The traditional 4×4 is a go-to workout for building climbing power endurance—but are you getting the most out of every set? Coach Cameron Horst shares his optimized 4×4 variations to help you maintain intensity, manage fatigue, and maximize your training gains.
The bouldering 4×4 is a widely used training method for improving power endurance. But while the standard protocol can be effective, it has some limitations that may prevent climbers from getting the most out of their sessions.
In this article, I’ll break down the common pitfalls of the traditional 4×4 and share my own twist on the workout—one designed to help climbers of all levels maximize their training stimulus and get more out of every session.
Understanding the Standard 4×4
The traditional 4×4 protocol involves selecting a difficult but sub-limit boulder, climbing it four times with minimal rest between attempts, and then taking a short break before repeating the process for several sets.
The goal is to improve your anaerobic capacity and ability to sustain high-intensity efforts despite accumulating fatigue. To get the most out of this workout, each climb should demand a high level of effort—ideally approaching 90–100% of your maximum, relative to your current level of fatigue.
However, repeatedly climbing the same boulder four times presents two main challenges.
Pitfall #1: Choosing a boulder that’s too difficult.
If the boulder is too close to your limit, fatigue will likely catch up with you by rounds three and four. You may fall before completing the climb, meaning you can no longer maintain the intended intensity or complete the planned volume.
Pitfall #2: Choosing a boulder that’s too easy.
On the other hand, if you can comfortably send the boulder all four times, the first couple of rounds may not provide enough intensity to challenge your power-endurance system effectively.
Either way, you’re missing an opportunity to optimize the workout. The goal is to accumulate multiple high-intensity efforts while managing fatigue—not to make every round either a struggle to finish or a relatively easy send.
My Twist: Use Two Boulders Instead of One
To get more out of the standard 4×4, I recommend selecting two different boulders for each set.
Here’s how it works:
- Rounds 1–2: Choose a boulder just below your limit—one that’s challenging but reliable enough for you to send twice with minimal rest.
- Rounds 3–4: Switch to a slightly easier boulder that still requires a high level of effort, especially as fatigue builds.
This adjustment helps you maintain a higher level of intensity throughout the set. Rather than struggling to complete the same near-limit boulder four times or cruising through a boulder that’s too easy, you can better match the difficulty of each climb to your increasing fatigue.
The result? More consistent, high-quality efforts and a better opportunity to maximize the training stimulus of your 4×4 session.
Advanced Variation: Four Different Boulders
If you’re an advanced climber, you can take this concept a step further by selecting four unique boulders per set.
In this variation, each boulder is climbed once, with minimal rest between climbs. Choose four problems that are appropriately challenging and progressively manageable as fatigue accumulates. Each should push you toward your limit without making it unrealistic to complete the set.
A typical workout might look like this:
- 4 different boulders = 1 set
- 3–4 total sets
- Minimal rest between climbs, followed by a longer recovery between sets
The key is selecting problems that allow you to maintain a high level of effort across all four climbs. Adjust the difficulty to your ability and fatigue level so you can accumulate quality work without letting your technique deteriorate.
Want to Make It Even Harder?
For an additional challenge, advanced climbers could experiment with wearing a weight vest during their 4x4s.
Adding external load increases the demands of each climb, so you’ll need to adjust your boulder selection accordingly. Focus on relatively straightforward, high-percentage problems that allow you to climb powerfully and consistently under load, rather than intricate, limit-level sequences.
Unless you’re Adam Ondra, you probably won’t be sending your hardest double-digit V-grade projects with a weight vest on! 😂
As always, introduce added load conservatively and prioritize good movement quality over simply making the workout harder.
Learn From the Best: Adam Ondra’s Approach to 4x4s
Speaking of Adam Ondra, he has shared his own approach to 4×4 training in a video that’s well worth checking out, especially if you’re an advanced climber looking to refine your power-endurance training.
Watch it here: Adam Ondra’s 4×4 Training Approach
The bottom line: effective power-endurance training isn’t just about accumulating fatigue. It’s about choosing the right problems, managing that fatigue, and maintaining the intensity needed to challenge your body.
Experiment with these variations, find the approach that best matches your current ability, and make every set count!
Copyright 2025 Cameron T. Horst | All Rights Reserved
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