The above mentioned explains why it is so important to assign intensity of muscle contraction according to the ability we need to develop. Electromyographic data has shown that in climbers there is a prevalence of fast resistant rather than fast fatigable muscle fibers. The strenuous character of climbing however causes adaptations that improve the functions of both IIa and IIx fibers. To climb hard, we need high levels of strength and muscle endurance. Training only type I and IIa fibers will increase muscle endurance, but may lead to insufficient strength that will make you tired more quickly at cruxes because you will climb at higher %Fm. You may also not be able to generate high enough force to make the moves at the crux even without being tired. Training only IIx muscle fibers will help you deal with cruxes and you will exert less at easier sections (e.g. 70% instead of 80% Fm) but will not increase significantly your endurance and you may often not be able to send at your limit. These different types of training should be distributed according to the climbing level, discipline, and individual characteristics (see Performance factors in sport climbing).

Most of the training should be undertaken at medium and high intensity to gain improvements in both IIa and IIx muscle fibers. How to maintain training within the chosen intensity zone? To do so, we need to measure the forces applied on the holds. However, this will not help during climbing even if the holds at the gym are equipped with force sensors. For example, if you apply the same force on two holds of different size, your forearm muscles will exert more (will act at higher % Fm) on the smaller than on the bigger hold. It is the same when you hang on a small and then on a big rung. The load will be the same in both situations (your weight) but the efforts will differ.

Although climbing is the most effective form of training, it is not enough. Not only fatigue but coordination difficulties are limiting as well. That is why often during climbing you cannot get the needed training workload. To achieve the necessary workload, exercises that reflect the specifics of climbing but are technically simpler should be used. Such exercises can be performed on a hangboard.