Monday, December 29, 2014

Aerobic Endurance Training in Sport Climbing. Capacity (III): Training Methods

Spanish version

I- Overview

1.1. Basic rules

The two methods we are going to discuss have the following rule in common: stay for a long time on the wall, climbing at a low intensity.

1.2. Rhythm

Uniform, steady and adjusted to the previously planned load. You'd be right to guess that the longer the activity, the lower the average pace will be, so that we will move at a slow or very slow speed, stopping just for the time needed to choose the next hold.
Occasionally we will stop for 1-2 seconds to shake our hand a bit, in order not to exceed the set load. But it is not a characteristic of this method to shake off for more than 3 seconds or to stop at a resting point; these are typical of a different method that will be the subject of other entries.

Eva López "self-pointing" the right holds for Capacity training. Picture: Javipec

1.3. Control of the Intensity

This is the most important factor to achieve the desired training effects. When training your capacity it would be ideal to be able to discern what holds and wall angle will allow us to maintain a 1-2 level of pain in the forearms (very mild pump).
  • If we don't comply with that and go beyond level 2, we have to realize that we are not training our capacity anymore, and we should move to a less steep wall or use bigger holds; if necessary, we will even stop at a good jug until we go back to the desired subjective sensation. 
  •  If we need to re-adjust too often, we have to ask ourselves if the set duration is too long, the pause between sets too short or the chose holds/angle aren't ideal at this moment.

1.4. Where to train: How steep, what holds? Route or traverse?...

In general we will seek a wall with the steepness and holds that allow us to limit the forearm pain (level 1-2) and fulfill the programmed volume. With this in mind:
  • If we train on a route that is already set, it should be homogeneous and long. If it's shorter than the desired duration we'll climb and unclimb it as many times as needed without descending to the ground.
  • If the wall is short like in a bouldering gym, and there are no set routes, we will choose our holds as we climb (like playing pointer game alone), trying to move up and down as possible, rather than going laterally all the time.
  • The wall angle and hold size depend on our level. Some examples:
    • an elite climber can work this facet of aerobic endurance on a 130º wall on medium holds (2-phalange deep) and stay there for a long time.
    • a beginner or someone with a lower level will only be able to comply with the volume on slabs and vertical walls with good holds (3-phalange deep), and for a limited time at that. This time issue will be addressed later.

It is important to carefully choose the holds for each content. For Capacity, they will be mostly rounded lip jugs that accommodate 3 phalanges. Photo: JM Climbing holds

II- Method Categories

Attending to the continuity of the action there are two methods:

2.1. Continuous Method

2.1.1. What is it?
It consists on climbing or "staying" on the wall for a prolonged time without descending to the ground. It is the equivalent of continuous running in track and field. Once you step off the floor you do not go down until the time expires. This is the most simple and basic method, with some particularities that will be explained later.

2.1.2. It is recommended for...
- early stages of training for lower and medium level climbers
- a General Mesocycle in the Season for those who want to climb longer routes (more than 15-minute long), onsight 20+ meter long routes, or climb multi-pitch routes
- active recovery sessions
-going back to training after a rest period or an injury, for all levels

2.1.3. Characteristics
From 5 to 45 minutes of continuous climbing.

Andrew Boyd and Sig Isaac on The Opal, Squamish (Canada).
Photo: Rich Weather. Source:

2.2. Discontinuous Methods

2.2.1. What is it?
In these methods the total time is divided into parts called repetitions or bouts, the intensity is low-medium, and the rest time between repetitions are incomplete. It is also known as interval training.

The rationale for this method is that by dividing the time, each segment can be performed at a higher intensity than it would be if the activity was continuous.
The result is that the load is more intensive, and the effects somewhat different to the previous one. Furthermore, the stimulus does not take place only during the climb, but also at the recovery time. In fact, the original method used by long distance runners was based on the idea that the greater influence on cardiovascular performance took place during the pause for recovery, when the heart rate goes from 170-180 bpm down to 120-140 bpm. As readers of this blog already know, we won’t control the intensity by measuring our heart rate; we shall guess our muscle recovery by feeling how pumped our forearms are and how swollen they look, to get an idea of how capable they are to keep on doing medium and low intensity contractions.

Among the panoply of discontinuous methods, we will use the following to develop capacity:

2.2.2. Long Interval Training

The term long (or “extensive”) refers to the typical low intensity-long duration load, by contrast with the high intensity (or intensive) variant that we will explain in the context of a different quality. Recommended for
- early stage of the season for high and very high level climbers.
- Specific Mesocycle in the Season for low and medium level athletes who have already used the continuous method during the general mesocycle, and want to climb long (more than 15 minutes) routes, onsight routes longer than 20 meters or climb multi-pitch routes.
- high and very high level climbers who want to gain or recover capacity during a specific time of the cycle.

The long interval method can be used by medium and high level climbers during the general mesocycle to achieve the capacity that they will need to endure more intensive methods later in the specific mesocycle, and to increase their chance of sending their anaerobic-aerobic endurance/power-endurance projects. Picture: Lee Smith on Bohica, 5.13b, Motherlode, Red River Gorge, Kentucky (USA). Photographer: Nathan Welton. Source: Nathan Welton Photography Characteristics (to be adjusted to level and goals*)
  • Repetition duration: 4-5 to 20 minutes.
  • Recovery duration: 45 seconds to 3 minutes.
  • Total session volume (number of repetitions x repetition length): 8-60 minutes.
 Summing up: 2-8 x 4'-20' : 45"-3' (**)
(**) This reads: perform 2 to 8 repetitions, 4 to 20 minute-long each, and rest 45 seconds to 3 minutes between them (in this case we can assimilate repetitions to sets)

2.2.3. What method to choose, continuous or long interval?

Sometimes our goals and level won't be our only limitations, and other "practical" factors will enter the equation:

If our gym is basically a set of really steep overhangs and/or small holds and we are not able to stay for a long time on such wall, we will opt for the long interval method. But... suppose that even resorting to shorter repetitions our physical sensations are harder than what is expected for this type of training; then it will be long until we can train our capacity for real.

[Paradoxically, the most suitable method to begin training and climbing can't be performed at most of the climbing gyms that we have access to here in Spain]

If we can only stay on the wall for a short time, then either we won't be able to develop our capacity, or we will need to resort to something else... like the intermittent method

When we are lower level climbers our finger flexor muscles lack the required maximum strength… every session can end up being a strength or endurance workout. To mitigate this situation I suggest a variant of the previous methods:

2.2.4. Intermittent Method What is it?
It is a possibility for beginners, and for those who can't go to an "easy enough” wall. It can also be useful after an injury or prolonged resting periods.

The goal is to meet the time requirement, doing brief rests on the floor during which we will stop our watch. It's the equivalent of "jogging" for runners. The workout could be like this:
You decide the total climbing time beforehand (a short one, 3-5 minutes) start your watch and begin climbing. When your forearms pain level is above 2 and it does not go down even by resting at a good jug, you go down to the floor and stop your watch; when the fatigue subsides, you start your watch again and resume climbing. Repeat until you meet the desired time.

III. The million-dollar question: How many sets, repetitions and what pause do I choose?

When it comes to producing concrete numbers, something you would undoubtedly appreciate to start training right now, I remind you that I am not in favor of one size fits all recipes. This not only goes against my vision of training (individualization and specificity), but also is inefficient. It can lead to overtraining, or the opposite: staying below your threshold and getting no effects.

But everyone needs a starting point... so I will propose a basic guide for volume, set duration and recovery duration that is reasonable for each sport level/training experience. Use it, experiment and, from the sensations you get, start tailoring and planning your own training.
Luis Alfonso Félix trying his project "Tres Cromosomos", 9?, Otiñar, Jaén (Spain). Picture: Bernardo Giménez. Fuente: Luis Alfonso Felix facebook page

3.1 Basic guide

3.1.1. Number of repeats and total session volume
In general, we can do longer sets and longer sessions:
  • the more experienced with this kind of training we are
  • if we have more endurance than strength
  • the higher our level is
  • the longer our project is: it's not the same to train for a trip to Rodellar, where we can expect good rests and long climbs, to the Motherlode at Red River Gorge, or to the bouldery routes at Frankenjura, where these contents can even be unnecessary.
  • the longer the type of climbing is: multi-pitch versus sport climbing, onsighting or working a route...
As an example, but without losing sight of the need for individualization, here there are some suggestions for total session volume:

From 8 to 12 minutes (# of repetitions x repetition duration) for lower level or short training experience,
15-30 minutes for medium level,
More than 40 minutes for advanced,
One hour or more for very high level or multi-pitch.

In general, choose the workout time (continuous of discontinuous) and the number of repetitions looking at these two factors:
  • Minutes and number of repetitions that you can maintain the key physical symptoms for.
  • Minutes and number of repetitions that you have used in the previous training cycle.

3.1.2. Measuring Volume: Time vs Movements
Perhaps you prefer to count movements instead of time; then keep in mind that doing a simple traverse on good holds takes 3-5 seconds per movement. Leading a previously set route, you spend up to 5 seconds to clip, and around 3 seconds to chalk up. If there is an anchor every 4 moves, a 20-move route that you already know takes about 2 minutes to climb. By contrast, 5 minutes of easy, not very technical traverse can add up to 100 movements.

To train Capacity, it's best to have access to a wall with relatively easy and homogeneous (in terms of angle, holds, and intensity) routes. PhotoStone Summit Climbing and Fitness Center, Atlanta, USA

In my case, I can only go to a bouldering gym, so leading long indoor routes is not an option. That's in part why I prefer to count minutes, and "self-point" the moves instead of setting a route beforehand; this has its advantages:
  • More accurate measure of volume
  • Focus on volume over intensity
  • Prevent overuse by not repeating the same moves over and over
  • Expand the technical repertoire
  • More finely tune the intensity during each set, instead of ending up unintendedly working a different quality because the route I set was too hard and I wanted to send it anyway.

3.1.3. How long must the rest period be? The recovery dilemma
The rest period between repetitions has to be:

a) Incomplete. It won't allow us to completely recover.
b) Enough. It will allow us to do all the planned repetitions.

In the traditionally called "endurance" sports they use the ratios 1:1, 1:0.5, 1:0.25, meaning the the rest is equal, half or a quarter of the exertion time. Although these formulas are valid when speaking about heart rate recovery (global factors), they are not suitable for factors related to recovery of strength or recovery of the local physiological levels typical of fatigue in climbing. Most of the time we will be able to use shorter pauses for almost every method. In general, the longer the training experience and the higher the level, the shorter the recovery can be tolerated and vice versa. Some examples:
  • For 3 4-minute sets, try a 2' pause if you are of lower-medium level (3x4' easy climbing :2').
  • 3x5' easy climbing :2' for medium level.
  • 7x5' easy climbing :1' for high level.
  • 4x8' easy climbing :90" for high level.
  • 8x5' easy climbing :45" for very high level.
  • 3x20' easy climbing :1' for very high level.

3.2.(*) How to individualize after all this trying?

There's no option but to analyze what of the different combinations of # of repetitions, repetition and rest period is more adequate for our goal: complete the time, monitor the sensations. It can mean going beyond the margins I have proposed, or staying well inside these limits. (Never take the theory verbatim! Take a moment to think about how you really are, and you won't miss).
In any case, I recommend a bit of modesty. Start with "easier" workouts and the least volume. You'll be able to progress from that point. One advantage of being new to a method is that it provides noticeable gains [almost] regardless of the load. We will improve even if we don't use the greatest volume or the shortest pauses. The result is a more sustainable long-term development avoiding unnecessary effort and suffering, and perhaps even skipping some injuries.

V. Summary of Methods for Developing Capacity in Climbing (also known as ARC)

Clic the image to enlarge

In this entry we have glimpsed how to distribute and plan the progression of these methods as the weeks and the training cycle pass, but we will go over this in more detail in the next post.

Why we need to train Local Aerobic Endurance: Let the Numbers Talk
Objectives and Bases for Designing an Endurance Training Program in Sport Climbing
Aerobic Endurance Training in Sport Climbing: Capacity (I). Physiological Adaptations
Aerobic Endurance Training in Sport Climbing: Capacity (II). Training Load Elements: Objectives, Intensity and Volume

Thursday, December 11, 2014

Aerobic Endurance Training in Sport Climbing: Capacity (II). Training Load Elements: Objectives, Intensity and Volume

Versión en español

1. Objectives for Developing Capacity (also known as ARC)

a) Basic objective: Accumulate during the training session many minutes staying on the wall, of actual climbing.
Recommended for the beginning of a cycle, lower and medium level climbers, or those who don't have much experience with training in general.
b) Advanced objective: Total depletion at the end of the sets or the session.
Best for: experienced or high level climbers, or those who have worked the previous objective long enough.

Dani Fuertes resting on La Rubia, 8c+, Villanueva del Rosario, Málaga. Picture: Javipec


We will use a Low intensity. More exactly, up to 25% of maximum grip force (To learn why we choose a % of maximum strength over maximal oxygen consumption or maximum heart rate like they do in other sports, have a look at this entry).

2.1 Why topping at 25% of maximum grip strength?

We will lean on a number of related conclusions:

a) Some authors suggest that 25% of MVC is the highest intesity where the aerobic metabolism is still the main energy source (Fallentin et col., 1993; Byström, 1994; Kimura et col., 2006), and that is the one we want to optimize here (Usaj et col., 2007; Fryer et col., 2014).

b) One of the stimuli that lead to changes in the blood vessels surrounding certain muscle fibers (angiogenesis and arteriogenesis, see previous entry) is the repeated and sustained increase of blood flow in the area (Hudclicka et col., 1992; Prior et col., 1997, Egginton et col., 2001, Hounker et col., 2003) characteristic of aerobic exercise at the aforementioned intensities.

The growth of new blood vessels and the widening of existing ones aid in the development of aerobic endurance. Climber: Tommy Caldwell on Dawn Wall Project, El Capitan, Yosemite National Park, CA (USA). Photo by: Josh Lowell. Source: Climax magazine #20.
One could think that a higher demand on the muscles would increase even more their need for energy and hence blood flow. By the contrary, in isometric contractions maximal blood flow is registered at very low intensities: around 10-25% of MVC. Past this, at 25-40%, the flow does not actually go up, and it even decreases if we go further (Barnes, 1980; Byström and Kilbom, 1990). Let's explain why:
  • On the one hand there has been found a direct association between the intensity of a contraction and blood flow (Sjøgaard, Fagard & Fuel, 1988; Byström & Kilbom, 1990); also between the duration of a contraction and blood flow during the interval between contractions, as well as during recovery after exertion (Byström & Kilbom, 1990; Laughlin et col., 1999).
  • On the other hand, though, the harder the contraction, the more intramuscular pressure (Barnes et col., 1980; Sejersted et col., 1984; Thompson et col., 2007). When it comes to isometric contractions a problem arises: the blood vessels get occluded for several seconds, compromising nutrient exchange. This leads to a buildup of liquid as well. According to some authors, this explains isometric fatigue (Sjøgaard, Fagard & Fuel, 1988; Kalliokoski et col., 2003).
More specifically, tests performed with a dynamometer on the muscles of the forearm have found that the blood occlusion starts at 30% of MVC, and is complete at 50-70% (Barcroft & Miller, 1939; Barnes, 1980; Sjøgaard et col., 1998).

Mich Kemeter at Verdon (Francia). Photo by: Alex Buisse.

2.2 The usual problem... How do we control the intensity during a training session?

From a practical point of view, what kind of holds and what climbing styles do I have to favor?
Looking at what we have already seen we should go for holds that, being on a particular wall, wouldn't represent more than 25% of our maximum grip strength.

a) One possible solution would be to perform a test of maximum climbing time on a certain kind of hold, and looking at the relationship found by Rohmert (1960) and confirmed by successive authors (Allison et col., 2004; Frey & Avin 2010; Looft, 2012) between percentage of MVC during an isometric contraction and maximum duration of such contraction. In short, the higher the intensity the quicker the exhaustion and vice versa. This can also be applied to the number of repetitions/sets in dynamic exercises:
  • An isometric contraction at 10% of MVC can be held for about an hour,
  • A 12% one about 40 minutes,
  • Repeated intermittent contractions at 25% of MVC (10-second contraction / 2-second relaxation) can be sustained for 6-8 minutes.
  • Around 30% the time drops to 2-4 minutes.
(Rohmert 1960, Byström, 1994; Allison et col., 2004; Frey & Avin 2010).

Maximum durations (minutes) for different intesity (%MVC) intermittent contractions (contraction time + relaxation time) and continuous contractions (Byström y Kilbom, 1990)
All these figures have to be taken with a grain of salt, though, because:

i) The participants were untrained people for whom the forearm muscles were not a key performance factor.
ii) There is great variability in low intensity endurance among individuals.
iii) The dyamometer is not considered a specific tool to measure maximum grip strength in climbing (Watss, 2004) neither to assess actual climbing performance. In this regard, we don't know about any climbing-oriented tests that measure maximum time for a wide variety of intensities during real climbing.

Recently López-Rivera, E. (2014) has put forward in her PhD thesis a formula for estimating maximum hang-off duration as a function of edge depth (6-14 mm) and sport level (6b+ to 8c+, n=36), but it is probably valid for higher intensities only (we will go over it in the entries about high intensity endurance) and it remains to be seen its application to actual climbing on holds of similar size to the test ones.
Eva López. Photo by Javipec
b) The common sense approach, a simpler way:
The goal is to find holds and walls of a certain angle that allow us to endure the programmed climbing time at a low intensity:
  • For low-mid level or high volume sessions, we will probably choose the largest holds, those deep enough to fit the entire fingers, with a positive and rounded profile (jugs), on vertical or less than vertical walls. For higher levels the holds could be similar, but the wall more steep or overhanging. Trying holds not so deep is a possibility. Anyway, each climber will have to test it...because as you already know, individualization and control of the training load is key for an effective training.
We will learn to associate low intensity to a set of sensations that can be described as follows.


2.2.2 Sensations related to the Physiological Effects of Capacity Training

Several authors have assessed the validity of subjective scales of perception to control the intensity in different sports (Seyler, S. in Mujika, 2012 [editor]). To develop our Capacity we have to look for and maintain the following sensations:

Local signs at the forearms:
  • Moderate swelling and activation, never stiffness and strong pumping. As we progress in time or sets we may need to shake off every 2-3 moves for 1-2 seconds.
  • Some vasodilation that can translate into "heat", reddening, bulging veins...
  • Progressive "depletion" (according to the objectives for the session).
  • Mild pain. Using the subjective scale from 1 to 5 developed by Binney & MacClure (2006), we should rate at 1 or 2.
Global signs:
  • Light increase in breath and heart rate, etc.
  • Moderate perspiration.
  • As the session progresses, especially at the end of every set, it is normal to notice our movements are "slower", perhaps due to some related factors: a) we start running out of glycogen and use slow-burning fatty acids, b) we need to save energy and the kind of holds we are using allows us to do that, and c) because this way we can relax the free hand a bit longer. When climbing easy parts our hand can stay free for about 0,5 seconds, but it can go up to 1-2 seconds if we climb slower, giving time to the forearm to recover and keep on functioning.
Note: In the future we will publish an entry discussing a proposal for a load control scale in climbing training.

3. Volume

From 10 to 40-60 minutes, attending to the use of continuous or interval methods, our level, our training experience, climbing projects and time of the season, etc.

The next post will expand on the continuous and interval methods, and will offer some guidelines to customize total volume, number of sets, rest pauses, etc.

Why we need to train Local Aerobic Endurance: Let the Numbers Talk
Objectives and Bases for Designing an Endurance Training Program in Sport Climbing
Aerobic Endurance Training in Sport Climbing: Capacity (I). Physiological Adaptations
  • Bechtel, S. Unlearning Endurance Training, website: "Climb Strong"[on-line], Entry from January 21th, 2013. Available at:
  • Guyton, A., and Hall, J. (2006). Textbook of medical physiology, 11th.
  • MacLeod, D (2010). 9 out of 10 climbers make the same mistakes: navigation through the maze of advice for the self-coached climber. Rare Breed Productions. (pp 85-89).
  • Randall, T Tricks of the endurance training trade, website: "Tom Randall Climbing"[online], Entry from July 9th, 2012. Available at:
  • Wilmore, JH and Costill, DL (2004). Physiology of Sport and Exercise. Human Kinetics.
  • Allison, B., Desai, A., Murphy, R., & Sarwary, R. M. (2004). Human potential of applying static force as measured by grip strength: Validation of Rohmert’s formula (Doctoral dissertation, Thesis. San Jose State University).
  • Barcroft H, and Millen JLE (1939) The blood flow through muscle during sustained contraction. J Physiol (Lond) 97:17--3
  • Barnes WS. (1980). The relationship between maximum isometric strength and intramuscular circulatory occlusion. Ergonomics 23: 351–357.
  • Binney, D, and McClure, S (2006). Aerobic and anaerobic power: Power endurance. Climb, 26, 64 66.
  • Byström, SEG, and Kilbom, Å (1990). Physiological response in the forearm during and after isometric intermittent handgrip. European journal of applied physiology and occupational physiology, 60(6), 457-466. 
  • Byström, S (1994). Estimation of aerobic and anaerobic metabolism in isometric forearm exercise. Upsala journal of medical sciences, 99(1), 51-62.
  • Fallentin, N, Jørgensen, K, and Simonsen, EB (1993). Motor unit recruitment during prolonged isometric contractions. European journal of applied physiology and occupational physiology, 67(4), 335-341.
  • Frey Law, L. A., & Avin, K. G. (2010). Endurance time is joint-specific: a modelling and meta-analysis investigation. Ergonomics, 53(1), 109-129. 
  • Fryer, S., Stoner, L., Scarrott, C., Lucero, A., Witter, T., Love, R., ...and Draper, N. (2014)Forearm oxygenation and blood flow kinetics during a sustained contraction in multiple ability groups of rock climbers. Journal of sports sciences, (ahead-of-print), 1-9.
  • Hounker M, Schmid A, Schmidt-Trucksass A, Grathwohl D, and Keul J (2003). Size and blood flow of central and peripheral arteries in highly trained able-bodied and disabled athletes. J Appl Physiol 95: 685–691.
  • Kimura, N, Hamaoka, T, Kurosawa, Y, and Katsumura, T (2006). Contribution of intramuscular oxidative metabolism to total ATP production during forearm isometric exercise at varying intensities. TheTohoku journal of experimental medicine, 208(4), 307-320.  
  • Looft, JM (2012). Modeling and validating joint based muscle fatigue due to isometric static and intermittent tasks.
  • López-Rivera, E (2014): Efectos de Diferentes Métodos de Entrenamiento de Fuerza y Resistencia de Agarre en Escaladores Deportivos de distintos Niveles (Tesis Doctoral). Programa de Doctorado en Rendimiento Deportivo, Universidad de Castilla-La Mancha, Toledo, España.
  • Rohmert, W, 1960. Determination of the recovery pause for static work of man. Internationale Zeitschrift Fur Angewandte Physiologie, Einschliesslich Arbeitsphysiologie 18, 123-164.
  • Seiler, S  (2012). Training Intensity Distribution, Chapter 4. En Mujika, I. (editor), Endurance Training (pág. 31-39). Bizkaia. I. Mujika.
  • Sjøgaard, G, Savard, G, and Juel, C (1988). Muscle blood flow during isometric activity and its relation to muscle fatigue. European journal of applied physiology and occupational physiology, 57(3), 327-335.
  • Sejersted OM, Hargens AR, Kardel KR, Blom P, Jensen O, and Hermansen L. (1984). Intramuscular fluid pressure during isometric contraction of human skeletal muscle. J Appl Physiol 56: 287–295
  • Thompson, B. C., Fadia, T., Pincivero, D. M., and Scheuermann, B. W. (2007). Forearm blood flow responses to fatiguing isometric contractions in women and men. American Journal of Physiology-Heart and Circulatory Physiology, 293(1), H805-H812.
  • Kalliokoski, K. K., Laaksonen, M. S., Takala, T. O., Knuuti, J., and Nuutila, P. (2003). Muscle oxygen extraction and perfusion heterogeneity during continuous and intermittent static exercise. Journal of Applied Physiology, 94(3), 953-958.
  • Ušaj, A., Jereb, B., Robi, P., and von Duvillard, S. P. (2007). The influence of strength-endurance training on the oxygenation of isometrically contracted forearm muscles. European journal of applied physiology, 100(6), 685-692.
  • Watts, P. B. (2004). Physiology of difficult rock climbing. European journal of applied physiology, 91(4), 361-372.

Thursday, November 13, 2014

Aerobic Endurance Training in Sport Climbing: Capacity (I). Physiological Adaptations

Versión en español

Up to 35 minutes to climb a previously tried route.
In occasions, up to 1 hour to onsight a route.
Most sport climbing routes take between 8 and 25 minutes.
(Data from a study of my own)

Eva López on Fish Eye, 8c. Oliana. Picture by Vojtech Vrzba
As it was noted in the previous entry, rather than training some particular physical quality, it would be more precise to speak of specific physiological effects from now on. As a reminder, here there are the different aspects or objectives related to local aerobic endurance:
  • Capacity (enduring long, low intensity climbs), also known as ARC
  • Efficiency or Steady State (negotiating moderate intensity-medium duration sections).
  • Quick Recovery.
 In this entry we will go over the goals and aspects related to what can be called the Training Zone #1: Capacity. The others will be the subject of the next two.
A Definition of Capacity
We can begin by stating that it is the quality that allows us to sustain a long climb (more than 15 minutes) with minimum fatigue. It can be described as the ability to keep our energy and strength, be it because we spend some of our substrates (energy sources) more slowly or we replenish them faster, or because our muscle efficiency at low intensity improves as a result of factors that we are going to learn.

Some activities that demand capacity are multi-pitch routes, onsighting long or technical routes, or sorting out the moves of a hard route.

Beware! Acknowledging its importance does not mean it has to be the only training goal for those activities. It would be like saying that a marathon runner just needs to run, not very fast, for a couple of hours...

In the English-speaking world it is also known as ARC (Aerobic Energy Restoration and Capillarity), from Goddard and Neumann (1993) for reasons that will become clear (**see recommended readings below).

If you are still unclear of the impact of this aspect on your climbs, I suggest you time your next try to a route that you want to climb. If you use more than 15 minutes to do it, or to sort out the moves, or to onsight it, it’s possible you will find useful the rest of this blog post.
Jose Luis Palao "Primo" on "La Planta de Shiva", L1, Villanueva del Rosario, Málaga.
Phto by Javipec. Source: Javipec Photo.
Physiological Changes in response to Capacity Training

At the physiological level, according to the duration, intensity and particularities of the effort (local aerobic endurance of the small muscles in the forearm), the development of Capacity in sport climbing can imply modest central (cardiovascular) development, but the bulk of the adaptations are both peripheral:

They allow for a faster and optimal oxygen supply to the muscle, as well as a better removal, recycling and oxidation of the products of muscle metabolism (*see glossary below) that have an influence on fatigue, like Pi, ADP, AMP, H+,NH4+, etc. These are the main ones:

a) Increased capillarization at the oxidative or slow twitch fibers (type I or ST) due to the creation of new blood vessels (angiogenesis) as well as to the growth in diameter or caliber (arteriogenesis) (Anderson and Henriksson, 1977; Mizumo et col., 1990; Ferguson and Brown, 1997; Laughlin et col, 2006, 2008; Thompson et col., 2014).

These adaptations are among the most important for the development of endurance in climbing according to several authors (MacLeod et col.,2007, Phillipe et col., 2011, Thompson et col., 2014 and Fryer et col., 2014). The explanation lies on the particularities of climbing:

-The big contrast between the long, intermittent, high intensity isometric contractions needed for successive small, difficult holds (8-15 seconds) and the short time between holds (less than 0,5 seconds, 3 seconds if we are clipping or up to 5 second shakes in a good rest) (López, E., 2014, Doctoral Thesis).
- The mixing of high intensity sections among medium and low intensity ones.
- The succession of movement and static positions (rest stops, clippings...) where the climber tries to recover from fatigue.
Lauren Lee making the second ascent of Master Blaster 5.13+, Zion. Photo: Sonie Trotter. Source: Gripped Canada's Climbing Magazine facebook page
Some authors think that improved capillarization can positively influence oxygen supply and metabolite removal, resulting in faster recovery and the possibility of more effectively training power endurance (anaerobic endurance) later in the training program; this will be addressed in a future blog post. These statements are supported by the significant positive correlation between # of capillaries per square millimeter and the number of repetitions at 70% of 1RM (Terzis et col., 2008), performance at tests with a duration of 30”-3’ (Iaia et col., 2011), recovery when doing short (40”) pauses between high intensity exercises (Tesch and Wright, 1983), and rate of recovery after 50 repetitions of leg extensions (Wright et col., 1983).
b) Elevated threshold for sympathetic activation that promotes vasodilation after and during isometric contractions, and improves tissue perfusion (Sinoway et col., 1987; Ferguson and Brown, 1997, Fryer et col., 2014). During muscle action, the buildup of some metabolites excites nerve endings that induce an activation of the sympathetic system (Sinoway, 1996; Mostoufi, 1998) that can affect efficiency it this response is too strong (this tends to happen when you are undertrained). It’s likely that this nerve excitation is reduced in climbers due to this increased threshold, but also because of lower hormone secretion at a given intensity, better tissue perfusion (Ferguson and Brown, 1997; Fryer et col., 2014 ) and, as we will learn later, an optimized aerobic metabolism.


2.1) Morphological adaptations
These consist of structural changes in muscle fibers:

a) Increase in the mitochondrial* content of skeletal muscle, i. e., # of mitochondria per mm2 of fiber (Hoppeler et col., 1985; Befroy et col., 2008).
Muscle fibre structure.
b) Development of Slow twitch (type I or ST) fibers, both relative to fast fibers (Costill et col., 1976) in size (hypertrophy) (Mitchell et col., 2012) or in fiber recruitment pattern (Hawley and Stepto, 2001; Arnold y col., 2014). These fibers are more resistant to fatigue, which confers them a vital role not only for maintaining strength at lower intensity for a long time, but also for recovering between intense efforts by helping “recycle” the lactate produced by their neighboring fast twitch (type II) fibers. This takes place at resting points, but also while clipping (about 3 seconds), and even when we release a hold for more than one second; if we are bouldering, it helps recovering between tries. It’s worth noting, though, that these latter adaptations are better achieved through the other two local aerobic endurance goals (efficiency and recovery ability).

Rannveig Aamodt, Red River Gorge,  Kentucky. Picture by Carter Agency. Source:
c) Increased muscle energy substrates, in particular glycogen* and muscle triglycerides (Greiwe et col., 1999; Burgomaster et col., 2005; Burke 2010). One cause of fatigue during prolonged exertion is the depletion of glycogen deposits. On a related note, it has been observed that a big store of one energy source can make cells more reliant on said source (mass action effect); this adaptation can be important for multi-pitch and big wall climbers.

2.2) Metabolic adaptations
Related to the improvement in glycogen and fat aerobic metabolism (especially in slow twitch fibers) that offsets the activation of the anaerobic pathway (lactate production) (Holloszy and Coyle, 1984); also to an increase in lactate clearance (lactate is continuously formed in some tissues like muscle and released from them, and its buildup is mitigated by lactate oxidation).

a) Increased oxidative enzyme* levels; these are involved in the aerobic metabolism (Krebs cycle and electron transport) (Henrikson and Hickner 1993; Burgomaster et col., 2005), especially in type I (slow) fibers and type IIa or mixed fibers (that play a role in anaerobic endurance or power endurance). This elevation, together with greater vasodilation and capillary density (tissue perfusion) has been shown to be very important for isometric grip endurance (Fryer et col., 2014).

b) Increase in lactate transport proteins (MCT1) that move lactate in and out of muscle fibers in order to oxidize it (lactate shuttle) (McCullagh et col., 1997; Everstsen et col., 2001, Thomson et col., 2005; Gladden 2008). This is part of the already mentioned lactate clearance.

Alex Honnold climbing in Devil's Bay, NewFoundland. Photo: North Face. Source: Gripped Canada's Climbing magazine facebook page
c) Increase in glucose transport proteins (GLUT4) that move glucose into muscle fibers to quickly use it (García Manso et col., 2006). In combination with the promotion of glycogen synthase (an enzyme involved in glycogen creation), it makes for a faster replenishment of glycogen when depleted after a high-volume or intense workout (Ryder et col., 1999).

d) Elevated fat oxidation at intensities that previously would have required glycogen (greater reliance on fat oxidation), resulting in “savings of the latter (Kiens et col., 1993; Hawley et col., 1998; Burke et col., 2001). As we already know we need our glycogen for the hardest sections, because fat metabolism is not fast enough to cover the rate of energy consumption that are demanded (Brooks and Mercier, 1994); fat metabolism is ideal for long, low intensity tasks.

Ok, this is all fine, but by now some of you will be growing impatient, just wondering: How do I have to train to achieve these effects? Well, this will be the topic of the next two entries (Load Variables, Training Methods and Planning), soon to be published.


ATP or adenosine triphosphate: It is the foremost energy transporter in the body. It acts as a kind of “energy currency”, transferring energy to other molecules by losing a phosphate group (adenosine diphosphate or ADP). ADP in turn can accept chemical energy in the form of a phosphate group to transform back into ATP (oxidative phosphorylation). Structurally it’s a nucleotide formed by adenosine (one adenine molecule bonded to a five-carbon sugar: ribose) combined with three inorganic phosphates (Pi) through high-energy bonds; that’s why breaking those bonds releases a big amount of energy.

Enzymes: Proteins that facilitate decomposition of chemicals (carbohydrates, fats and proteins) to obtain energy for bodily functions like muscle contraction.

Glycogen: The way the body stores its glucose. Structurally is a glucose polysaccharide stored in the liver and muscles until it is needed. The process by which it gets degraded (oxidized) to obtain energy is called glycolysis. The inverse, when it is resynthesized from several glucose molecules is called glycogenesis.

H+: Hydrogen protons, product of ATP hydrolysis. Its buildup along with other metabolites’ is related to one type of muscle fatigue. It usually accretes when there is a high power demand (energy per time unit), when the aerobic metabolic pathway is underdeveloped or when the energy substrates are depleted.

Mitochondria: It’s the organelle responsible for energy production inside the cell using the aerobic pathway (aerobic oxidative metabolism).

Metabolism: Set of physical and chemical processes that take place in the body with two functions: a) obtaining energy from food and storing it in ATP form and b) producing compounds and creating or replacing structures. When the generation of ATP (energy acquisition) is done without using oxygen it is called anaerobic metabolism; when oxygen is used it is aerobic or oxidative metabolism.

NH4+: Ammonium. Product from the metabolism of phosphagens (ATP and phosphocreatine).


Why we need to train Local Aerobic Endurance: Let the Numbers Talk
Objectives and Bases for Designing an Endurance Training Program in Sport Climbing

  • Goddard, D., and Neumann, U. (1993). Performance rock climbing. Stackpole Books. (pp. 105-106; 121-124)
  • MacLeod, D. (2010). 9 out of 10 climbers make the same mistakes: navigation through the maze of advice for the self-coached climber. Rare Breed Productions. (pp. 87-88)
  • McArdle, W., Katch, F. I., y Katch, V. L. (1990). Exercise Physiology: Nutrition, Energy and Human Performance. LWW. (chapters 6, 7, 15, 16, 18)
  • Randall, T. Tricks of the endurance training trade, website "Tom Randall Climbing" Entry from July 9th, 2012. Available at:
  • Wilmore, J. H., and Costill, D. L. (2004). Physiology of Sport and Exercise. Human Kinetics. (chapters 4, 5, 6 and 9)

  • Allison, B., Desai, A., Murphy, R., and Sarwary, R.M. (2004). Human potential of applying static force as measured by grip strength: Validation of Rohmert´s formula. San Jose University
  • Andersen, P., and Henriksson, J. (1977). Capillary supply of the quadriceps femoris muscle of man: adaptive response to exercise. The Journal of physiology, 270(3), 677-690.
  • Arnold, A. S., Gill, J., Christe, M., Ruiz, R., McGuirk, S., St-Pierre, J., ... & Handschin, C. (2014). Morphological and functional remodelling of the neuromuscular junction by skeletal muscle PGC-1α. Nature communications, 5.
  • Brooks and Mercier, J. (1994). Balance of carbohydrate and lipid utilization during exercise: the" crossover" concept. Journal of Applied Physiology, 76, 2253-2253.
  • Burgomaster, K. A., Hughes, S. C., Heigenhauser, G. J., Bradwell, S. N., and Gibala, M. J. (2005). Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans. Journal of applied physiology, 98(6), 1985-1990.
  • Costill, D. L., Daniels, J., Evans, W., Fink, W., Krahenbuhl, G., and Saltin, B. (1976). Skeletal muscle enzymes and fiber composition in male and female track athletes. J Appl Physiol, 40(2), 149-154.
  • Befroy, D. E., Petersen, K. F., Dufour, S., Mason, G. F., Rothman, D. L., and Shulman, G. I. (2008). Increased substrate oxidation and mitochondrial uncoupling in skeletal muscle of endurance-trained individuals. Proceedings of the National Academy of Sciences, 105(43), 16701-16706.
  • Evertsen, F., Medbø, J. I., and Bonen, A. (2001). Effect of training intensity on muscle lactate transporters and lactate threshold of cross‐country skiers. Acta Physiologica Scandinavica, 173(2), 195-205.
  • Ferguson, R. A., & Brown, M. D. (1997). Arterial blood pressure and forearm vascular conductance responses to sustained and rhythmic isometric exercise and arterial occlusion in trained rock climbers and untrained sedentary subjects. European journal of applied physiology and occupational physiology, 76(2), 174-180.
  • Frey Law, L. A., and Avin, K. G. (2010). Endurance time is joint-specific: a modelling and meta-analysis investigation. Ergonomics, 53(1), 109-129.
  • Fryer, S., Stoner, L., Scarrott, C., Lucero, A., Witter, T., Love, R., ...and Draper, N. (2014). Forearm oxygenation and blood flow kinetics during a sustained contraction in multiple ability groups of rock climbers. Journal of sports sciences, (ahead-of-print), 1-9.
  • García Manso, JM; Vitoria Ortiz, M; Navarro Valdivielso, F; Legido Arce, JC (2006). La resistencia desde la óptica de las ciencias aplicadas al entrenamiento deportivo. Grada Sport Books.
  • Gladden, L. B. (2008). A lactatic perspective on metabolism. Medicine and science in sports and exercise, 40(3), 477-485.
  • Goddard, D., and Neumann, U. (1993). Performance rock climbing. Stackpole Books.
  • Greiwe, J. S., Hickner, R. C., Hansen, P. A., Racette, S. B., Chen, M. M., and Holloszy, J. O. (1999). Effects of endurance exercise training on muscle glycogen accumulation in humans. Journal of Applied Physiology, 87(1), 222-226.
  • Hawley, J. A., Brouns, F., and Jeukendrup, A. (1998). Strategies to enhance fat utilisation during exercise. Sports Medicine, 25(4), 241-257.
  • Hawley, J. A., & Stepto, N. K. (2001). Adaptations to training in endurance cyclists. Sports Medicine, 31(7), 511-520.
  • Holloszy, J. O., and Coyle, E. F. (1984). Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. Journal of applied physiology, 56(4), 831-838.
  • Hoppeler H., Howald H., Conley K., Lindstedt S.L., Claasen H., Vock P. and Weibel E.R. (1985). Endurance training in humans: aerobic capacity and structure of skeletal muscle. J Appl Physiol; 59(2):320-7.
  • Iaia, F. M., Perez-Gomez, J., Thomassen, M., Nordsborg, N. B., Hellsten, Y., and Bangsbo, J. (2011). Relationship between performance at different exercise intensities and skeletal muscle characteristics. Journal of applied physiology, 110(6), 1555-1563.
  • Karpp, J.R. (2000). Interval Training for the Fitness Professional. National Strength & Conditioning Association, 4(22), 64–69
  • Kiens, B., Essen-Gustavsson, B., Christensen, N. J., and Saltin, B. (1993). Skeletal muscle substrate utilization during submaximal exercise in man: effect of endurance training. The Journal of Physiology, 469(1), 459-478.
  • Laughlin, M. H., Cook, J. D., Tremble, R., Ingram, D., Colleran, P. N., and Turk, J. R. (2006). Exercise training produces nonuniform increases in arteriolar density of rat soleus and gastrocnemius muscle. Microcirculation, 13(3), 175-186.
  • López-Rivera, E. (2014): Efectos de Diferentes Métodos de Entrenamiento de Fuerza y Resistencia de Agarre en Escaladores Deportivos de distintos Niveles (Tesis Doctoral).  Programa de Doctorado en Rendimiento Deportivo, Universidad de Castilla-La Mancha, Toledo, España.
  • MacLeod, D., Sutherland, D. L., Buntin, L., Whitaker, A., Aitchison, T., Watt, I., ... and Grant, S. (2007). Physiological determinants of climbing-specific finger endurance and sport rock climbing performance. Journal of sports sciences, 25(12), 1433-1443.
  • Mitchell, C. J., Churchward-Venne, T. A., West, D. W., Burd, N. A., Breen, L., Baker, S. K., and Phillips, S. M. (2012). Resistance exercise load does not determine training-mediated hypertrophic gains in young men. Journal of applied physiology, 113(1), 71-77.
  • Mostoufi-Moab, S., Widmaier, E. J., Cornett, J. A., Gray, K., and Sinoway, L. I. (1998). Forearm training reduces the exercise pressor reflex during ischemic rhythmic handgrip. Journal of applied physiology, 84(1), 277-283.
  • Philippe, M., Wegst, D., Müller, T., Raschner, C., & Burtscher, M. (2012). Climbing-specific finger flexor performance and forearm muscle oxygenation in elite male and female sport climbers. European journal of applied physiology, 112(8), 2839-2847.
  • Ryder J. W., Kawano Y., Galuska, D., Fahlman R., Wallberg-Henriksson H.T., Charron M. J., and Zierath J. R. (1999). Postexercise glucose uptake and glycogen synthesis in skeletal muscle from GLUT4-deficient mice. The FASEB Journal, 13(15), 2246-2256.
  • Sinoway, L., Shenberger, J., Leaman, G., Zelis, R., Gray, K., Baily, R., and Leuenberger, U. (1996). Forearm training attenuates sympathetic responses to prolonged rhythmic forearm exercise. Journal of Applied Physiology, 81(4), 1778-1784.
  • Stanula, A., Roczniok, R., Maszczyk, A., Pietraszewski, P., and Zając, A. (2014). Te role of aerobic capacity in high-intensity intermittent efforts in ice-hockey. Biology of Sport, 31(3), 193.
  • Terzis, G., Spengos, K., Manta, P., Sarris, N., and Georgiadis, G. (2008). Fiber type composition and capillary density in relation to submaximal number of repetitions in resistance exercise. The Journal of Strength & Conditioning Research, 22(3), 845-850.
  • Tesch P., Wright J.E. (1983). Recovery from short term intense exercise; its relation to capillary supply and blood lactate concentration. Eur. J. Appl. Physiol.;52:98-103
  • Thomas, C., Perrey, S., Lambert, K., Hugon, G., Mornet, D., and Mercier, J. (2005). Monocarboxylate transporters, blood lactate removal after supramaximal exercise, and fatigue indexes in humans. Journal of Applied Physiology, 98(3), 804-809
  • Thompson, E. B., Farrow, L., Hunt, J. E., Lewis, M. P., and Ferguson, R. A. (2014). Brachial artery characteristics and micro-vascular filtration capacity in rock climbers. European journal of sport science, (ahead-of-print), 1-9. Published online: 28 Jul 2014