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Fundamentals of Blood Flow Restriction Training for Rock Climbers

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Blood Flow Restriction (BFR) Training for Rock Climbers - Introduction

Blood Flow Restriction is one of the most recent innovations in climbing training. I discovered this finger strength training method when I listened to the 2021 Nugget Climbing interview with Tyler Nelson [1]. I decided I had to try it and was thrilled with the results. After one training cycle of about 6 - 8 weeks, my 7-second finger strength (MVC-7) measured on a 20 mm edge hit an all-time peak of 124 kg! Moreover, I could repeat this result in 2022 with another BFR cycle! Since then, I've been successfully incorporating occlusion training into my finger strength sessions to give my finger strength an edge.

If you want to improve your finger strength with BFR training but are unsure where to begin, this article is for you! And even if you're already familiar with occlusion cuff training methods, you may still find some exciting tips on better applying it to rock climbing training!

Cycling finger strength protocols

Finger strength is one of the most essential factors required for climbing hard. Whether you're into bouldering or sport climbing, finger strength is the common denominator for high performance. Over the years, countless protocols aimed at improving finger strength for rock climbing have been developed, and it's easy to become overwhelmed with the enormous amount of online information available. How do you choose between 7/3 Repeaters, MaxHangs, Density Hangs, Recruitment Pulls, or Velocity Pulls [2][3][4][5]? And which protocol is the most effective at building finger strength?

The fact is that all these protocols can be used to improve our grip significantly, but each of them carries slightly different adaptations. For example, 7/3 Repeaters are known to improve finger strength through flexor muscle hypertrophy, while the MaxHangs or Eric Hörst's "7-53" protocol are used to improve muscle recruitment [6]. To get stronger, you need to address both of these aspects.

But that's not all - you can mix things up by doing 7/3 Repeaters at 85 - 90% MVC-7, resembling MaxHangs, or 7/3 Repeaters at 50% MVC-7, to target anaerobic/aerobic endurance. You can also play with the work-to-rest ratios and try 5/5, 6/4, 10/5, or 30/15 variations, or decrease the edge depth as you move through the cycle. The sky's the limit!

However, no matter what protocol you choose, even if you're making good progress, eventually, your improvement will stall, and you'll need to change to something else. That's why having a vast arsenal of hangboard training routines is necessary. The human body reacts quickly to new training stimuli, so if you haven't tried Blood Flow Restriction training yet, you will likely see spectacular results.

What is BFR, and how does it work?

The impact of blood flow restriction on the human body with and without exercise has been extensively studied, and it is very complex. Research shows that the metabolic stress from vascular occlusion and the mechanical tension from resistance training lead to synergistic increases in muscle hypertrophy and strength through several mechanisms listed below [7].

Type II muscle fiber recruitment

When you exercise under normal conditions, slow twitch muscle fibers (ST) are recruited first, and as the intensity increases, fast twitch fibers (FT) are recruited as needed. One of the most essential benefits of occlusion training is that FT fibers are recruited despite low training intensity. Oxygen availability is severely reduced during occlusion, and progressive recruitment of additional motor units takes place to compensate for the deficit in force development.

That's excellent news for both strength training and injury rehabilitation because you can elicit high levels of muscle recruitment without subjecting your tissues to the wear and tear associated with high-intensity training.

Moreover, greater motor unit recruitment is not limited to muscles distal to the occlusion area. In both upper- and lower-extremity BFR, more proximal muscle groups (glutes, shoulders, and pecs) have been shown to have greater recruitment levels than controls. In simple terms, restricting the blood flow to your arm can also positively affect your shoulder muscles.

BFR under low loads leads to similar recruitment as high-load resistance training.

Muscle hypertrophy

We used to believe that to gain muscle size and strength, we need to exercise at intensities at least as high as 65% 1 RM [8]. However, in 2006, Abe showed that occlusion training produces positive training adaptations, already at 10–30% of maximal work capacity [9]. The factors responsible for improved muscle hypertrophy with BRF are complicated and not fully understood yet, but several mechanisms are believed to be key.

Increased muscle activation

Metabolic accumulation increases the recruitment of type II muscle fibers. This increased activation is vital for muscle hypertrophy because there is a relationship between increased activation and muscle protein synthesis [10].

Increased levels of Growth Hormone (GH)

Growth Hormone (GH) promotes muscle and bone growth and development. Studies have shown that low-intensity resistance exercise combined with blood flow restriction effectively increases circulating GH levels in young people. GH can also promote muscle growth and improve muscular adaptation with mediation by IGF-1. Therefore, an increase in GH levels during exercise may also affect the body's IGF-1 levels to a certain extent [11].

Increased levels of Testosterone

Testosterone is a type of steroid derived from cholesterol and is essential in promoting muscle growth and synthesis and reducing muscle protein breakdown. Researchers believe the high production of lactic acid during BFR training leads to higher testosterone secretion, positively affecting muscle hypertrophy. The amount of secreted testosterone increases as the occlusion pressure increases [11].

Proliferation of satellite cells

Satellite cells are multipotent cells within muscle connective tissue, responsible for muscle growth and regeneration. Initially, researchers thought satellite cells were only activated by high resistance training. However, their proliferation is increased even under low loads with BFR, with associated increases in muscle protein synthesis, myonuclei content, myofiber size, and muscle strength [7].

Recommended BFR cuffs

There are many types of occlusion cuffs available on the market. The simplest and cheapest ones, like the Muscle Forge occlusion cuffs, are tightened manually [12]. However, the issue with such cuffs is that it's difficult to control the occlusion pressure. Such simple cuffs may be a good starting point if you're new to BFR training and want to avoid investing much money in a new training method.

Manually inflatable occlusion cuffs are a step up, and they typically come with a pressure gauge that lets you precisely control the occlusion pressure. My personal choice is the Occlusion Cuff Elite, but other brands are also available [13].

If you're a tech geek with a lot of money, you may go for the wireless-controlled Air Bands [14]. However, unless you're planning on opening a BFR therapy rehabilitation center, this seems like a bit of an overkill to me.

Safety concerns and risks of occlusion training

Regarding medical risks, BFR training appears to be just as safe as any other physical workout routine. Although high-quality research on BFR is limited, most studies do not report any adverse effects at all. Of course, there are several absolute contraindications, such as:

  • Peripheral vascular disease
  • Previous vascular surgery to the affected limb
  • An arteriovenous fistula to the affected limb

There are also other considerations, including:

  • Hypertension
  • Venous thromboembolism (including deep vein thrombosis or pulmonary embolus)
  • Sickle cell disease
  • Haemophilia or other bleeding/clotting disorder
  • Cerebral infarction/stroke
  • Peripheral neuropathy

Such cases must always be individually consulted with a qualified physician. If you're more interested in the safety of occlusion training interventions, the AIS website is a good place to start [15].

However, from a healthy rock climber's point of view, there are also some practical aspects to consider. First, BFR training is unpleasant, or you could even say it's painful, but you should never force yourself to do it if the pain becomes unbearable. In such cases, you should reduce the cuff pressure or stop the training and remove the cuffs. That's one of the reasons why inflatable cuffs are superior to manually tightened ones - it's easier to control the occlusion intensity. Once you tighten the cuffs and start training, your arms will begin to swell, so the effective pressure caused by the cuffs will increase over time. For this reason, you may have to reduce the pressure after a few minutes.

It may happen that you may involuntarily pinch a nerve, or the occlusion pressure will become so high that you'll start feeling an unpleasant tingling sensation, or even impaired feeling in the fingers. If any of that happens again, reduce the cuff pressure or stop the training procedure. You also shouldn't leave the cuffs on for too long. Start with short training drills lasting 10 - 15 minutes, and gradually build up to no more than 30 minutes of continuous occlusion in a session.

Application of BFR in rock climbing training

The standard practical recommendations for BFR training for producing muscle hypertrophy are to use between 20 - 40% of 1 RM, with cuff pressures set between 40% and 80% of limb occlusion pressure (LOP).

Four sets of 15 - 30 repetitions are most commonly used in practice. Generally, rest between sets of 30 to 60 seconds is recommended, with concern that longer periods and intermittent BFR (relieving the cuff pressure between sets) may limit the stress for adaption.

Two to three BFR sessions per week are recommended, in line with recommendations for skeletal muscle hypertrophy in standard resistance training of 2 to 4 times per week. A more aggressive regimen, including twice-daily BFR training, could be a reasonable option to accelerate recovery in the early rehabilitation period following an injury or surgery.

However, across the studies looking at BFR, large pressure ranges have been applied without relative reference numbers such as LOP, limiting standardization of the findings. Nevertheless, high pressures (70%-100% LOP) appear to provide a more potent stimulus to prevent atrophy. At the same time, the most common protocol in these scenarios is 5 minutes of BFR, followed by 3 minutes of reperfusion, for 3 to 4 cycles, once or twice a day for 1 to 8 weeks [7].

BFR 7/3 Repeaters

This exercise is a BFR version of the well-known 7/3 Repeaters protocol. Because we use occlusion cuffs, we must reduce the load to 30 - 40% of the maximum intensity. For most climbers, that will mean operating around their Critical Force measured under normal circumstances (non-occluded state).

For this protocol, I suggest using relatively big hangboard holds, e.g., the 33 mm edges of the BM2k hangboard. Using big edges will allow you to use less counterweight to get the proper training load, which is convenient. However, you don't need to limit yourself to only training on edges in the half-crimp position. You may use the same principles to train pinches, pockets, and slopers. Here are the steps to perform the exercise:

  • Choose the hangboard holds
  • Set the proper training load between 30 - 40% of your MVC-7
  • Put on your occlusion cuffs and tighten them or inflate them to the correct pressure
  • Perform a set of 6 reps of 7/3 Repeaters
  • Rest for 1 - 2 minutes

If you're only starting with this training mode, begin with short sessions of 5 sets. That will accumulate to 10 - 15 minutes under occlusion, which is sufficient. As you get more comfortable with BFR training, you may increase the number of sets to 10 or even 15, making it 30 minutes under occlusion.

Table 1: BFR 7/3 Repeaters protocol summary table.

BFR 7/3 Repeaters
Hang test time [s]5 - 10
MVC-7 load20 - 40%
Sets5 - 15
Hang time [s]7
Rest betw. hangs [s] 3
Rest between sets [min]1 - 2
TUT/arm [s]210 - 630
Total BFR time [min]10 - 45

BFR Finger Curls

The BFR Finger Curls involve concentric contractions of the finger flexor muscles, and in this way, they complement the traditional passive hang exercises. For this exercise, you'll need a portable hangboard and a 20 - 40 kg weight. To perform the exercise:

  • Attach the weight to the portable hangboard
  • Put on your occlusion cuffs and set the proper occlusion level
  • Grab the portable hangboard in such a way that your fingers are extended as the weight rests on the floor
  • Perform a set of 10 - 15 finger curls, lifting the load a few centimeters off the floor
  • Once completed, hang on a fingerboard at bodyweight until failure
  • Rest for 1 - 2 minutes
  • Perform 5 - 15 sets

Table 2: BFR Finger Curls protocol summary table.

BFR Finger Curls
Load [kg]20 - 40
Sets5 - 15
Curls/set5 - 15
Hang time after curls [s]until failure ( > 10 sec.)
Rest between sets [min]1 - 2
Total BFR time [min] 10 - 45

Results of BFR finger strength training programs for rock climbing

For the last several years, I have consistently measured the key parameters of my physical climbing performance, including my MVC-7 and Critical Force on 20 mm edges and my body weight. I've been trying to correlate these measurements with my parallel training interventions. Although this data should be treated as strictly anecdotal, in the case of BFR, I've reached some promising results.

In Figure 1 below, you can see the results of the measurements I've taken from June 2019 until August 2023. Between December 2020 and March 2021, I followed a strict keto diet, which negatively affected both my finger strength and forearm endurance. However, returning to a regular balanced diet, combined with standard hangboard training and climbing, resulted in my finger strength and endurance returning to their previous levels in September 2021.

Figure 1: My personal results of keto diet training cycles and BFR training cycles.

At this point, I decided to try BFR, and by November 2021, my finger strength reached an all-time high of 124 kg, roughly equivalent to 185% BW on a 20 mm edge (+57 kg for 7 seconds). Next, I went for another keto diet cycle. The adverse impact on my forearm endurance was shocking - to date, I haven't recovered my CF level from early 2021. However, my MVC-7 remained relatively stable until August 2022, when I opted for another BFR intervention. I haven't observed any increased finger strength this time, but maintaining it at such a high level was already an achievement. Shortly thereafter, my MVC-7 began to decline as I focused more on sport climbing training and attempts to rebuild my aerobic endurance.

Following a strict keto diet had a shocking long-term adverse effect on my forearm endurance.

There are a few takeaways from this experiment. First, eliminating carbs from my diet had a tremendous negative impact on my anaerobic and aerobic endurance. I felt well overall, but climbing anything longer than a 5-move boulder was becoming a challenge. While that result may be strictly anecdotal, I recommend caution to anyone considering limiting their carbohydrate intake to improve their climbing. If you want to learn more about the keto diet in the context of rock climbing, I have another article devoted solely to this particular topic [16].

The other conclusions are more optimistic. Occlusion training did benefit my finger strength. The positive impact was particularly noticeable after the first BFR cycle, which yielded a +4 kg MVC-7 improvement from a level that was already very high. Moreover, a slight positive effect on my Critical Force was also present, although Endurance Repeaters are a much more effective way of addressing forearm endurance deficits [17].

Blood Flow Restriction (BFR) Training for Rock Climbers - Conclusions

Blood Flow Restriction training is a generally safe method to boost your finger strength. Of course, there are specific contraindications, such as vascular diseases, hemophilia, high blood pressure, cardiac disorders, etc., and these cases must always be consulted with a doctor.

One of BFR's most important benefits is allowing effective muscle recruitment while using significantly less training load. That makes BFR more gentle on the tissues and renders it appropriate for rehab work. It can also be argued that it allows for a higher training frequency, but when it comes to rock climbing training, sticking to 2 - 3 training sessions per week should be sufficient to observe meaningful gains.

Unfortunately, although the efficacy of BFR in sports training is generally well documented, we still lack reliable data regarding its impact on climbing performance. My personal experiences have been very positive, but more research is needed to draw meaningful conclusions. Hooper's Beta has an excellent article on their website if you want to learn more about BFR for rock climbers [18].


  1. – EP 79: Tyler Nelson Nelson — A Deep Dive Into Blood Flow Restriction (BFR), Finger Training, and Doughnut Eating, Jul. 26, 2021. (link)
  2. J. Banaszczyk, StrengthClimbing – Hangboard Repeaters strength endurance protocol, Apr. 8, 2019. (link)
  3. J. Banaszczyk, StrengthClimbing – Eva López's MaxHangs, Apr. 29, 2019. (link)
  4. J. Banaszczyk, StrengthClimbing – Dr. Tyler Nelson’s Density Hangs Finger Training For Rock Climbing, Feb. 28, 2022. (link)
  5. J. Banaszczyk, StrengthClimbing – Dr. Tyler Nelson’s New Active Finger Strength Training Protocols, Mar. 23, 2023. (link)
  6. J. Banaszczyk, StrengthClimbing – Eric Hörst's "7-53" finger strength hangboard routine, Jan. 21, 2019. (link)
  7. Cognetti, D.J., Sheean, A.J., Owens, J.G., 2022. Blood Flow Restriction Therapy and Its Use for Rehabilitation and Return to Sport: Physiology, Application, and Guidelines for Implementation. Arthroscopy, Sports Medicine, and Rehabilitation. (link)
  8. Loenneke, J.P., Pujol, T.J., 2009. The Use of Occlusion Training to Produce Muscle Hypertrophy. Strength aned Conditioning Journal.(link)
  9. Abe, T., Kearns, C.F., Sato, Y., 2006. Muscle size and strength are increased following walk training with restricted venous blood flow from the leg muscle, Kaatsu-walk training. Journal of Applied Physiology. (link)
  10. Wilson, J.M., Lowery, R.P., Joy, J.M., Loenneke, J.P., Naimo, M.A., 2013. Practical Blood Flow Restriction Training Increases Acute Determinants of Hypertrophy Without Increasing Indices of Muscle Damage. Journal of Strength and Conditioning Research. (link)
  11. Yinghao, L., Jing, Y., Yongqi, W., Jianming, Z., Zeng, G., Yiting, T., Shuoqi, L., 2021. Effects of a blood flow restriction exercise under different pressures on testosterone, growth hormone, and insulin-like growth factor levels. J Int Med Res. (link)
  12. Muscle Forge occlusion cuffs (link)
  13. Occlusion Cuff Elite (link)
  14. Air Bands (link)
  15., Blood flow restriction training guidelines (link)
  16. J. Banaszczyk, StrengthClimbing – Ketogenic Diet For Rock Climbers – Pros And Cons – Review, March 1, 2023.(link)
  17. J. Banaszczyk, StrengthClimbing – Endurance Repeaters – Forearm Aerobic Endurance Hangboard Routine, May 2, 2019.(link)
  18. – Hooper’s Beta Ep. 106 — Should Climbers do Blood Flow Restriction (BFR) Training? Research Review. (link)
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