’ve had an improvement comparable to what you’re indicating but over multiple years. I don’t track FTP more than once a year, usually in the off season when I’m at my lowest level of fitness. I didn’t have a power meter when I started out so the improvement I can measure in watts doesn’t include the period when I probably had the most improvement.
I’ll share my current thinking based on all the mistakes ive made.
Firstly, FTP is a metric that can easily fool you. If you’re thinking about racing, race performance is the indicator. Thinking that improving 95% of 20min power is what helps you race your best in a multi sport race that lasts 4 to 17h sounds a bit unrealistic when you think about it. Besides, FTP is always estimated and can show false improvements if you apply different pacing, don’t follow the correct protocol or your equipment isn’t correctly set up (say your power meter is accidentally set to the wrong crank length. been there done that).
I would say the one thing to focus on is consistency.
You’re looking at a big improvement very quickly. That may be possible if you’re just starting out or getting back to training after a long hiatus.
If you’re starting out whatever you do will make you improve and improve fairly quickly. After that there’s decreasing returns and it’s all about consistency.
Because it may or may not be achievable, it would be better for you to set input goals that are based on your effort rather than output goals that you can’t control.
This could be as simple as defining a training plan (though a coach, a book, an online platform) or joining a club and committing to a certain number of sessions a week.
Do whatever helps you stay consistent day in and day out, week in/out, season in/out, years, etc. That means staying motivated but most of all staying healthy and not getting injured. Any injury will set you back more than having aimed too low. Over time your body can sustain more but couch to 25h a week is a sure way to get injured or sick.
You need to find what works for you for getting consistent. If accountability is what you need, find a coach or a training partner. If social interactions drive you, find a club. If you like DIY, get a plan from a book or online platform.
If I had to suggest a plan I’d say go with one from the 80/20 book.
If you need a club for the social interactions you’ll need to find one in your area. Check the website of the triathlon federation in your country for a list.
If you want a coach you’ll need to find one you click with and trust. What I look for in a coach may be different from you.
After that a good way to think about it is the following hierarchy of endurance training (adapted from Stephen Seiler):
- Consistency (most important)
- Frequency
- Volume
- Intensity
- Intensity distribution
- Periodization and tapering
- Everything else including race strategy, equipment and a million other things (least important)
There’s no point going to the next step if it impacts the step before. Also, each following step brings less fruits than the one before.
Some examples:
Training a little every day beats one or two monster sessions a week.
Training 10h every week is better than 20h one week and nothing the week after.
There’s no point planning too many sessions if your life commitments don’t allow that. You’ll feel bad about it and lose motivation. You might as well plan less and add extra easy sessions when/if you have the time.
There’s no point getting more intensity if it’s going to get you injured. If you smash yourself with too much intensity (whether that’s because you go too hard on zwift, group rides or else) you will get injured and that will set you back. This can happen as an actual injury/sickness (breaking something, stress fracture, a cold/flu, etc) or slowly creep onto you in the form of overreaching/overtraining.
There’s no point training a lot/hard if you don’t give your body time to recover, including getting enough sleep.
There’s no point signing up for a lot of back to back races because you won’t have the time to recover and train and improve. You won’t be training consistently. Racing is fun (and you can race yourself to fitness to an extent) but at some point you need to decide if you’d rather race a lot or race your best.
If you’re having an excessively long off season, it would help you find ways to stay more active instead.
About the last part of your question, “how to perform well in a race”. I’ll keep this answer shorter:
- make sure you’ve tried the pace in training in conditions as realistic as possible (such as towards the end of a longish training session)
- make sure you taper and recover into the race
- don’t test your body the day(s) before the race
- don’t try anything new on race day
- make sure your bike fits you
- train on the bike you’ll use on the race. If it’s a triathlon bike you need to be able to stay on the aerobars all the time (unless it’s not safe to do so:
i.e. twisty descent)
- have a good hydration and nutrition strategy, follow it and be able to adapt. Make sure you’ve tried it in training
- don’t swim too hard
- don’t cycle too hard
- don’t run too hard the first part of the run