How to use Training Zones the Right Way (Part 2)

Training zones, lactate threshold, anaerobic threshold, VO2 max: training buzzwords. Do you know what they mean? Do you know how to use them to improve your training? Find out in this three-part series. (read part 1 here.)

Part 2: Finding and Training at and above Lactate Threshold

Last week, we reviewed what lactate threshold is, and how to base a system of training zones around it.

Many athletes do what are supposed to be LT intervals (Level 3) way above LT, not because they are trying to reap the benefits of higher-exertion intervals, but simply because they don’t know they shouldn’t be pushing the pace.

Take “tempo,” for example. All runners know this word. Do all runners know what it is?

Tempo pace caps out around lactate threshold, meaning effective tempo workouts are often done below LT (easier than LT.) Tempo runs improve the body’s capacity for lactate shuttling, the jargon term for clearing away lactate and other metabolic waste. Training at tempo paces improves the athlete’s ability to run longer and faster before hitting lactate threshold. A lot of athletes mistakenly run “tempo” above LT, closer to 10k or even 5k race pace. This eliminates many of the benefits of the workout and leads to under-recovery for future workouts. Not a good combo.

It follows that athletes should know where their lactate threshold is. I am a proponent of knowing how lactate threshold feels, in addition to knowing the approximate heart rate that corresponds to LT. (Cyclists are well-served to also know what wattage corresponds to LT, though other sports can’t yet reap the benefits of working with power meters.) Some athletes may go as far as pricking their own fingers to test blood lactate during intervals, a method my former biathlon coach used regularly. But let’s assume that’s going way beyond what’s necessary for most athletes.

All athletes have access to perceived exertion, and many athletes have access to heart rate data. Neither method is perfect for identifying LT, but both can get you close. So how do we establish these markers?

First, it’s important to understand that LT is not determined by heart rate, it simply corresponds with a heart rate, and as LT changes, it may correspond with a different heart rate. An athlete who has lactate testing done in a lab will learn their precise heart rate at the point of lactate threshold. They can then use this number to track their training heart rate, both determining whether they are training at the correct exertion relative to LT, and also learning what it feels like to sustain effort at LT.

Lactate Threshold Curve

Most of the athletes I work with have not had such lab testing done, and odds are you don’t need to either.

One well-known method for self-testing is the 30 minute time trial or race.

Plan this workout as you would a low-key race: be relatively fresh going into it, pace well (don’t start too hard and fade, but don’t have anything left at the finish,) and warm up/down appropriately. Head outside for this session, as treadmills and bike trainers can mess with perceived exertion. If you use a heart rate monitor (one that is accurate,) your average heart rate over the final 20 minutes of the TT is approximately your HR @ LT. If you don’t use a heart rate monitor, take your own pulse at 10 minutes and at the finish, and average these two.

Now that you know an approximate HR @ LT (and potentially training pace as well, if you’re a runner, or doing some other sport involving relatively consistent training speeds,) practice it. Get to know what this pace feels like, and reap the benefits of some LT training in the process.

Not sure where to begin? Try one of the following workouts:

Warm up and down as you would for any moderate intensity interval workout.

Option 1: Tempo. 20 minutes just below your LT. Keep the pace consistent, and as you fatigue over the course of the workout, focus your attention on relaxing and moving efficiently.

Option 2: 3×8 LT. Three reps of eight minutes at LT. Two to four minutes of easy-paced recovery in between, don’t stand still or walk for recovery.

In each of these workouts, the first several minutes will feel reasonably comfortable, with effort coming to feel moderately uncomfortable, but never race-level exertion, by the end of the session. Practice comes in handy here, because heart rate won’t shoot straight up to HR @ LT; it will take a few minutes at the appropriate pace to get there. If you try get your HR up right away, you’ll be starting at too fast a pace, and after a minute or two, you’ll be forced to fade so as to stay in the appropriate pace range.

To be clear, it’s not that endurance athletes should never train above lactate threshold. It’s just that they should be doing LT training too, and when these “easier” intervals are on the schedule, athletes push too hard. Athletes who write their own training plans may not even know to do LT intervals. Or they might be confused about various terms.

Now that we’ve cleared some of that up, next week we will look at the higher exertion intervals.

Read Part 3

Want help writing your training plan and designing intervals that work? I’ve got you!

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