I don’t see what 102 does for me. It’s much more taxing for very little extra improvement, as opposed to doing way more work at 98%. What physiological adaptations are caused by 102% that are demonstrably better than what happens at 98-100%?
I ask, because I stopped doing 102%, and look for a level equivalent below 100. Just wondering what I am missing out on.
These workouts are designed to increase the work (Kj’s) you can do above FTP. Training Peaks calls it Functional Reserve Capacity (FRC) or how many Kj’s can you sustain continuously above FTP. As an example, having a 350 W FTP with 15Kj FRC is probably worse than a 330 FTP with 30Kj FRC. I just picked numbers but, the 330W rider can probably respond to surges longer/better than the 350W rider…
Right at the threshold, you behave very differently slightly below, right at and slightly above threshold. For that reason, a workout at 98 % is much easier than a workout that has you at 102 %, much easier than the relatively small difference in watts suggest.
Since you are right at threshold, you are forgoing a lot of adaptations if you do not cross threshold, but stay at or below it.
In addition to what @KorbenDallas writes, there are a number of other benefits:
I think these are also meant so that you can progress without retesting of account for people that undertest
Make you more tired and do not allow you to do proper amount of threshold. My personal opinion is that doing thr work just below but prioritise TiZ is way better approach. If you want work above, do this by O/U and vo2 max workouts. TR loves suprathreshold workouts and ditching them completely was my best move. Of course if you are TTer they are part of specificity then you can sprinkle them closer to your race.
Even as a TT er I find workouts like Kaweah and Mount Baldy much more useful than Tweed 10mins@ 96-99 is better than 5@102. That said I race 25/50 more than a 10…mind you by the time I get to this type of stuff I tend to do them outside on the road.
From WKO:
To answer that question, let’s start with Anaerobic Capacity. Anaerobic Capacity can be defined as the maximal work performed during maximum-intensity, short-term (typically 30-90 seconds) physical effort, and it reflects the energy output capacity of anaerobic glycolysis. Simply put, it is the output of your anaerobic (without oxygen) energy system. The challenge of Anaerobic Capacity is that it can be difficult to measure and track, so we needed a more functional solution. Enter Functional Reserve Capacity.
Using the Power-Duration Model in WKO, we now have the ability to quantify your anaerobic capacity as Functional Reserve Capacity (FRC). FRC is similar to anaerobic capacity, only more functional, because it takes into account the small amount your aerobic system contributes (you are still breathing in those hard efforts, after all) to your total power output. Your FRC is basically the total amount of work that can be done during continuous exercise above your Functional Threshold Power (FTP) before fatigue occurs.
In other words, your FRC is your anaerobic battery. Once you go over threshold, you start draining that battery, and it can’t be recharged until your effort goes below threshold again. The further you go over FTP, the faster that battery drains. Both genetics and training affect the size of your battery, and understanding how training increases or decreases the size of your battery (as reflected in your FRC score) will help you improve your training efficacy and performance.
If we’re talking about building anaerobic capacity, this looks like a more direct approach:
If you want to work just above threshold I think the best way to do that is over unders. 110/90 or 115/90. Maybe with a 2 minute hard start first.
I would argue that 102% is still mostly below Cp and not a big stressor of FRC. Wko seems to be in the Cp=ftp camp but riding at Cp is no longer a steady state.
105%… now we’re talking.
I would say that a workout at 102% only matters for those who only ride workouts on their trainer at 102%.
First, most people don’t know what their exact FTP is down to the watt. Second, even if you knew it was absolutely accurate, you are gonna have days where 98% feels really hard and good days where 102% is relatively easy. If you do your threshold in resistance mode, you can adjust your work and aim a little bit higher on good days and lower on bad days. Get in touch with your feel-o-meter. Adjust according. Don’t be a slave to erg mode. Just my opinion.
I tend to think of 105% to 110% steady state intervals primarily as being event-specific. If my events had multiple 6 to 10 minute climbs, I’d be doing them as part of a specialty phase.
Not sure about you, but those for me would have increasing lactate after each one.
For me, the highest power for 10 minute intervals that are really repeatable are at ftp… the old 2x8 test was approximately 111% of ftp and yes, that test produced an ftp that i could do the 4x10 from lamarck.
Depends on how long btwn intervals. If you’re prepping for a 4 lap road race you might have 20 minutes or more btwn climbs and so you’d build a workout with appropriately generous recoveries.
If you’re talking about 4 × 8 with 4 minute recoveries then, agreed, 110% is gonna be very tough. 
In that case probably best to build up from 4 × 6, 4 × 7 and 3 × 8 going as hard as possible while maintaining power across all the intervals.
Not sure what your FTP is but at 300w that’s 6w above threshold. Surprised you feel it that much? Or is my math backward?
@Bioteknik I was just commenting on FRC in general. Just looked at my training plan: FRC intensity is indeed at 105%. 
You can easily feel the difference, especially just above FTP. Not saying it’s not doable in isolation - I am able to do 4x10@108-110 as a single workout, heck I have done 3x(3x6 with 1min brake)@110%, but if you multiply this by many workouts it takes it’s toll. So for specificity - ok, for sustainable training - I can get way better results with doing 4x15-20 just below than 4x10 slightly above. Not to mention daily feeling and variable FTP, PM error etc.
Yup, that’s my experience as well, especially the difference between just below and just above threshold is quite stark. I think I can pinpoint my FTP ±3 W or so. Like you wrote, it doesn’t mean you cannot ride just above threshold, you can, it just feels very different than riding at threshold or slightly below it.
Learned something new today, have been doing some intervals at 105% recently and was wondering why vs at FTP. Thanks!
While watching Wout van Aert and Mathieu van der Poel battle it out at CX Worlds I chuckled when the announcers started talking about FRC (by name) in the final couple laps. Anyone else catch that? edit: was watching on Tiz so I think it was Eurosport or GCN not sure…
