Personal Trainer Certification Education: Exercise Science Review
EXERCISE SCIENCE EDUCATION: Training
Adaptations to the Nervous System
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The type of neural adaptation which occurs depends upon the stimulus placed on it. This is what training is
– the body adapting to a new stimulus. In fact, the first results obtained from a new training stimulus are
neural adaptations. Early strength gains (within the first few weeks) from resistance training are not due to
increases in muscle mass. The body adapts to a new stimulus with more efficient movement or enhanced
ability to move greater loads due to the improved communication between the nervous and musculoskeletal
systems, if the training stimulus has been correctly applied. This method of adaptation is called the Law of
Facilitation. The law of facilitation states that when an impulse passes through a given set of neurons to the
exclusion of others, it will tend to do so again, and each time it transverses this path, the resistance will be
smaller. The body will then adapt and be able to respond with greater ease and increasing ability.
Trainers must understand how an individual learns. Anytime an individual learns something new, several
mistakes are often made. This is normal and called the cognitive phase of learning. In this phase the
individual must think about the action, requiring the involvement of the central nervous system. Movement
is usually gross and uncoordinated and relies on visual and verbal cues. However, with continued practice,
less errors or mistakes are made. This is called the associative phase of learn- ing. There is greater
consistency in replicating the movement while less visual cues and greater proprioception are required.
Proprioception is an awareness of one’s position in space. Ultimately, with continued (quality) practice, an
individual will perform movements “flawlessly.” This is called the autonomic phase of learning. The skill
is now performed automatically. Conscious thought is not required, which is the ultimate goal in
performing efficient movement. This is known as the Fitts and Posner Three-Stage Model of Motor
What does this mean? The more an action is repeated, the more efficient the brain becomes in
communicating with the muscles, and the mes- sage between the brain (central nervous system) and
muscles (musculoskeletal system) is enhanced. Personal trainers should view this as the process of learning
technique. If a person learns poor technique and repeats it continually, the client will only be good at poor
technique. That’s why teaching proper form from the beginning is the key. Trainers must not only teach
good form, but the importance of good form. Proper form (technique) leads to the development of proper
motor skills and proper motor skills lead to mechanical efficiency.
The more appropriately the nervous system is challenged, the better the overall adaptation. In other words,
exercises which challenge overall balance and coordination are going to allow for better neuromuscular
adaptation and improved bodily control. All other movements should see improvement. Movement starts
with the brain. If a trainer is able to have their client “realize” and “become conscious” of what
is happening, this will lead to more effective and efficient exercise execution and result in an increase in
performance. This is no easy task. This is your challenge.
Lastly, when talking about neuromuscular development, we must mention power. Remember, power is the
rate that work is performed and power has a HUGE neuromuscular component. What is going to determine
how fast and powerful someone is able to move? A major factor is how quickly their brain can tell their
muscles to fire.
What is Mechanical Efficiency?
The job of the personal fitness trainer is defined as maximizing your client’s performance safely and
efficiently. It was later pointed out that Maximum Performance will be determined by Mechanical and
In physics, mechanical efficiency measures the efficiency of a machine. Mechanical efficiency is a ratio of
the work output to work input.
Mechanical Efficiency = Work Output
So if a machine is 100% efficient, all the work going into it would be transferred to work out- put (an “ideal
machine”). Well, there are no ideal machines and the human body is far from ideal. That said, we want to
be as efficient as possible. We don’t want “wasted” energy.