Dr. Tyler Nelson’s Density Hangs
- Dr. Tyler Nelson’s Density Hangs – Introduction
- Dr. Tyler Nelson – at the cutting edge of rock climbing science
- What are Density Hangs?
- Density Hangs protocol details
- Density Hangs protocol summary table
- Density Hangs protocol remarks
- Understanding Density Hangs – basic tendon anatomy
- Density Hangs for injury prevention – tendon stiffness and the collagen sliding effect
- Density Hangs in tendinopathy treatment – the concept of stress shielding
- Repeaters vs. Density Hangs
- Density Hangs – summary
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 . 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 .
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 .
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 . 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 . 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
- Choose 2 - 3 hold positions for training. Consider:
- Half crimp
- Open hand
- Pinch (you may use pinch blocks)
- For each position, choose a hold on which you can hang with two arms between 20 and 45 seconds, ideally without added load.
- 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.
- Rest 3 - 5 minutes
- Repeat the set for the same hold position or move to the next position.
- 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.
|Hang test time [s]||20 - 45|
|MVC-7 load||55 - 85%|
|Sets||4 - 9|
|Hangs/set||2 - 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
- Focus on slow static loading until muscular failure
- 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 .
- 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.
- 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.
- 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.
- 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 . Fibers are bundled into cable-like structures, the fascicles, encapsulated by the endotenon — a cuff of connective tissue providing vascular supply .
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 . 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 . 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 .
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.
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 . 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 . 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 . 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 . 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.
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