That is the relationship between the intense activation of the nervous system and enhanced fast-twitch muscle fibre recruitment.
For instance, as a result of their training body builders have a tendency to have relatively more type IIa muscle fibres which allow for forceful, but relatively slow movements.
Whereas sprinters, as a result of their training, may have a larger amount of type IIb muscle fibres allowing for forceful, and relatively fast movements.
Generally, the aim of complex training is to stimulate the athlete to develop more type IIb muscle fibres.
[9]In the context of rock climbing, and an isometric exercise preceding a plyometric one, Steve Maisch considers that one of the training goals of complex training is to operate at a level of fatigue thereby encouraging the body to learn to recruit from a wider range of muscle fibres in order to be able to apply the appropriate power.
Thus, over a period of training, increasing the system strength and power output of the athlete as their body has learnt to recruit a larger number of muscle fibres.
‘The way complex training works, in theory, is that the isometric part of the exercise will cause the muscle fibers which are typically recruited for a given movement to become fatigued.
The end result is that more muscle fibers are recruited when performing a particular movement enabling you to jump higher or do a more difficult climbing move.’ [10]Studies on the effectiveness of complex training often last between 4 and 12 weeks and measure such abilities as vertical jump height and sprinting speed.
It is designed to both utilise the PAP effect from the first exercise whilst also further increasing neural activation and muscle fibre recruitment.
Complex training can be used by combat athletes such as boxers and martial artists in order to improve their performance.
Because the intense activation of the nervous system and correspondent recruitment of muscle fibres which occurred in conjunction with the heavy lift has allowed the person to perform more powerful movements, and the weight therefore feels relatively lighter.
Complex training may be utilised by rock climbers in order to develop their ability to apply power quickly either in terms of dynamic movement or in the securing of holds.