MTB Power Conversion

[TBiking]

New to power training and putting together winter/spring training and planning to be pretty attentive to CTL, but have one issue. I am training to race MTB and keep at least one day for MTB specific training (no Power Tap). Does anyone have a rough estimate of TSS ( or any way of determining) per hour? I realize effort is the key so lets say pretty solid effort which if I had to guess in an effort to convert to road watts ( and this is a very rough estimate ) I would say around 200 - 220 watts for endurance pace and I will be putting in some harder efforts which might eguate to 300 for 20 min intervals. I also realize that the effort will be much more up and down then on the road and will effect other numbers.

Thoughts?

 

[Woofer]

It depends on the terrain you train on and the length and intensity of the ride...
Most of my MTB rides with a PowerTap are much easier as measured by TSS and AP and NP versus any road ride, however the perceived exertion is much higher.

 

[jbvcoaching]

Estimate IF, and you can measure duration.

TSS = IF^2 * duration (in hours) *100

When I first got cyclingpeaks, I'd play 'guess the IF' before every download. PE being pretty reliable and all, I was (and still am) usually within a couple hundredths.

 

[strader]

Here's how I do it: For typical mtb racing and race pace rides I figure low end of L4 for power (91% ftp). For fast training rides I figure low end of L3 (76% ftp). For easy mtb rides like with a group of slower riders with lots of short breaks and easy spinning I use low end of L2 for power (56% ftp). For something really intense like a 30 minute short track race use 100% of FTP.
So TSS would work out like this:
Short track race: 100 TSS/hour
mtb race: 83 TSS/hour
solo training ride, endurance pace: 58 TSS/hour
Group ride with slower riders and lots of stops: 32 TSS/hour

 

[TBiking]

It depends on the terrain you train on and the length and intensity of the ride...
Most of my MTB rides with a PowerTap are much easier as measured by TSS and AP and NP versus any road ride, however the perceived exertion is much higher.

Woofer - interesting statement and something I was wondering about. I limit my MTB training as I never seem to get the conditioning benifit when I do 2/3 days on MTB bike even though my technical skills improve.

Others - thanks for good feedback, it is the intensity factor issue that I struggle with as the percieved effort is higher. Anyone have thoughts on NP effect?