Favorite Workout: Uphill Threshold Intervals
By Sophia Etienne, GRP Trail Running athlete
Threshold is a term commonly used in endurance training and refers to your lactate threshold (LT). Or the point where lactate (a byproduct of hard exercise) begins to build up in the blood faster than your body can clear it. Once you’re past this threshold, you’re really hurting.
Lactate is produced as our bodies use glucose, and along with this lactate comes fatigue. It’s that point in a run where your legs start to burn and you don’t have too long until your work rate has to either slow significantly or risk stopping altogether. Threshold training helps get your body used to steady lactate production and clearance. According to running coach David Roche, “improving this lactate shuttling mechanism can improve all performance, even at very high or somewhat low intensities.”
For the sake of simplicity, not just for this article but for my own sanity, I’ll reference a couple of basic zones to classify lower intensity ranges. These are from an article in Trail Runner magazine:
Zone 1: “training your base.” Under the first ventilatory threshold, or 2 mmol of lactate (think very easy running up to more steady running for advanced athletes)
Zone 2: this is the sweet spot that I’m referencing in this workout! Between the first and second ventilatory thresholds, generally between 2 and 4 mmol of lactate (think steady running to traditional threshold, or approximately 1-hour effort)
I don’t have someone checking my lactate for key workouts, so these zones are based on rate of perceived effort or heart rate zones. Paces will be different for everyone, and that’s why I love this type of workout. You start to get used to how different effort levels feel, without the need for constant external testing. By all means, you can utilize lactate levels and/or heart rate, but if you don’t have the tools or wherewithal for either, you can go by effort.
Why We Do It
Threshold training helps you run faster for longer by teaching your body to clear lactate efficiently while improving aerobic capacity. So, basically, you’re inching back your point of blow up so you can push harder for longer when it comes to race day. Some other ways to describe this intensity level are “1-hr effort” pace, half marathon or 10k pace, or “comfortably hard.”
In trail running, we can’t easily or accurately use pace as a guide for effort. The changes in terrain make it impossible to hold a steady pace like a track workout, so we have to use other methods to measure our training stimulus. In the case of threshold training, we can target this with uphill running. Reaching the level of exertion needed to train this lactate shuttling system would take much faster running on flat ground, and running uphill is more applicable for the types of trail and mountain races we are training for.
How To Do It
Find your lactate threshold feeling: the pace you can hold that feels tough but not impossible to hold for an hour. If you want, you can measure your lactate and use the levels listed above, or you can use heart rate by aiming for 80–90% of your maximum heart rate (HRmax), commonly 160-170 beats per minute. Here’s an article about finding your training zones. If you choose to measure your lactate threshold, use it as a guide so you can go by feel during your next workout (instead of constantly checking your HR).
The workout: 3-5 x 8 minutes uphill at LT.
Warm up with easy running for 2-3 miles or at least 20 minutes.
If you’re outside, warm up by running to your favorite (long) hill. This takes some planning, 8 minutes is a longer uphill than you think. Long gravel hills and ski areas are common around my home in Vermont (lucky me?).
3-4 x 8 minutes uphill at lactate threshold.
A “comfortably hard” effort - you can speak in short phrases, but holding a conversation is tough.
Grade matters. If your hill is steep and you have to hike, consider if that’s the mechanical system you want to train that day. As a running workout, the goal of these intervals is to run as much as possible (think “granny gear”).
Don’t have a big ol’ hill? This is a great workout for a treadmill, just set your grade and go.
Cool down with easy running for 2-3 miles or at least 15 minutes.
Easy run back down that hill after your last rep, or flatten out that treadmill. Shake out the legs, relax the shoulders, and pat yourself on the back. That’s a tough workout!
