Threshold Training-John Karrasch

Threshold Training-John Karrasch

“Threshold Training: Where Party Pace and The Pointy End Converge”

‌I think training gets a bad rap sometimes. With more professionals entering gravel events, there is an obvious pushback from some riders that are just there to finish, have fun with their friends, or beat the time cut they missed last year. It is easy to throw structured training in with other “too serious” things and ignore it. Don’t fall for that trap! A good friend of mine signed up for his first endurance event this year and I offered to help him train for it.

‌He hadn’t done any real training so I was wary of how he would do with a program, especially one with harder Threshold zone riding in it. He did great and had a major feeling of self accomplishment completing the workouts I gave him. I truly realized how important this was after looking over his heart rate file from the race…it had lots of Threshold time! Riding hard is part of riding off road, no way around it. Headwinds, steeper climbs, time cuts. Failing to meet these challenges is just as important to casual riders as it is for pros to not get dropped from the lead group 150 miles into a big race!

‌In our Tempo ride article, I mentioned it was the first training Zone above the first ventilatory threshold (VT1). Threshold work, often called Zone 4, is also above VT1 and takes us right up to VT2. VT2 is where breathing turns to rapid gasping and you are really hoping the crest of the hill you are on isn’t much more than a minute up the trail. Moving past VT2 gets you into VO2 Max work, which I will cover soon.

‌For the power meter users out there, Threshold training is between 90% and 105% of your Functional Threshold Power (FTP). Heart rate will be between 94% and 99% of your Lactate Threshold Heart Rate (LTHR). Both of these should be anchored by the most important abbreviation of them all, your RPE! Rating of Perceived Exertion is what truly helps an athlete figure out how hard they should go on the workout of the day. Remember that training zones are simply ranges to target, and there is nothing magical changing over between 89% and 90% of your FTP!

‌Training in this Threshold zone will make you faster at almost every race distance out there. Yes, bikepackers, I’m talking to YOU. Y’all need to ride hard some also. Even if you don’t ride that hard in the event you have coming up! Moving your Threshold power up gives you more breathing room below that to ride.

‌Threshold training is hard, and goes quickly to impossible if you have your training zones set too high! To get the most from your Threshold training, you need to set some accurate training zones by doing a field test. I won’t cover that in detail, but instructions are simple enough to find and implement. Be aware that for consistent and experienced riders, LTHR won’t change much over a season but FTP will.


Be sure to warm up well before doing these. Include 10-15 minutes of easy riding and a few harder 30 second efforts to get your body ready to push hard. You have to actually do these for them to help, so don’t smash yourself by trying to do every single workout at 100% of your FTP! Much can be gained from the middle of this training zone, and towards the lower end often is referred to as Sweet Spot Training. Heart rate will lag behind power, so give yourself a couple minutes to see what your breathing is like. Breathing will be labored and you shouldn’t be able to talk very much while doing these. It is no secret you are working hard if someone is near you! The exact correct effort will depend on the day. If you are really worked over, you might be better off riding easy and trying again the next day. If you feel better than usual, push a bit harder or extend the time of each interval some. Be careful trying to do these with a group as they are best done solo to stay at the correct intensity. 10-15 watts below your FTP is a really good goal for longer intervals. You can build some serious fitness this way without feeling like you are about to die on each workout!


The best way to keep track of your effort is through efficient use of the screen options on your GPS. Have a Lap Screen for Threshold rides that will show you Time, current heart rate, current power, and Normalized Power for the lap. Cadence is nice here also. Average heart rate for the lap isn’t quite as useful while you are out making the effort, so I don’t bother with it. For power meter users, the 3 second power and normalized power metrics really help dial in your effort. You can also have a “Time In Zone” feature on your screen to keep you honest about the total Zone 4 time you are accumulating.


Don’t get fancy here. They are hard enough to get done without extra manipulation. Keep a self selected cadence, with some awareness that a really high cadence will spike heart rate and a really low cadence will trash your legs early on. Both of those make it tougher to complete the intervals. If the demands of your race will require threshold efforts at some specific cadence, you can include some of these rides in your final prep block. During a block designed to increase Threshold power, keep the goal the goal!


The most productive interval lengths for Threshold work are between 10 and 20 minutes. I will sometimes use intervals down to 5 or 6 minutes, but these are merely to let riders get used to the intensity before beginning 10 minute intervals. Total interval time can go from 20 to 60 minutes. One thing to keep in mind is progression. You should be able to increase the interval time and the total time in the zone with Threshold intervals. Don’t feel like every session has to be the standard 2 x 20 minutes. Rest periods between intervals should be about half the time of the interval. You can also try ascending or descending time periods for your intervals. Don’t underestimate the motivation of some novelty or the unknown here and there in your training.


You can do these on an indoor trainer of course, but many people struggle to complete them at the correct intensity! The best options are a flat, non technical road or a long climb. One of my favorite ways to do Threshold intervals is on a loop course that has a long climb and short descent. Rolling terrain can be a deal breaker here, as the slight downhills will make it very tough to keep the power in range! Oh, and if you are inside for these, a good fan is your best friend. Some riders will have a bit different power targets for indoor and outdoors, but avoid the temptation to overcomplicate it with totally different training zones! I like to have athletes take advantage of the terrain that is convenient to them, then we can fine tune power zones to suit that. I have a steep hill behind my house that takes 5-6 minutes to ride up. That is a bit on the short side for Threshold work, so I simply do them at 100% to 105% of FTP and do a total of 40-50 minutes in Zone 4. These are NOT a good type of workout to try in groups or really with another rider at all if you are trying to stay together.


Threshold intervals will typically show up in training between Base/Prep work and final race prep work. They are hard, so really not that great to do week in and week out all year. That is a good way to burn out and be on the hunt for a new hobby! Twice or three times a week is often a good way to implement these, and can be done on back to back days for more advanced riders. One can also make a case for a mixed intensity week with one day of VO2 Max work and one day of Threshold work. You can also integrate Threshold intervals into your long ride of the week with a loose structure of something like “Ride 4 hours with a long, hard climb every hour.”

Regardless of your event goals, this type of training is THE most important thing you can do to improve your fitness. Within a week of riding, it is totally possible to have some hard, solo workouts AND some easy rides to the coffee shop with your friends. This is exactly what Alison Jackson did leading up to her Paris Roubaix win this year. Have fun and don’t forget that sometimes going a bit faster IS more fun!

Back to blog