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Dr. Tyler Nelson’s Density Hangs Finger Training for Rock Climbing

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Dr. Tyler Nelson's Density Hangs - Introduction

Ever since rock climbing began to be perceived as a sport, people started looking for ways to get better at it. Although what combination of skills makes someone a great climber remains a mystery, undoubtedly strong fingers are one of the essential qualities you need to send hard grades.

It wasn't long before climbers realized that hanging off the tips of your fingers on small edges is a simple and effective way to improve finger strength. Thus, fingerboards were born. Since then, many different ways have been invented to develop specific finger and forearm muscle qualities, such as hypertrophy, recruitment, and endurance. However, the first finger training method was hanging on a narrow edge for as long as possible.

Shortly thereafter, climbers began adding more variety to this rudimentary training method. Repeaters, MaxHangs appeared and hanging until failure began to be seen as potentially dangerous to the shoulders 12. Only recent scientific discoveries in the structure and function of muscles and tendons allowed us to appreciate the benefits of long-duration isometric dead hangs. So let's dive in and see how going back to the roots of fingerboard training could help you revamp your climbing and potentially get you rid of nagging injuries such as tendinosis.

Dr. Tyler Nelson - at the cutting edge of rock climbing science

Before we move on, let me introduce the person who has rekindled the interest in long-duration isometric hangs for rock climbing training several years ago. Dr. Tyler Nelson is a certified NSCA Strength and Conditioning Specialist and the co-founder and a content creator for The Performance Climbing Coach seminar series, The Camp 4 Human Performance Climbing Assessment, and The Bstrong BFR Certification Course. He is a passionate climber and does invaluable research on methods to enhance climbing performance, the results of which he often shares through his Instagram and his YouTube channel 345.

Dr. Nelson developed a number of effective finger strength training protocols based on solid scientific evidence. His routines are safe and easy to implement, as he prefers to use autoregulatory protocols rather than hanging off your fingertips with dozens of kilograms attached to the harness. His Recruitment Pulls and Velocity Pulls are exciting techniques that deliver stimuli distinct from traditional hangboarding and often help climbers overcome performance plateaus 6.

Moreover, he effectively popularizes blood flow restriction (BFR) training among the climbing community. His system allows achieving strength gains at low loads while managing finger, elbow, and shoulder injuries 7. However, I believe that his best-known protocol and one that first made him famous are the so-called Density Hangs, which are the subject of this post.

What are Density Hangs?

Density Hangs are a medium-intensity hangboard routine where you hang off an edge for 20 - 40 seconds. The exercise promotes hypertrophy of the forearm muscles and the muscle-tendon junctions, hence its name. Density Hangs additionally trigger advantageous remodeling of the tendons, making them more robust and reducing injury risk.

Interestingly enough, Density Hangs are very similar to the less known SubHangs, developed independently and in parallel by Dr. Eva López 8. The main difference between the two methods is the underlying philosophy. SubHangs, as discussed in one of my previous articles, were designed as an endurance training protocol, aiming to improve the phosphocreatine (PCr) recovery and the total PCr levels in the forearm muscles. In addition, some muscle hypertrophy was also expected due to anabolic hormone secretion, caused by lowered blood pH and fast-twitch muscle recruitment.

Dr. Nelson's structure-oriented approach aims at building thicker and denser tissues and promoting tendon health through a specific sliding effect occurring in the tendons during long-duration isometrics. In this way, a solid muscle-tendon system is formed, allowing for handling higher training loads and increasing finger strength safely and effectively.

Density Hangs protocol details

  1. Choose 2 - 3 hold positions for training. Consider:
    • Slopers
    • Half crimp
    • Open hand
    • Full-crimp
    • Pinch (you may use pinch blocks)
  2. For each position, choose a hold on which you can hang with two arms between 20 and 45 seconds, ideally without added load.
  3. Perform a set of Density Hangs:
    • Hang for 20 - 40 seconds.
    • Rest for 10 - 20 seconds - use 2:1 hang to rest ratio.
    • Perform 2 - 3 reps - until you fail.
    • If you can do more than 3 reps, you can add 1 – 2 more, or increase the duration of the last rep until you fail.
  4. Rest 3 - 5 minutes
  5. Repeat the set for the same hold position or move to the next position.
  6. For each hold position, perform 2 - 3 sets. That amounts to 4 - 9 sets per training session.
    • According to Dr. Nelson, doing 8 sets is often the ideal training volume.

Table 1: Density Hangs protocol summary.

Density Hangs
Hang test time [s]20 - 45
MVC-7 load55 - 85%
Sets4 - 9
Hangs/set2 - 3
Hang time [s]20 - 40
Rest betw. sets [min]3 - 5
TUT [s]80 - 900
Total time [min]10 - 100

Density Hangs protocol remarks

  1. Focus on slow static loading until muscular failure
  2. Density hangs are ideally performed without added load, at around 75% of maximum strength (MVC-7)
    • To calculate your Density Hangs loads and training edge sizes, you may use my Hangboard Training Calculator 9.
    • Strong athletes should consider doing multiple reps until failure (Repeater style) instead of adding load - 2:1 hang to rest ratio works well in this case.
    • If you are strong enough, you may experiment with one arm hangs - it may be necessary to use a pulley setup or a rubber band for assistance.
    • It is better to use relatively large edges (20 - 35 mm) to reduce the risk of finger injury.
  3. Progress by increasing the time to failure on the chosen edge size or drop the edge size if you can hit 30-seconds easily.
    • Be careful not to overdo training on small edges – it puts a lot of stress on the fingers, particularly at high training volumes.
  4. To add variety to your hangboard sessions and to maintain an elevated heart rate, you can make circuits, to include lower extremity and upper extremity (bar isometrics) workouts in between individual hangs.
  5. A typical training cycle is 4 – 5 weeks.

Understanding Density Hangs - basic tendon anatomy

To better understand how Density Hangs work, let’s quickly recap the basic tendon anatomy. As all connective tissues, tendons consist of collagen fibers, an extracellular matrix, and cells (mostly tenocytes). Although they are solid, tendons are highly hydrated and contain approximately 70% water. Their structure closely resembles a climbing rope, with many thin twisted yarns wrapped in an outer sheath.

Single collagen molecules (tropocollagen) aggregate into structures called fibrils, and multiple fibrils form fibers (Figure 1). The fibers are curly, which allows them to absorb energy easily 1011. Fibers are bundled into cable-like structures, the fascicles, encapsulated by the endotenon — a cuff of connective tissue providing vascular supply 12.

schematic illustration of a tendon structure
Figure 1: Schematic representation of tendon anatomy 13.

In large tendons, fascicles are arranged into tertiary bundles, enclosed by two separate cuffs — the inner fibrous epitenon and the outer loose alveolar paratenon layer. These cuffs carry nerves, blood, and lymphatic vessels 14. In addition, tendons constantly subjected to high loads, such as the finger flexors, contain synovial tendon sheaths. Their role is to produce the synovial fluid, which provides lubrication to reduce friction during movement and stress.

Density Hangs for injury prevention - tendon stiffness and the collagen sliding effect

The division of each tendon into smaller strands allows uniform distribution of the loads and decreases the risk of injury 15. The strength of the tendon is determined by the density of the collagen fibrils, their length, orientation, and intermolecular cross-links.

As explained by Dr. Keith Baar in the Just Fly Performance Podcast, when loaded rapidly, the tendon acts as a uniform sheet, and there are practically no shear forces between individual collagen fibers. As a result, no collagen cross-links are broken, but new ones are formed. Having more collagen cross-links means that the tendon becomes stiffer 16.

Instead, suppose the same exercise is done slowly, using a high load. In that case, the collagen fibers and fascicles start sliding relative to each other, and the tendon begins to relax. Consequently, the muscle is pulling hard and shortens, but since there is no overall movement of the joint, the tendon becomes longer - an effect called creep. If done right, you can break more cross-links during the exercise than you resynthesize during recovery, and the tendon becomes more compliant.

Now the question is, why would you ever want to reduce tendon stiffness? After all, stiffer tendons lead to an improved rate of force development (RFD), contact strength, and performance. Of course, all this is true, but if the tendon stiffness is too high relative to the stiffness of the muscle and the muscle-tendon junction, that can lead to muscle pulls and injuries.

On the flip side, according to Dr. Baar, when we exercise with slow, long-duration isometrics with sufficient intensity, we naturally also affect the muscle. When the muscle is subjected to a high load, a massive increase in collagen synthesis and a decrease in collagen degradation follow. Consequently, the matrix around the muscle becomes more collagen-rich, stronger, and stiffer.

Therefore, by using high-intensity isometrics, we can increase the stiffness of the muscle and the muscle-tendon junction while decreasing the stiffness of the tendon. As a result, we end up with a system that’s maybe a little less stiff overall but much less prone to injury. That’s exactly why Dr. Nelson’s protocol is called Density Hangs – it’s about increasing the density of the muscle and the muscle-tendon junction, and not the tendon itself.

Density Hangs increase the stiffness of the muscles and the muscle-tendon junctions while decreasing tendon stiffness.

It is important to note that the sliding effect can be achieved with any mode of muscle contraction, be it concentric, eccentric, or isometric, as long as the movement is slow and the load is high. However, as Dr. Tyler Nelson explains, in climbing training, isometrics are often chosen due to their specificity and because they are much easier to execute correctly without supervision.

Density Hangs in tendinopathy treatment - the concept of stress shielding

In sports literature, Density Hangs are classified as long-duration long muscle length (LML) isometric contractions. This type of exercise has a particular tendon-healing effect. The key here is that the load and the duration of the contraction are sufficiently long to overcome the so-called stress shielding phenomenon 17. We aim to recruit the entire muscle and, consequently, load the whole tendon cross-section, including its damaged parts.

Dr. Nelson and Dr. Keith Baar beautifully explained the concept of stress shielding in their videos 1819. If we suffer from tendinopathy, using light loads and high movement velocity will not permit us to transfer the force through the damaged portion of the tendon, which is necessary to promote healing. On the contrary, high-velocity exercises increase the tendon stiffness and compress the affected area, causing aggravation of the symptoms and further deterioration of the collagen matrix.

However, suppose we slowly apply a high-intensity load through the tendon for an adequate amount of time. In that case, we can stimulate the haphazardly oriented damaged collagen molecules to align correctly with the rest of the fibers. That is the exact reason why high-intensity eccentrics are recommended for treating Climber's Elbow, as I explained in one of my earlier articles 20. Thus, properly executed Density Hangs can be a suitable therapeutic intervention for climbers struggling with finger and elbow pain.

Repeaters vs. Density Hangs

A question arises, is there a practical difference between typical 7/3 Repeaters or IntHangs and Density Hangs? All three protocols are done at similar intensities, around 60 - 85% of the maximum, and result in a similar TUT. Research results indicate that when the intensity of training is equalized, the magnitude of strength and hypertrophy gained depends on the total contraction duration per training session rather than per repetition 21. You could argue that Density Hangs might be slightly better at eliciting the sliding effect of the tendons because the effort is continuous, but there's no evidence that I'm aware of to support this claim.

I learned from Dr. Nelson that if his athletes are strong enough to hang for more than 40 seconds at bodyweight, he infrequently suggests that they add load to Density Hangs. Instead, he'll have them do more reps (Repeaters) or hang to failure (continuous hangs). He recommends using a 2:1 work to rest ratio for Repeater style protocols. That means, e.g., doing a 30-second hang at bodyweight, resting for 15 seconds, and repeating this pattern once or twice until the climber cannot hang reasonably long anymore. This approach adds variety to continuous Density Hangs and brings about comparable therapeutic results based on Dr. Nelson's experience.

Density Hangs - summary

Density Hangs are one of my favorite finger training protocols. I usually recommend using them off-season to help climbers recover their tendons after long periods of projecting hard climbs. Density Hangs, or more generally, long-duration isometric hangs, safely trigger hypertrophy of the muscle, the muscle-tendon junction, and the periosteum while simultaneously reducing tendon stiffness. That makes the entire muscle-tendon mechanical system more robust, less prone to injury, and capable of handling heavier training loads in the future.

Dr. Nelson's method is also excellent for warming up and tendon rehab. The exercise offers a high TUT at relatively high loads of about 75% maximum intensity, making it possible to recruit the full cross-section of the muscles and tendons. This fact lets us overcome the stress-shielding phenomenon and provide a therapeutic stimulus to the damaged areas of the tendon, which would remain unaffected if we used light loads and short TUT.


  1. J. Banaszczyk, StrengthClimbing – Hangboard Repeaters strength endurance protocol, Apr. 8, 2019. (link)[]
  2. J. Banaszczyk, StrengthClimbing – Eva López MaxHangs Hangboard Routine For Finger Strength, Apr. 29, 2019. (link)[]
  3. (link)[]
  4. (link)[]
  5. (link)[]
  6. T. Nelson, The "Simplest" Finger Training Program,, Oct. 16, 2019. (link)[]
  7. The Nugget Climbing Podcast, Ep. 79: Tyler Nelson, Jul. 26, 2021. (link)[]
  8. J. Banaszczyk, StrengthClimbing – Eva López SubHangs Strength Endurance Protocol, Nov. 1, 2019. (link)[]
  9. J. Banaszczyk, StrengthClimbing – Hangboard Training Calculator for Rock Climbing, Jan. 5, 2022. (link)[]
  10. Roberts, T.J., Azizi, E., 2010. The series-elastic shock absorber: tendons attenuate muscle power during eccentric actions. Journal of Applied Physiology. (link)[]
  11. Franchi, M., Fini, M., Quaranta, M., De Pasquale, V., Raspanti, M., Giavaresi, G., Ottani, V., Ruggeri, A., 2007. Crimp morphology in relaxed and stretched rat Achilles tendon. J Anatomy.(link)[]
  12. Paavola, M., Kannus, P., Järvinen, T.A.H., Khan, K., Józsa, L., Järvinen, M., 2002. Achilles tendinopathy. The Journal of Bone and Joint Surgery-American Volume. (link)[]
  13. de Cassia Marqueti, R., Vieira de Sousa Neto, I., Reichert Barin, F., Vieira Ramos, G., 2019. Exercise and Tendon Remodeling Mechanism. Tendons. (link)[]
  14. Jozsa, L., Kannus, P., Balint, J.B., Reffy, A., 1991. Three-Dimensional infrastructure of Human Tendons. Acta Anatomica. (link)[]
  15. Kjaer, M., 2004. Role of Extracellular Matrix in Adaptation of Tendon and Skeletal Muscle to Mechanical Loading. Physiological Reviews 84, 649–698. (link)[]
  16., Dr. Keith Baar on Tendon Health, Rehab and Elastic Power Performance , Just Fly Performance Podcast #156. (link)[]
  17. Orchard, J., Cook, J., Halpin, N., 2004. Stress-shielding as a cause of insertional tendinopathy: the operative technique of limited adductor tenotomy supports this theory. Journal of Science and Medicine in Sport.(link)[]
  18. Stress shielding, C4HP – Dr. Tyler Nelson,, Oct. 05.2020. (link)[]
  19. Stress shielding demonstration, Keith Baar - @MuscleScience,, Jan. 24.2020. (link)[]
  20. J. Banaszczyk, StrengthClimbing – Elbow Pain – The Ultimate Guide For Rock Climbers, Oct. 05, 2021. (link)[]
  21. Lum, D., Barbosa, T.M., 2019. Brief Review: Effects of Isometric Strength Training on Strength and Dynamic Performance. Int J Sports Med. (link)[]
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8 thoughts on “Dr. Tyler Nelson’s Density Hangs Finger Training for Rock Climbing”

  1. Hello,
    a quick question – in this article on density hangs there are more reps and sets than in the previous article on the “simplest” protocol. Could you elaborate on that, possibly? Awesome blog, BTW, came back to bouldering after two years and this is of high value!

    1. Hi! Thank you for the question – I’d have to get back and review the exact differences between the articles, but in essence, what you need to remember is that tendons like high and slow loading. So the hangs need to be long enough to elicit the sliding effect, improving the tendon quality. Some evidence suggests that you don’t even need to perform the hang in one 30 – 45-second go. Instead, you may perform the exercise Repeater style – the important thing is the time under tension and that you load slowly.

  2. Hi Jędrek,
    Two things:
    It would be great if you tell how many times per week should we do those (during recovery phase off-season)?
    If my max hanging time is 30 seconds how long should I hang during the excersise? Ive checked and there is simply no way that after maxing out for 30 seconds and resting for only 15 seconds I will be able to hang for another 30….

    1. Hi Pawel,
      Thanks for the questions:
      1. I guess 1 – 2 a week would be normal off-season. During the season, if you’re climbing a lot, one long hangboard session per week should be enough, unless you’re doing frequent short sessions with recruitment pulls.
      2. You should probably give yourself some more margin on your load. Measure your 45-second max load and use that instead, so that you’re able to do 2 full reps + 1 rep till failure.

  3. “Hang for 20 – 40 seconds.
    Rest for 10 – 20 seconds – use 1:2 hang to rest ratio.”

    Wouldn’t the rest be 40-80 seconds rest if it is a 1:2 hang to rest ratio? Looks like you wrote a 2:1 hang to rest ratio.

    Huge fan, thanks for all the great material.

    1. Hi Andrew!

      Thanks for the heads up and for your support! Yes, I made a mistake, you should use a 2:1 hang to rest ratio – hang twice as long as you rest. The third rep can get tough!

  4. Hey Jedrzej!

    Ive been slowly reading through all of your articles on training this past week and wanted to ask a quick question! Given how many different protocols youve reviewed, do you have any recommendation for what protocol should be used when?

    1. Hi Alan!
      Thanks for the question! It depends on many factors, e.g., how long you’ve been climbing, have you been recently injured, what are your climbing goals, or are you in or off-season. Also, do you want to train for finger strength or endurance? If for finger strength, should you focus on recruitment or hypertrophy? Or, if you’re trying to improve your endurance, should you go for anaerobic or aerobic.

      People will generally get away with using a random protocol and sticking to it. Still, it might be necessary to delve deeper if you want to optimize your training or break through a climbing plateau without running the unnecessary risk of getting injured. If you’d like to get more information, you can drop me an email.

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