So, you want to get better at climbing? Whether you’re a recent convert or seasoned veteran, welcome to the club. 

Climbing, always a fringe sport in comparison to, say, running, cycling, or swimming, has not historically had scientific backing for even the most basic training protocols. Hangboard routines? Endurance laps? These exercises make intuitive sense but have long lacked research-driven nuance. Luckily, be it due to the growing indoor industry, climbing’s Olympic inclusion, or the collective prayers of our cultish community, this is quickly changing. Over the past decade, the pace of publication of climbing-related research has quickened from a trickle to a torrent, and it’s about time that all of us tuned in.

This article series aims to review present knowledge and current training protocols with an aim to help young guns and old chuffers alike get the most out of their climbing. Psyched? Us too! 

Read Part I here.

Pitch Two: Hypertrophy Training

In technical language, hypertrophy refers to an increase in the axial cross-sectional area of a muscle fiber or whole muscle. In everyday language, it refers to getting swole. 

Hypertrophy is the result of your pre-existing muscle fibers growing bigger, and because bigger means heavier, this sort of adaptation often gets a bad rap in climbing training literature. Common sense dictates that more weight means more gravity which means less sending, and while the logic here is sound, it overlooks one crucial element: strength. If heavier also means stronger, getting swole might not be so bad for climbing—as long as the benefits of the strength gained outweigh (yes, that’s a pun) gravity’s increased pull. 

But does swole actually equal stronger, you ask? Aren’t big muscles just sacks full of (sarcoplasmic) fluid?

The answer here is, well, not always.

The Relationship Between Hypertrophy and Strength

Research shows that the cross-sectional area (CSA) of both muscles and the fibers of which they are composed is a morphological factor of strength. This means that strength is determined, in part, by muscle size. 

The reason has to do with something called sarcomeres—a muscle’s fundamental force-generating units. In both theory and practice more sarcomeres in parallel (i.e. bigger muscles) means more potential force production. This follows the basic mechanical tenet that forces in parallel are additive. 

While the math on strength is complicated by many other factors (including non-contractile proteins and physiological and mechanical changes that accompany hypertrophy), the bottom line is that bigger muscles are stronger. 

The Importance of Strength in Climbing 

Climbing rocks requires strength. And while, yes, it also requires many other things (including technique, strategy, headgame, and safety knowledge) strength is what matters most.  

Study after study shows that the greatest predictors of climbing performance are maximum strength, power, and explosive strength in the upper limbs and finger flexors. Crucially, the strength these studies refer to is relative, not absolute. You don’t need to be as strong as an ox to climb hard unless, of course, you weigh as much as an ox—then you do. 

Hypertrophy benefits climbing as long as gains in strength are sport-specific and positively impact the climber’s strength-to-weight ratio. To achieve this, training variables must be properly set.

Getting Hypertrophy Right

Hypertrophy training is a valuable tool that should be cycled into your regimen alongside blocks of maximum strength and power. However, you need to get it right. Effective hypertrophy depends on properly calibrating (1) load, (2) set endpoint, (3) volume, (4) frequency, (5) rest, and (6) exercise selection. 

Load

Load refers to the magnitude of resistance during training and can be expressed as either a percentage of maximum strength or as a targeted weight and repetition goal (where repetition is defined as the number of times you do an exercise).

Studies disagree about the repetition range that best promotes hypertrophy. As it turns out, load has little impact on muscle protein synthesis (MPS); what matters is effort. Longitudinal research shows no difference between high-, mid-, and low-load training as long as effort level is high. 

Two things are clear, however. First, varying repetitions between weeks and even within a session is likely more beneficial than consistently training with moderate loads. Second, hypertrophy training appears less effective at loads less than 20% of your one-repetition maximum (1RM).

Practical Takeaways

• Repetitions of a given exercise should fall between the range of 5 and 20.
• Effort matters more than hitting a specific rep range. 
• Variation (by either adding weight or employing assistance) is better than consistently doing the same number of reps. 

Set Endpoint

Like so much exercise science, the literature on how much is too much (or not enough) is unclear. Two 2021 reviews and meta-analyses (here and here) present different findings on the value of training to failure. One saw no hypertrophic benefits to failure training; the other found that training to failure promoted significantly more muscle mass increase than non-failure protocols.  

Despite this ambiguity, everyone agrees that beginners can gain significant muscle mass without training to failure. As experience increases, so does the need to push yourself to your limit. This said, training to failure increases the time needed for recovery and should thus be used in limited ways.

Periodized failure training is a viable option. This means going hard before a peaking phase and following this by a tapering period that involves reduced levels of effort.

Practical Takeaways

• Beginners need not train to failure.
• Failure training is important for experienced athletes.
• Hypertrophy training involving failure protocols should be periodized to ensure increased recovery needs do not detract from other training objectives.

Volume

Volume refers to the amount of work performed in a given session. Where hypertrophy is concerned, both acute and longitudinal studies show that more is better—up to a point. 

Higher training volumes trigger a higher anabolic response and increased MPS. However, at a certain threshold increasing workload crosses into overtraining territory and begins to have a detrimental effect. 

The right balance comes down to myriad individual factors. This said, more than 10 weekly sets of a given exercise is a good benchmark (where sets refers to the number of times you do a certain number of reps, so 10 sets of 10 reps would mean 100 total). Further, periodization and a roughly 20% increase in volume per four-week cycle will lead to greater long-term hypertrophic gains. 

Practical Take-Aways

• Effective hypertrophy requires high levels of training volume.
• 10-plus sets per week (separated by adequate rest) of a given exercise is a good benchmark.
• Periodization and a 20% increase in volume per four-week cycle is recommended. 

Frequency

Training frequency denotes the number of sessions performed per week. 

A 2019 systematic review and meta-analysis found weekly frequency does not matter as long as volume targets are hit. That is, if you aim to perform twelve sets of pull-ups each week, it doesn’t matter if you do four on three separate days or six on two. However, research shows that hypertrophy plateaus beyond ten sets per muscle group per session and so twelve sets in a single day would be counterproductive. 

Practical Take-Aways 

• Training frequency does not matter as long as volume targets are achieved, recovery needs are respected, and no more than 10 sets per muscle group per session are performed.

Rest

Rest refers to the time taken between sets of the same exercise or between different exercises in the same session. 

Appropriate rest depends on the type of exercise performed. Multi-joint movements require more rest than their single-joint counterparts. 

Additionally, studies show that trained athletes may see greater hypertrophic gains with longer rest times. 

As a general rule, two minutes is an appropriate rest time between sets of multi-joint exercises, while 60 to 90 seconds is appropriate for single-joint exercises.

Practical Take-Aways

• Multi-joint exercises (like pull-ups) require rest times of two minutes between sets. 
• Single-joint exercises (like biceps curls) require only 60 to 90 seconds of rest.  
• Trained athletes may benefit from extending these rest times. 

Exercise Selection

This element of hypertrophy training packs in numerous considerations. Exercise selection refers to modality (body weight, free-weight, machine, etc.), joint engagement (single- or multi-joint), plane of movement, and angle of pull.

Choosing a range of exercise modalities to target a given muscle produces the greatest gains. Combining single- and multi-joint protocols provides a synergistic effect, leading to whole-body muscular development. Working muscles at their complete range of motion produces the greatest hypertrophic benefit. 

Practical Take-Aways

• Working climbing muscles via a variety of exercise types and styles confers greatest benefit. 
• Hypertrophy is best achieved by exercises that demand full muscular extension and contraction. 

Conclusion

Hypertrophy training is often dismissed as a vanity project that negatively impacts climbing performance by triggering weight gain. The idea that strength gains can happen with little or no increase in muscle mass is pervasive among climbers, and yet the science says otherwise. Maximum strength protocols (i.e. high load, low reps) do, indeed, build strength with smaller mass gains, but progress will be limited unless a training program also cycles in periods of hypertrophy. Bigger muscles aid in strength development by virtue of the fact that increased size means an increased number of sarcomeres in parallel which, in turn, means increased force production potential.

Sample Hypertrophy Training Plan: Pull-Up Protocol

Marvin Winkler earned his BA and MA degrees in sports science at Goethe University, Frankfurt, Germany. He then supervised two climbing-related research projects as a research assistant at the Institute of Sports Science at Augsburg University, where he is currently completing his PhD in performance diagnostics in competitive climbing. When not digging into climbing science, Winkler can be found climbing outdoors, where he has sent routes graded up to 9a/+ (5.14d/5.15a). 

Christopher Schafenacker is a writer and translator who left a career in academia to explore the much more rewarding world of dirtbagging. Previously a visiting assistant professor at the University of Granada (Spain), where he worked on issues of poetry and translation, he now travels full-time in search of storied crags and climbers’ stories.

Together, Winkler and Schafenacker run spring and summer break camps throughout Europe for competitive youth who seek to both improve as climbers and broaden their knowledge of language and culture.