However, regarding the tris part, the muscle is already pumped subliminally through it being a secondary muscle group when working out chest. Therefore IMO, a more effective split, for example, would be chest/bis since you are initiating mental focus twice as opposed to once. if that makes any sence? In order to substantiate my aforementioned point regarding a mind-muscle connection I put forward the idea of the disabled: Taken out of context in order to further develop a holistic view, we analyse a blind man.
Since this person has lost one of his senses he is much more dependant on other senses such as touch for example. Therefore the mind muscle connection has created strong links between the brain/nervous system and nerves in his fingers (braille) to ensure the human flys (recalling upon both the fight or flight theory and Darwin's natural selection - and also a point that Tread-m touched upon in his most recent post, the Causality Paradigm - Cause and Effect ).
Now, if we put this back into context, a bodybuilder would aim to develop/enhance their mind-muscle connection to further the efficiency of their muscle growth, as it has proven to be beneficial through the simple analytical awareness of the target muscle group and the overall objective, thus creating a synergistic harmonious benefit. Also, neurological changes – ultimately the nervous system is responsible for ‘recruiting’ muscle fibers.
In simple terms the nervous system stimulates a muscle to contract by sending down electrical impulses towards the muscle. Scientists can measure the ability of the nervous system to stimulate muscle by measuring its electrical activity. In order to optimise the mind-muscle connection, more myelin must be created (Myelin is the insulation for nerve fibres - think of this as the rubber which insulates your household electrical appliances) - thus, the more myelin, the stronger and more accurate the electrical activity will be.
Every human skill, regardless of which activity it is (for example, playing soccer, playing a musical instrument, running in a 100 metre sprint) is created by thousands chains of nerve fibres carrying an electrical pulse - resulting in a signal being transmitted from a source (CNS - Central Nervous System)to the muscles required to perform a specific task. The role of myelin is to embrace and wrap around the nerves carrying the signal in order to ensure that the signal level is efficient - thus reducing the amount of electrical impulse being leaked outside of the intended destination.
Thus, upon practising (through bodybuilding repetitions, for example) our neurological circuits are continuously firing and through repetitions, our brain signals send messages to ensure each correctly fired signal's nerve is insulated more and more - (think of this as if the more myelin there is insulating your nerve fibres, the more efficient you are at performing that specific movement). Myelin is very important for many reasons. Everyone can produce it - and it is produced more efficiently during our childhood years (which is why it is considered easier to pick up a skill/talent in our youth than in our senior years).
Additionally, its indiscriminate - and growth can be a result of both mental and physical actions. Myelin is therefore an inhibitor of skill - whereby skill is defined as "a cellular insulation that wraps neural circuits and that grows in response to certain signals" (Coyle, D. , 2009) - thus, through the analysis of the aforementioned quote, the more time and energy you administer with achieving a certain skill-set - the more efficient and effective you become at it (substantiated by the common phrase practise makes perfect).