by Steve Bechtel

You’ve tried ARC training and you’ve done your share of 4x4s, so why do you still come peeling off the wall just before you reach the anchors? What is it about your energy system development that isn’t working? It might be that you aren’t progressing your sessions, or it might be that you are increasing the difficulty in the wrong way.

I like to keep things simple. Some people think that I do it so that my programming is easier for my athletes to understand, but it’s really because it’s easier for me to understand. One quick look around the internet search for “endurance training for climbing” and you’ll run into a whole host of articles written by some very smart people, but many are so science-heavy you’d need a PhD to fully understand them. I am not such a person, in fact my GPA coming out of college was 2.43 – you can look it up.

In keeping things simple, I refer to all “endurance” training as energy system development. There really is no “endurance” in rock climbing anyway, unless you are doing the Fitz Traverse or something. Everything we do in single-pitch climbing has a finish line. There is only so much time you can spend on a given pitch, and therefore all of your training should be focused around performing for limited periods of progressively harder efforts.

The bulk of your energy system work will be in the form of interval training. Intervals simply allow you to amass more quality hard work than would, say, a long, steady-state effort. Since climbing itself is broken into separate periods of hard effort separated by longer rests, it makes even more sense to train in such a way. Most people, whether they are training boulder problems, 4x4s, ARC, or anything else, work within the realm of some kind of interval.


The problem for most of us is we don’t know what the session is actually doing for us, or how to keep getting better. The first time you do a set of 4x4s, you’re probably going to be sore and fatigued for a few days. Repeat the effort and your soreness and fatigue will be less. A few more sessions, and you’ve fully adapted: now your body is capable of that kind of work. You can imagine there are many ways to again make it hard for yourself, but the fitness you gain can be greatly diverse, depending on the method you choose.

There are four ways to advance intervals. As I said before, it doesn’t really matter what kind of intervals you’re doing…they all advance the same way. The progressions are as follows:

Increasing the difficulty of the climbing.

Over a series of sessions, if you are focused on increasing the difficulty of the climbing in each set, you will slowly increase your power output. This factor is most apparent at the ground-level: achieving harder boulder problems in a bouldering session than you could before means you are a better boulderer! Keeping this mindset as you move to longer problems or to links will continually allow you to develop the ability to do very hard moves under varying states of fatigue. Harder sets don’t directly lead to higher work capacities or to more low-end endurance, though. To improve these factors, you’ll want to manipulate other variables while holding your problem difficulty around the same level. An example progression for a linked problem (climbing one problem, downclimbing on open holds, then climbing a second problem) session would be as follows:

For long-term performance, this is the most important factor to manipulate. Strength and power trickle down eventually, and an interval program built around intensity creates more sustainable fitness.

Increasing distance or duration of intervals.

If you make the intervals longer you begin to develop more aerobic power. This is a good practice if your desired outcome is more steady, low-power endurance. You’ll get better at recovering on the fly, and will improve your ability to do multiple semi-hard moves in a row. Improving in this realm doesn’t translate well to doing hard cruxes while redlining, but is clearly the way to get better at sustained redpoints or traversing boulders.

Remember that short intervals tend to lean more toward power development, and long ones toward single-effort endurance. As the intervals get longer, the body switches primary energy systems, so you’ll see drops in power as you transition to the lower power aerobic system. The power drop is not linear: somewhere around the 90 seconds to 2 minute mark, you’ll feel a massive decline in your “snap.”

It’s not a great idea to increase interval durations more than about 10% per workout. We love to stick to the nice, round, easy-to-count numbers, such as going from 30 to 45 seconds, but this tends to play out in fatiguing too quickly. This can effectively shorten the whole training cycle because of too steep an improvement curve. In truth, we do very little increasing of interval durations in our programs, as I prefer spending whole cycles focused on one duration. If you were to move from a 60 second interval early in the cycle to a 90 second interval later, you might completely switch systems…which could mean undertraining both systems.

Even though I don’t favor progressing duration, this type of increase is appropriate for people new to endurance training or for boulderers looking to make the switch to route climbing. Total session load must be considered, so as you add time per set, you may have to drop some sets to avoid overreaching. A progression might look something like this:

Duration and type of rest period.

By decreasing rest or changing it to an “active” mode, you improve your ability to recover on-route. It’s pretty clear that when you’re on a route that even the rests aren’t all that “resty.” Short of a full-on sit down rest ledge, you’re working harder than most of the people you see at the average gym just to hang out on the jugs. This skill involves improving your threshold levels so that even an engaged position allows you to get something back. Effectively, you’ll be recruiting less muscle and have an increased anaerobic threshold.

In the mid 1990s, I had the privilege of attending a training talk with Jerry Moffat, who explained how he trained for hard route redpoints on boulders. He explained that he’d pick a traverse that he had fairly wired, then climb it using the natural rests. Once he could do it several times, he’d then move to resting on a “crap” hold, and once he’d mastered that one, he’d up the ante again. After a few weeks, he’d feel ready for anything.

Changing rest will have a positive effect on aerobic power, but can negatively affect top-end strength endurance and power. By topping out your ability to deal with the highly acidic game of resting on-route, you naturally detrain your top-end values. It is a tough compromise, but one that there is no way around.

Number of repetitions.

Increasing the number of reps of a given interval will increase the energy system capacity. This is valuable for improving the number of hard tries you’ll put forth per session or climbing day. To start, you should simply try to add one repetition per session. For example, if you decided to increase your 4×4 volume, you might go only to 3×4 and 1×5 rather than leaping to a full 4×5. This would represent a move from 16 to 17 problems (about a 6% increase) rather than a jump from 16 to 20 (a 25% increase). Over the course of a whole training phase, you might work up as follows:


3×4 + 1×5

2×4 + 2×5

1×4 + 3×5



I’ll often get some grief about the slow progress I recommend, but I remind you that we train climbers for next year, not next week. Charlie Francis noted: “It is better to undertrain than to overtrain. You will still supercompensate, but not to the same degree. Once you overtrain, the body will plummet and fight to retain balance. Smaller CNS demands over a longer period of time result in more acceptance and greater improvement, while the rush to get more done leads to uncertainty down the road.”

Although on the surface increasing work capacity seems like a huge win, this capacity, too comes at a cost. I’ve heard more than one top level climber admit that by adding more tries into each day seemed to slow their sending rate. The lesson is that if you get too interested in sustaining work for long days, you trade your desire to go hard on each and every try.

At the most basic level, any type of increase is going to increase your strength-endurance or muscular endurance. After a few seasons on the front lines, though, the gains come less easily and you have to start getting very smart in order to push to higher levels.

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