Criteria for segment failure during workout

What is the exact criteria for segment failure? Suppose that my FTP is 150 and I have to do 100% for some time. If I do 130 will it count as success or failure? Is it a global thing or depends on the trainer? Is it just a question of average power or are there other factors that are taken into account?

For every second spent close to the target wattage, you gain “points” towards earning a full star on a section.  Average power doesn’t come into play at all.  Doing 100 watts for 30 seconds then 200 watts for 30 seconds instead of 150watts for 60 seconds won’t cut it, that would be considered a failed star.   The range of what is considered ‘close’ varies, but generally if the number isn’t glowing bright red you’re probably within the range.

Additionally the first 7-10 seconds or so of each section isn’t counted against you. That way you have to time adjust to the new power requirements and get settled in before we start taking score.

A brief, large variation from the target seems to get a half-star deduction. 

Our Zwift / Windows 10 PC / ANT+ / original KICKR combination sometimes will generate a spike in erg mode – maybe five seconds where the power requirement suddenly doubles or so while the workout should be at a steady level. It doesn’t happen most rides, and it rarely happens more than once in a ride. It did happen last ride and it got a half star deduction while the rest of the interval was spot on in erg mode.

Thanks Jon. Do you have any info regarding what is considered “bright red”? 10% 20% more?

It’s ridiculous and absurd that you can fail a segment for applying too much power.

I disagree Tim, especially for those new to training w/ power. If the goal of an interval  is to hold steady in Zone 2 or 3, and the rider is thinking “but I have so much more to give!” so they’re hitting zone 5 or 6 repeatedly? Then, they’re missing the point of the block entirely - hence the failure.  

Short spikes above or below a target caused by a change in cadence and a lag in trainer resistance adjustment in ERG mode won’t cause you to ‘fail’.   

I don’t understand how I could be applying too much power when the trainer (Wahoo Kickr) is in ERG mode. Workout interval asks me to do 4 minutes at 230w. Every time it ends and the “rest at 130w” interval comes I fail it. I don’t understand how I am failing to put out less power when Zwift is supposed to be setting the trainer. My cadence is steady but it often takes seconds before I feel the trainer change resistance after passing through the arch. My “difficulty” is set to 100% and power detection is set to “instant”.  What am I doing wrong?