Blog 5 (Endurance part 2)

by Steve Dunning
Posted: 3rd Jun 2011

The Role of Strength.

As mentioned previously endurance means enduring sub maximal climbing. The amount of sub maximal moves you can endure forms a pyramid with the hardest single move you can make at the top and the number of consecutive moves you can make increasing as the difficulty decreases. The base of the pyramid will have the greatest number of moves because they will be at a lower percentage of your maximum strength.The height and shape of the strength-endurance pyramid will depend on the sort of climbing you do; a boulderer will have a tall thin pyramid: the single hardest move he can do will be a lot harder than a route climber so his pyramid will be higher, but because he will have poorly developed aerobic and anaerobic systems the base will be very narrow. 

A route climber in contrast may have a very squat pyramid; well developed aerobic and anaerobic systems will maximise the amount of consecutive sub maximal moves he can do, but his performance will ultimately be limited by his maximum strength.
Given that the number of moves you can do increases as their individual difficulty decreases it would make sense to increase maximum strength to improve endurance.

The main factors influencing the development of strength include: increasing the size of individual muscle fibres, and neural factors including increasing the number of muscle fibres that can be recruited simultaneously and greater fibre twitch synchronicity.
Let's take a look at how these impact on endurance individually:
A climber's maximum bouldering strength is V5 this requires him to recruit 60% of his forearm muscle fibres. At V4 the level of contraction is 50% which is enough to completely occlude his capillaries and cause him to get pumped. He ups his bouldering grade to V6 by increasing his maximum recruitment to 70%. V4 moves now feel easier, but they still need 50% recruitment which is still enough to occlude his capillaries and cause him to get pumped.

If he increases the synchronicity with which his muscle fibres twitch his muscle motor units will become more efficient, requiring fewer to be activated (and therefore fatigued) to move a given load.
Increasing his bouldering grade by increasing the size of his muscle (hypertrophy), V4 moves now need a smaller percentage of his muscle fibres which are now bigger and stronger, however his training has not increased the capillary network which supplies the muscle with blood, or the mitochondria which produce ATP, in effect per cm2 it has actually reduced, this is known as mitochondrial dilution.
In practice increases in strength are a result of multiple factors that are hard to train individually.
Couple sport specific strength training, with aerobic and anaerobic training to increase capillary and mitochondrial density and anaerobic enzymes, and the increases in endurance will be significant, as ultimately your maximum strength determines your sub maximal endurance.

Muscle Fibre Types.

Muscles are made up of individual fibres which contract to cause movement across a joint. These fibres are of 3 types:

Slow Oxidative (SO):
These form about 50% of the total fibres in an average muscle. They possess good endurance characteristics, having a high oxidative capacity and well developed mitochondria and capillaries, however they do not produce as much force as FOG and FG fibres. They are recruited first and are the main fibres used at low intensities.
If your maximum is E1 and you climb a Diff you will mainly be using SO fibres.
Fast Oxidative Glycolytic (FOG):
As intensity or duration increases FOG fibres are recruited. FOG fibres can produce higher force, but have poorer oxidative capacity with a greater glycolytic capacity, making them moderately fatigue resistant.
These are the fibres you rely on in crux sequences, sustained redpoints, and pumpy climbing.
Fast Glycolytic (FG):
These are recruited last and are the strongest but least fatigue resistant.
These are recruited on power moves and sustained crux sequences.

The intensity at which you train (how hard the individual moves are) will determine which muscle fibres you will recruit, and therefore train.

 Arran Deakin


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