Double Threshold Training: Unlocking Your Running Potential

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What is Double Threshold Training?

Double threshold training is doing two medium to big size threshold workouts in the same day. Typically we do one threshold workout in a day and then wait two to four days before doing another one. With double threshold, you’re stacking them both in the same day.

Why Do Some Runners Experiment With It?

The biggest reason is when we do that first workout, we don’t feel all the fatigue yet. Usually, we feel most of it the next day or the day after. There’s a little window where we’ve already done the work and we know fatigue is coming, but we can still put in some more and build a bigger stimulus.

When you’ve already done one, your body is kind of in that mode. Hormones are heightened, you’re primed to do work, and you’re already in that rhythm. So in that moment it feels natural to get after another threshold workout. People experiment with it because runners are always looking for new ways to improve and whatever it takes to get better.

Can Double Threshold Training Make You a Better Endurance Runner?

For sure it can. It’s incredibly difficult to pull off and it’s much more realistic for professionals. That’s their whole life. They don’t have jobs, families, or responsibilities pulling at them. They can spend the time between sessions eating, napping, and recovering.

What’s Happening Physiologically During Threshold Workouts?

At threshold you’re working really hard aerobically and creating a ton of adaptations. The zone itself is right before the limit where fatigue and muscle waste start piling up. Some people call that lactic acid.

It’s the perfect zone where we can work as hard as possible and get as much adaptation as we can with the least amount of muscle breakdown. That makes threshold the sweet spot. The turnaround time from it is short compared to faster work, where the line goes exponential and recovery takes much longer.

How Could Training Near Threshold Twice in a Day Help?

It just makes the overall stimulus bigger. You’re able to get more total time at threshold and more overall work in that zone, which is a really valuable adaptation. The body ends up responding to that larger amount of work and, over time, endurance and speed can both improve.

Is Double Threshold Better for Advanced or Recreational Runners?

It works a million times better for advanced runners. Honestly, I think it’s a bad idea for recreational runners.

Most recreational runners don’t even know their actual threshold. They haven’t had it tested professionally. Pro runners know theirs through pace, heart rate, or even lactate meters to make sure they’re not going over. Recreational runners don’t.

On top of that, pros usually have a really easy day between the two workouts. If you’re trying to go to work, chase kids, and live your life between two threshold sessions, you’re going to be fried. Even if you get through both, the rest of your week is probably cooked.

There’s also the time-of-day factor. Some people are morning people, some are afternoon people. It’s hard enough to nail a workout once. Doing it at both times of day, with food, hydration, caffeine, and timing to figure out, is incredibly tough.

How Should Runners Focus Their Threshold Training?

The best place to start is figuring out your actual threshold. Use recent race performances, heart rate, or calculators online. Or work with a coach to nail it down.

For most of my athletes, we’re doing threshold twice a week. I don’t program double threshold, but two solid sessions in a week is more than enough to build endurance.

Safety Tips for Double Threshold Training

Number one, you need to know your actual threshold and not push over it. Number two, be smart about your mileage and recovery.

If you only have one day a week to do hard work and want to try it, you could. But most of the time, one bigger threshold workout in a day is plenty.

A better solution I like is pairing a morning threshold with a big lift in the afternoon. That gives you two high-end efforts in a day, but you’re able to execute both at a much higher level. What Is a Flex Day in Running? Then you follow it up with easy days or cross training so your body can absorb it.

Strength training is important, and I like it better as a pairing than double threshold.

Final Thoughts

It’s fun to watch the pros experiment with this stuff and push the limits. Double threshold is one of those ideas that’s cool to see. It might even be fun to try once or twice if you’re curious. But for most runners, one well-executed threshold workout is more than enough.