High / Low Training… What To Do and When.

“In endurance, not only does the magnitude of fatigue matter, but also its nature.” – V. Zatsiorsky, 1966


Endurance – simply the ability to keep doing a task over and over – is something we all feel we need more of from time to time. The problem with gaining endurance is that there are lots of kinds of it and lots of ways to develop it. Endurance is also very specific to levels of intensity – being able to hike for hours doesn’t necessary mean you’ll do better in a 5k, even though you are on your legs and “enduring” for both.


In climbing, endurance is really all about local muscular endurance in the forearm. You don’t ever really reach near your limits in your ability to get or deliver oxygen to the muscles, don’t ever really fatigue any of the large muscle groups, and don’t come remotely close to running out of fuel… so you’d think it might be fairly simple. 


We all know what it feels like when the work outpaces our ability to execute it, but it isn’t clear what to do about it. Our animal brain tells us that simply doing more of what causes the pump is the best way to fight it. Sports science, however, suggests a different method. The general idea is to get better at climbing without getting pumped in order to improve endurance rather than trying to get better at climbing while being pumped


There are three primary energy systems the body uses to produce motion. These energy systems are all functioning at all times, but we can look at it in terms of one system carrying the brunt of the work most of the time. I tend to be a bit more simple-minded than many of climbing’s elite training experts, so I like to think of endurance in terms of the gears in a car: 


FIRST GEAR: Anaerobic Alactic: High Power / Low Endurance (up to about 12 seconds)


SECOND GEAR: Anaerobic Lactic: Medium Power / Medium Endurance (12 seconds up to about 90 seconds)


THIRD-TO-FIFTH GEAR: Aerobic Oxidative: Low Power / High Endurance (90+ seconds) 


We tend to feel the pump best in the Anaerobic Lactic zone, and it’s in this zone that we usually come ripping free of the holds on most power-endurance and endurance style routes. The obvious solution is to get pumped regularly and eventually get better at it. Although this does work for a while, I’ll explain that it’s not the only way, nor the best way, to go.


“Endurance traditionally has been associated with the necessity to fight fatigue and with increasing the athletes tolerance to unfavorable changes in the internal environment. It was thought that endurance is developed only when athletes reached the desired degree of fatigue… Such views linked endurance to a fatalistically inevitable decrease in work capacity… And lead to a passive attitude toward endurance development. ‘Tolerate’ and put up with the unavoidable unpleasant sensations rather than actively search for training means that reduce fatigue, postpone it, and make it less severe…


“Yet the goal is not taking the athlete to exhaustion to accustom him to metabolic acidosis, as it is often understood in athletic practice, but just the opposite… To develop alactic power and to couple it with oxidative phosphorylation to increase the muscles’ oxidative qualities, that is to develop the LME (local muscular endurance).


“So another training principle was proposed to improve endurance: improving the capacity in avoiding the factors which provoked fatigue instead of improving the capacity in tolerating it. This training principle was named anti-glycolytic, minimization of the glycolytic mechanism involvement in the energy supply of the competition event. In short distance sport disciplines it may be obtained by increasing the athletes level of maximal anaerobic power. In long distance endurance sport disciplines it may be obtained by increasing the speed of locomotion or power output, at the level of anaerobic threshold, which is related to the improvement in local muscular endurance.“ – Verkhoshansky, 1988, 2011


In short, training too much in the glycolytic (lactic) energy system is metabolically damaging, not intense enough to create gains in strength or power, and really uncomfortable for the athlete. In a sport like rock climbing, our training goal should be to arrive at the difficult parts of the climb fresh, execute well, and recover quickly. Thus, training anti-glycolytically you are getting better at recovering from very-high intensity efforts and handling more of them per unit time.


General Endurance

“Even the so-called aerobic preparation should be specific [due to local muscular adaptations, specific vasomotor reactions, etc.]. For effective development and realization of aerobic abilities in muscular activity, training must correspond to it in the work mode and in the involved muscles.” 


Even a modest level of aerobic fitness is enough to deliver oxygen to the working muscles. For your low-level endurance work, you will be more interested in improving usage of aerobic energy in the muscles local to the forearm. If you are capable of walking with a backpack for an hour nonstop or jogging for 20 or so minutes, I suggest that you don’t need any more general endurance. Instead, your endurance efforts should focus on either creating more capacity by climbing more total moves per training session (more moderate pitches, easy boulders), or they should focus on doing long, continuous sets of work, such as climbing non-stop for 10 minutes at a time. This is clearly sub-threshold activity, but will lead to greater oxygen transport, greater removal of metabolites, and a more relaxed feeling toward being tired while climbing. Some people call this “ARC” training, which is an acronym for “aerobic restoration and capillarity.” I think this training is too hard to be considered restoration, so we just call it “Extensive Endurance.” 


“Low” Training

Extensive Endurance (Aerobic Capacity)

Sessions will vary in duration based on what the athlete’s total capacity is, but SKILLED traversing, linked problems, or route laps of 5-20 minutes on a 1:1 work:rest ratio are appropriate. Low-skill ARC “open climbing” might be too easy and build bad habits. Intensity should be conversational – athlete should be able to recite the Pledge of Allegiance (if you are an American!) without gasping for breath at any point. HR monitoring might be of use. 


Volume Training

Your goal is not just going to be total pitches, but total pitches at a given difficulty. Climbing grades are difficult to use as measures of intensity, but we do what we can. This type of training day builds day-long capacity and can also help you in recovering more quickly on easy ground. The big reward for doing a lot of mileage is that you will eventually have the ability to do more good tries per day. 


To start, look at what your average pitch count or total footage is in a climbing day. Look back on your log and get an average for the last 10 days at the crag or so. Chances are if you go out and do more than this number, you’ll be pretty tired the next day.


For example, if you average just 6 pitches per day, we want to build up from that about 20-30%, so aim for 8 pitches at any grade. This can include go-again second laps, a TR burn (unless you prefer the TR, in which case you should lead only), or whatever. Once you get your 8, subsequent days should find you adding difficulty to your days for the next 4-5 sessions. Eventually the climbing will get hard enough that the 8 pitches is a real strain… then it’s time to switch it up. Either change to another training type, or go back and up the pitches again, maybe to 10-11 this time, and start again. 

“High” Training

Build strength first, then build endurance, then build strength endurance. Without highly developed abilities, the combination of the two is compromised. Thus, high-low training becomes not only an option, but a necessity. 


The really good news here is that bouldering is both fun and useful for training. Do a lot of it. Occasionally, we will do high-threshold interval work that features work periods of less than 10 seconds with long recoveries. 


High-Intensity Intervals 


  1. High Threshold Intervals. These are very hard efforts separated by near-full recoveries, i.e. they will feel too long. Maintenance loads are suggested for use in-season, development loads for when you are trying to get better overall at endurance. A suggested session would see you do 10 sets on-the-minute, rest 5 minutes, and repeat twice more for a total of 40 minutes training.

3-8 second sets at 80-100%

Rest ~45-50 seconds (Sets on the minute are great here)

Maintenance loads: 10 sets 2-3x per week 

Developmental loads: 20-30 sets 5-6 days per week

Example exercises: Edge Hangs, 2-3 moves on Campus, Explosive boulder problems (4 moves or less), or combos, i.e. edge hang minute 1, campus minute 2, deadlift minute 3…



  • Repeat Serial Intervals. These are slightly easier than the HT intervals above, but can be done for greater volumes. For example you might do a campus ladder that takes 10 seconds once every 50 seconds for 5 sets (about 4 minutes), then rest 3 minutes. Switch to a static hang on a small edge for the same time (10:40). Repeat this pattern for 2 more full rounds, giving a total workout time of about 40 minutes.


6-10 second sets at 65-90%

40-60 seconds rest

5 sets per group

3-5 minutes between groups

2-8 groups per session



  • Non-Specific Interval Supersets.


Same as above protocols, but switch between a continuous-load exercise such as rowing or Airbike, and a strength/power movement for 2-3 reps, such as pull-ups.


  • Boulder Problem Intervals. 

Actual boulder problems fall outside the alactic zone, and can take up to 25 seconds to complete. To stay close to the zone we are trying to train we can use real boulders, but change the ratios. Watch for accumulated fatigue as you will be training in the glyolytic system a bit.

12-25 boulders at 75-90% (at OS level or OS+1), one problem every 2 minutes. 


Using some metabolically specific (duration, intensity, muscle group) activities in combination with climbing can enhance the endurance process and can reduce mental fatigue. Getting a bit creative will help you stick with the plan longer, and may produce some surprising and exciting results.

Glycolytic (Lactic) Peaking

“Intense glycolytic work should only be done after attaining a high level of aerobic preparedness. Intense glycolytic speed work, when the athlete is not prepared for it, leads to an asthenic* reaction that protects the organism against a sharp pH drop. (Pyshnyak, 1982) 

*pertaining to a condition of weakness, feebleness, or loss of vitality.


This is the pump you seek. It feels like endurance, so you’ll want to train it a lot…but be warned: This type of training builds anaerobic endurance quickly, and you’ll go off the back side quickly, too. 


The total number of sessions needed for most climbers to peak their glycolytic system is probably no more than 6-8. This might seem like a small number, but it’s more than many climbers normally can handle, both emotionally and physically. These sessions need to progress, need to be terribly hard, and need to be placed correctly in the training year.


We all know about the standard sessions:


4x4s (4 problems back-to-back at approximately OS-1(1 grade easier than your normal onsight level)  repeated 4 times with on a 1:2 to 1:3 work:rest ratio. Sometimes done as a series of 2 or even 3.)


Linked Problems (Almost always up one problem, down easy climbing, and up another. Done at about OS or OS+1, W:R is usually 1:3 to 1:5, 4-8 sets.)


20 Move Circuits (3 rounds of 5 sets x 20 moves with 45-60 sec between, 5-10 minutes between rounds, continuous movement, sustained.)


40-60 move circuits (5 sets of 40-60 moves with 8-12 minutes between, continuous movement, sustained.)


Consider this progression:

The 3-2-2 These should be done on boulder problems or boulder problems with a traverse-in, for about 10 moves.

RoundsSetsNumber of Sustained MovesRestDifficultyRest Between Rounds
3 sessions21010 :4580-90%10 minutes
2 sessions21010:3080-90%10 minutes
2 sessions3810:1575-85%15 minutes



The bottom line is you should be beating the hell out of getting stronger and more powerful all the time. You can do a bit less from time-to-time, but you really don’t ever get to stop if you want to get anywhere in this sport. 


I suggest doing maintenance loads of HT Intervals once a week, and then a couple of times a year, really go after them for 4-6 weeks. The best time for a Glycolytic Peak is right after a cycle of HT training. 6-8 sessions, then go send the project. Take 3 days off and get back in the bouldering cave. 


Don’t chase the feeling – chase performance. Test yourself on a landmark route or boulder. Do some foot-on ladder to failure tests. Run through the Lattice test…but no matter what, don’t judge your training by how pumped you do or do not feel.



  1. ajpalec on July 27, 2019 at 10:13 pm

    If I wanted to incorporate HT Intervals into a Logical Progression style cycle (Int. St. > Lim. Bould. > IE/EE), where might you suggest placing that session? In place of a Limit Bouldering session? As the energy system day (and maybe incorporate IE/EE on the same day or in between the Integrated Strength and Limit Bouldering day?). I’ve been looking forward to this article since hearing the Training Beta podcast with Steve and reading the earlier High/Low article. Thanks! – Alec

    • Steve Bechtel on July 28, 2019 at 2:45 am

      Hi Alec,
      Two ideas:
      1. Replace the ESD day with HT intervals + some EE work at the end.
      2. Go STR > HT > PWR > IE/EE

      Both should work, you just need to be training frequently enough that you hit strength at least 1x every 10 days in the second example.


  2. Joel Unema on May 4, 2020 at 7:48 pm

    Hi Steve!
    Two quick questions, High and Low.
    High: You suggest (at the end) Maintenance loads of 1 session HT per week and a couple periods per year of getting after it for 4-6 weeks. In the HT description, Maintenance loads are 2-3 sessions per week and Development loads are 20-30 sets 5-6 times per week? This seems like a lot of days to be doing the same session type in a week? Just wanted to check/clarify.

    Low: Also wondering about recommendations for Maintinence and Development sessions per week for “Low” training

    • Steve Bechtel on May 7, 2020 at 12:52 pm

      Hey Joel,
      Great to hear from you. Hope you are doing well down there and are getting ready for more big projects.

      Yes, I see now that this is confusing. The HT intervals are pretty brief, so getting them in for maintenance is pretty easy. Although you might only have one HT-focused maintenance session (where you are actively doing intervals), bouldering and even HB training acts as a continual stimulus that works in conjunction with the training. Just remember anything that is in that short zone will help keep that threshold up. As you’ll recall, this is the exact zone you trained in the demo at the PCC.

      For developmental training, we’re talking about an athlete that has never developed this system well and needs a focused training cycle in this area. In this case, he would be doing almost no other training. This zone would not apply to you.

      “Low” maintenance will vary by the climber. For you, think in terms of total weekly mileage. If in-season you are climbing 2000 feet per week outside, a maintenance load would be about half this, and done at onsight or below. For development, I think the numbers are really high. We are probably looking at 3x per week of over 1000 feet of climbing for someone who does the volume you do.

      I have been studying this type of training a lot over the last couple of years, and I really think that it is the way. Let me know if you learn anything as you test things out.

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