By Steve Bechtel

Anyone who has been in sports for very long has probably heard of the energy systems, or the ways in which our bodies supply energy. When we run down a road for an hour, we are producing energy from a different source than when we pick up a heavy barbell. And when we climb our way into a searing pump, it’s another animal altogether. 

Sport science keeps chasing these definitions around. Whether it is the details of the energy’s specific pathways, the best way to source the energy, or the relative contributions of the energy systems, things tend to change all the time. We love to obsess over the details and can get hung up in some new big word—but getting better at producing energy and delivering it to the muscles is pretty unchanged.

In this way I like to remember that training is like an iPhone. We initiate an “input,” something happens in the phone, and an output comes back to us. Science keeps changing the idea of what happens in my muscles and my brain and my body when I train, but my input (i.e. bouldering) tends to produce the same output (i.e. getting better at bouldering). In this way, I like to keep the energy system idea really simple.

There is an energy system that we can depend on for hours of low-intensity exercise. Basically anything that takes longer than about a minute relies primarily on this system. We get better at using this system by doing more low-intensity efforts. For our purposes, we’ll think of the systems like the gears in a old 3-speed manual transmission, and call this one third gear. It’s the one where we do most of our driving, but it’s terrible for accelerating up a hill, and you definitely can’t use it to start out from a stoplight.

The next gear down, second gear, is great for accelerating, for pulling a trailer, and for bridging the gap between first and third, but it is too weak for starts, and will blow your engine up if you try to use it to travel at highway speeds. In our bodies, this is the system we primarily rely on between about ten seconds and a minute of maximum effort. It’s a painful zone and tends to be really limited in how much it can be improved. What we’re learning now is that the stronger and more conditioned the climber, the less heavily they rely on this zone, and instead “jump” across this zone much more readily than recreational level climbers.

And finally we have first gear, which supplies the bulk of energy for maximum efforts under ten seconds or so. This is called the Anaerobic Alactic system…so you can see why I like “first gear” instead. The Anaerobic Alactic System (AA), also called the creatine phosphate system, or the ATP-CP system, deals primarily with the quick supply of energy (in the form of a molecule called ATP) for fast and powerful movements. Because it relies primarily on the little ATP that is already present in the muscles, supplies run out fairly quickly and fast and powerful movement drops off after just a few seconds. You can test this with a simple all-out sprint test; go outside, sprint down the street at full speed, and note how your movement slows after just a few seconds. Even the fastest sprinters in the world will slow in the final meters of the 100M sprint.

This energy system is never working at 100%, so there is always a little contribution coming in from “second gear”, the anaerobic lactic (AL) system, and “third gear”, the aerobic (Ae) system. When we look to improve the function of the alactic system, we have to look not only at improving its ability to create energy quickly, but its ability to work well with the other systems to increase its ability to keep reloading energy over long periods. This is the simplest of the energy systems - thus the quick turnaround on energy - and is the most dependent on genetic it has the least room for improvement of any of the three systems. That being said, the foundation of strength and power affects this system profoundly, and we’ll see that higher levels of these factors result in great improvements in how much demand for energy your body makes.

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How It Works

Not only does First Gear fuel your body’s highest-powered activities, it also creates very little fatigue due to the short duration that the system is your primary source of energy. Most of the pain and suffering we endure in training comes from operating in Second Gear. 

Try this and see for yourself: (I’m assuming you can do 5-10 pull-ups or maybe more for the purposes of this example.) Do two pull-ups, then rest for 45 seconds. Do two more. Rest 45. Repeat until you’ve done 15 rounds of this; 30 pull-ups in roughly 15 minutes. You won’t be tired. Or pumped. Or sore tomorrow. In a few days, I want you to really push the reps to maybe 1-2 reps shy of your max...right about the time the reps get really hard and your form starts to go. Say you can do eight good 7. Rest 2-3 minutes, then do 7 again. Repeat this for 4-5 sets, or until you get roughly 30 pull-ups in about the same time as you did last time… except by doing sevens instead of twos. The difference you feel is the difference between energy sources. Not only does the rest period matter, but the time you work matters, too. The more time you spend using Second Gear, the more waste you build up, and the more tired you become. 

In climbing, the hardest parts of most climbs are really only a couple of moves long. When you are on a route, you’ll mostly be relying on Third Gear, but First Gear is kicked into play when you get to really small holds, big moves, or hard sequences. Once done, your body will default back to aerobic (Third Gear) metabolism as quickly as possible to recover and continue efficient power output. Therefore, the efficiency of your First Gearr depends highly on the efficiency of your Third Gear. Confused yet? 

When it comes to grabbing tiny holds and doing hard moves, your speed of relaxation really comes into play. Power is both speed of action and speed of relaxation. The better we develop your muscles’ aerobic capabilities, the better your speed of recovery becomes. We’ll cover Third Gear training in a later article, but understand this: if you can boulder way harder than your friends and get owned on routes, Third Gear is the system you should focus your efforts on.

Overall, climbing is most efficient (and fun) if it is primarily driven by these two energy systems. When we become too dependent on 2nd gear (the Anaerobic Lactic system / power endurance), the efforts become very painful and hard to recover from. 

Research shows that improvements in alactic endurance (repeated bouts of short and hard efforts) of just 15-30% can be seen through training this system. This isn’t much if you compare it to the gains you can see in Third Gear training, but there is a double benefit here: a properly designed First Gear session can also result in gains in pure strength. The stronger we are, the less effort we have to put forth for basic movement. Performance on endurance routes aside, climbers that exhibit high levels of strength in the fingers also tend to exhibit higher levels of endurance in the same positions.

Training First Gear

To increase the power output of this system (go harder), you want to keep the exercise set length short (3-8 seconds) and the effort at 90% or above, with long / complete rests. 

To increase your capacity, progress toward longer sessions at the high loads above, with efforts at 80% or harder. Longer total work time at intensity over a training cycle is don’t shortcut this in favor of easier movement.

Before you jump into an “All First Gear” training phase, remember that the interplay of training for pure strength and power as well as development of the aerobic capabilities of your muscles is critical. When exploring the ideas that follow on training this system, keep in mind that this will only represent a portion of your training during only specific parts of the training year. 

Below I have outlined some sessions we have built for First Gear development. In general, an athlete should do at least one session of alactic work per week to maintain her ability, and 3 or 4 per week to develop either more power or more capacity. I highlighted the first five of these sessions a few years back in a series on endurance, but will go into more detail on them here. I will also detail out my favorite alactic interval workout and the way in which we progress this.

Once again, I’ll remind you that you should not feel pumped or winded from these efforts. The result in the short-term will simply be a loss of strength or power. Recovery can take a couple of days. Look for progress not in terms of how tired you get in the training, but rather in the amount of work (loads + sets) you can accumulate.

High Threshold Intervals

This is the basis of most of the training we do for First Gear. You do a hard set of activity, such as a pull-up for 3 hard reps, then rest about 5x as long. On-The-Minute sets work well here, and you can see, as noted above, that you’ll probably gain a lot of strength from these sessions, too. 

I like to do maybe one block of pull-ups for 10 sets/minutes (30 total reps) each week and another upper body exercise on an alternate day, most weeks of the year. If I am really pushing for improvement, I’ll run it up to 20 sets, and do them more frequently. This is high volume training, so it’s essential you look out for overuse “hints.” Progress slowly, and back off if the shoulders, elbows, etc. start giving you feedback. 


3-8 sec sets at 80-100%

Rest ~45-50 seconds 

Maintenance loads: 10 sets 1-2x per week

Developmental loads: 20-30 sets 3-6 days per week

Example exercises: Edge Hangs, 2-3 moves on Campus, Explosive boulder problems, Pull-ups, Explosive Push-ups

We can do combos, i.e. edge hang minute 1, campus minute 2, deadlift minute 3… but that is detailed a bit later.


Repeat Serial Intervals 

I like these for building big capacity, really trying to max out that 15-30% improvement we’re looking for. We go a bit lighter than in the High Threshold Intervals, and can still use OTM as a marker, just make sure to keep the work at 10 seconds or less. 

A fixed board is great for these efforts, but you have to get out of the mindset of doing a full problem, sit-start to top. You’ll probably only get 3-4 moves. 

Do execute, climb 5-10 seconds (don’t fudge it to 12-15…you’re leaving the path), rest the remainder of the minute. Repeat this 4 more times. Then go rest 10-15 minutes. You can do easy cardio exercise between, or do some stretching. Just don’t do anything that is remotely intense! After the rest, do another 5 minute block of hard exercise on the minute. I like to see athletes start with 2 of these blocks, then eventually move up to 4.

Again, you won’t be pumped or sweaty or breathing hard…but if the intensity is high enough, it’s working!

You can do this on a Campus Board, with integrated lifts such as a clean and press or long push press, or even with pull-ups. 


5-10 second sets at 75-90%

45-60 seconds rest

5 sets per series

10-15 minutes between series

2-4 series 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.

Minute one, you’ll row for the entire minute (or maybe 50 seconds, then get yourself unstrapped from the rower), then move on to your high force movement at minute 2. 2-3 hard reps, then rest the remainder of the minute. I like to see these in ten minute blocks, doing 5 minutes in each mode. This tends to focus on engaging the aerobic engine and I do these with athletes that have clear limiters in both First and Third gears. 

After ten minutes, rest 5-10, then repeat. The continuous efforts should be done at a pace you could sustain for 10 or more minutes…you should not be sucking wind when finishing these. Again, if you go to hard, you’ve left the path. 


Boulder Problem Intervals 

Best for building the Aerobic-Alactic relationship

Actual fixed board boulder problems fall outside First Gear, and can take up to a minute to complete. To stay close to the zone we are trying to train we can use real boulders, but change the ratios. 

12-25 boulders at 75-90% (at OS level or OS+1), one problem every 2 minutes. Gathering a pump means you are not resting enough between sets. Increase rest by 30 sec per set if this occurs. 

It should be emphasized that we are training two zones here, so the training for First Gear will be suppressed. This should not be your only training mode. 


Strength-Aerobic Training

These are sessions suitable for combining First and Third Gear training. I like these best early season, during the general training phases. 

To execute, do one set of 3-4 reps at 85%+ strength (pull-up, squat, deadlift, press) followed immediately by a tempo-paced set of the same exercise at 40-50%. The tempo set is 10 reps at 4 seconds per rep, no pausing...each set is exactly 40 seconds. Rest 2-4 minutes, then repeat the pair 3 more times. Do no more than 2-3 exercises per session. 


Alactic Intervals

This workout has become a staple in our programming because of its broad-ranging benefits, flexibility, and simplicity. 

Alactic capacity circuits feature high-intensity efforts performed for 5-10 seconds like in most of the examples above, followed by passive rest. Sport science taught us that these efforts done on a 1:5 or longer work:rest ratio were best, so for many cycles we trained by doing a 5-10 second effort each minute. What we slowly realized was that alternating the focus of the efforts from finger-specific to total-body movements allowed us to cheat the work:rest ratio a bit, and thus the intervals on a 30 or 40 second clock were born. 

The basic set-up is like this: Each set of intervals features 5 exercises done in sequence. You start each exercise at the beginning of a :30 (or :40, see note below) repeating clock, then rest the remainder of the time. In general this gives you about 20 seconds to move to the next exercise. After the 5th exercise, you’ll rest an additional 30 seconds, thus making each round 3 minutes in length. 

The specific recommended starting template is as follows:


0:00 <10 seconds Upper Body Explosive or Edge Hang

0:30 <10 seconds Lower Body / Total Body Explosive

1:00 10 second Edge Hang

1:30 <10 seconds Upper Body Explosive

2:00 <10 seconds Upper Body Strength

2:30 rest full 30 seconds


There is not a lot of time for moving around the gym here. I suggest you grab a couple of tools and set yourself up by the Campus Board. My normal specific session is the following: 


0:00 Campus Ladder 1-3-5-7-9 (on medium rungs)

0:30 6x Kettlebell Swings (~½ bodyweight bell)

1:00 10 second Edge Hang (bodyweight, 10mm)

1:30 3x Campus Doubles (large edges or jugs)

2:00 2x Power Pull-Up

2:30 rest full 30 seconds


The sessions are built on doing several rounds of 3 minutes, as described above. A series of rounds will be done back-to-back (usually 3-6 rounds per series), with a long rest between series. It is possible to change a few of the exercises between series, but don’t get carried away with variety. 

You must continually assess whether your strength and power are staying up. If you start to see a notable decline in output or in exercise form, it’s indicative you’ve reached the end of the effective session length. This is also a time to consider a :40 repeating clock. You simply stick with the same less-than-ten second work time, but give yourself ten more seconds of rest each interval. This tends to benefit your strength and the quality of your movement. 

Don’t get pumped! Going deeper into the training will be counter-productive. In the progressions below, understand that almost all of us will hit a level where we should not add more work, and should stick with the same session for a week or two. This session is appropriate once per week. If you do decide to do this style of session more frequently, only advance the difficulty weekly, not each session.

Being a grown-up about it rather than charging forward into tiredness will produce better long-term results. 


Progression is as follows:

Session 1: 2 series of 4 rounds with 5 minutes between. (29 minutes total)

Session 2: 2 series of 5 rounds with 5 minutes between. (35 minutes total)

Session 3: 2 series of 6 rounds with 5 minutes between. (41 minutes total)

Session 4: 3 series of 5 rounds with 5 minutes between. (55 minutes total)


If your form breaks down or you are unable to complete an exercise, don’t follow the progression. Back off on the exercise, reduce the number of reps per set, or reduce the load. Your feeling at the end of any of these sessions should be tired and powered down, not nauseous and pumped. 

As with most training, start each session with a good warm-up that gets you ready for the explosive and high-intensity work to follow. Also, the 8-10 minutes of easy total-body cardiac output work seems to really help with feeling good after a hard alactic session.

It’s easy to look at something like the sessions above and think that there is way more training to be done than you have time for. I think the true solution is to understand the kind of training that will give you the most value, and to focus your efforts there. Alactic work tends to build strength and high-intensity endurance capacity at the same time. It’s worth the time and effort people put into it, and will deliver far more long-lasting and useful results than getting pumped in quick fatigue-seeking circuits.


Steve is the founder of Climb Strong, and is proud to be the worst coach on the Climb Strong team. A climber for nearly 40 years, he has traveled the globe bouldering, sport climbing, and doing first ascents of some of the world's biggest walls. 

Steve once tried to climb all of the Cathedral Spires in the Black Hills Needles in one push with Mike Lilygren, all 76 of them. Sometimes our failures define us more than our successes.

He is education director of the Performance Climbing Coach organization, and is the author of several books on training for climbing. His next book might never come out, since it seems like no one reads anymore. He lives in Lander, Wyoming, with his wife Ellen, and children Sam and Anabel.



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