# How Hard is Too Hard with FTP and Zwift?



## bleckb (Jun 13, 2005)

Hi all,

We've had the winter, February in particular, from hell, so a lot of time, with some commutes on Zwift. I just completed the 8 Week Race Day Prep workout, but races are a ways off still, so I started the Build Me Up program, but the Halvfems, the first workout, crushed me. 

For background, about to turn 61. Weigh 199 and am 6'2". I logged over 5100 miles last year, did some racing where I typically got beat up, but occasionally held my own. Climbs destroyed me always. I set my FTP not from a test on Zwift on my Wahoo Snap, because I just don't test well that way, but on a 45-minute climb last summer where I averaged 232 watts over 4.2 miles at 8 percent average up about 1900 feet. Measured with a PowerTap g3. Because of this, I set my Zwift FTP at 230. 

The Halvfems efforts are at 205 watts for me, basically 90 percent. I was able to complete the first 12 minute effort at about 90 rpm and the second over/under 10 minute effort, but the third effort I failed on everyone. 

Part of this was I just didn't have a good gear to settle into, but the major part is that I just wasn't able to generate the power at the right cadence. In short, too weak I would say.

I don't mind failing on Zwift, but I don't want to be working against myself by conceivably trying too hard. 

So, the ask: would you suggest I lower the FTP so I can maintain the cadence at a somewhat, maybe 20, lower wattage, or just tough it out? I don't use ERG mode because I want to try to match cadence and power in these workouts on my own.

Thanks,


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## Wookiebiker (Sep 5, 2005)

I've found using Zwift and a smart trainer I have to drop my FTP by about 10% - 12% from my outside road FTP.

I think this stems from the constant force being applied to the pedals and never giving you a break, while outside you have changes in your power output that averages out to a specific level … Zwift, it just stays at a steady state level.

Once your pedal RPM drops below about 65 rpm, you are toast and that interval is blown as you will soon be down to 50 rpm or lower.

So, dropping your FTP from 230 to 205 would be about right from my experience. The numbers look low, but the effort is still high.


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## looigi (Nov 24, 2010)

Do one of the Zwift FTP tests? AFAIK, that's what's normally done. The 20 minute test is pretty standard. They have a new ramp test which is a bit less daunting.


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## Srode (Aug 19, 2012)

Don't use Erg mode - stay in the drivers seat going after the target wattage not a mindless machine.


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## bleckb (Jun 13, 2005)

looigi said:


> Do one of the Zwift FTP tests? AFAIK, that's what's normally done. The 20 minute test is pretty standard. They have a new ramp test which is a bit less daunting.


I've done the test, but I don't have the mental stamina to keep it up while I'm slogging away in my pain cave. That's why I went with something from an extended outdoor ride. But it was on a climb. In the end, I dropped 10 percent from that climbing FTP.

Good news is, spring has finally arrived, snow is all but gone from most roads (though not trails) so I'm going to do much more outdoor riding and much, much less indoor training. 

Thanks for the response.


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## Wookiebiker (Sep 5, 2005)

Srode said:


> Don't use Erg mode - stay in the drivers seat going after the target wattage not a mindless machine.


Well … I will say, using the ERG mode and structured intervals with Zwift can really help your FTP.

I much prefer those over races, rides or just riding in general. They make intervals much easier to complete and hit your targets.

I've tried completing regular intervals without using the customized workouts and it's just not the same. It can be good for general fitness, but not for FTP building … completing short circuits and going for "Green" jerseys however can really boost your top end sprint power, better than structured sprinting programs.


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## Srode (Aug 19, 2012)

Wookiebiker said:


> Well … I will say, using the ERG mode and structured intervals with Zwift can really help your FTP.
> 
> I much prefer those over races, rides or just riding in general. They make intervals much easier to complete and hit your targets.
> 
> I've tried completing regular intervals without using the customized workouts and it's just not the same. It can be good for general fitness, but not for FTP building … completing short circuits and going for "Green" jerseys however can really boost your top end sprint power, better than structured sprinting programs.


Generally speaking, if you aren't fading at the end of your intervals your targets aren't set right or you aren't doing enough intervals to get maximal benefit. If you fade at the end in Erg mode you won't finish, it will grind you to a stop. 

Learning to ride a zone by feel is very helpful in the real world. You should be able to maintain fairly consistent power just holding a cadence and an occasional glance at your power. I have a nice smart trainer (Elite Drivo) and quit using Erg mode about a month after starting working with a coach under his advice - much better results afterwards. I would recommend you try it for a while and see how it works for you.


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## bleckb (Jun 13, 2005)

Srode said:


> Learning to ride a zone by feel is very helpful in the real world. You should be able to maintain fairly consistent power just holding a cadence and an occasional glance at your power. I have a nice smart trainer (Elite Drivo) and quit using Erg mode about a month after starting working with a coach under his advice - much better results afterwards. I would recommend you try it for a while and see how it works for you.


I too don't use ERG mode so as to be able to keep the cranks sorta spinning once I'm fading at the end. It has helped me, over these last couple months, focus on keeping my cadence up, getting back up to power and cadence when I'm flagging near the end (or middle, or . . . ) when I just can't do that in ERG mode. My thinking is that when I"m on the road, it will be up to me to get the power and cadence going to where I want it without machine help, so I'm better off getting my legs and head in tune with that. I'm sure there's a contrary argument in favor of ERG mode, but this could be an Apple/Android or PC/MAC sorta argument.


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## aclinjury (Sep 12, 2011)

20min interval FTP is hard? 
while it could be mentally challenging at first, but it's not hard. Many serious cyclists do 20min interval as a part of their regular training block (usually 8-10 weeks long). Set a lower wattage target initially (say 90% of your FTP) for the first few times you do these intervals. Then you'll find that once you're mentally prepped, you can get into "the zone" and churn these 20min intervals out like cookies, and in 4-6 weeks you may be even going over your actual FTP, and hopefully peak by the end of your training block. Once you've peaked, you still need to do some intervals (maybe 10min) to maintain, but be realistic though, you've not going to be at the peak all the time.


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