Central Nervous System & Lifting Weights

Strength begins here.

Many things contribute to muscular power, and even though muscle size is the most obvious, there are other factors that are even more important. Possibly the most critical is the central nervous system, which is responsible for the transmission of impulses to your muscles. The stress placed on the CNS is directly proportional to the load you are attempting to lift, so the heavier you train, the greater the CNS response. Before beginning any training program, consult your physician.


Motor Unit Recruitment

A motor unit is a special unit within your muscles that innervates, or activates, a number of muscle fibers. Fibers contract, generating force in response to stress, so the motor unit signals the fibers to contract, which is where your muscular power comes from. Research from the Soviet Institute of Physical Culture has shown that training with loads in excess of 90 percent of your one repetition maximum is the best way to increase the number of motor units activated, as well as trigger a response of anabolic hormones from your endocrine system.


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Rate Coding

Not only do the number of motor units have an impact on your ability to generate strength, but the rate at which you activate motor units plays a role as well. This is referred to as rate coding, and the faster you activate motor units, the quicker you generate strength. Athletes with high levels of rate coding are often referred to as explosive, and this is a quality demanded by many sports, from track to mixed martial arts. This quality is best trained by a combination of lifting heavy weights and moving slightly lighter weights extremely quickly. Train with either 90 percent or more of your one-repetition maximum, or at least 80 percent of your one-repetition maximum and try and move the weight as quickly as you can without sacrificing technique.



In lifting, there are two types of coordination. Inter-muscular coordination, which is your ability to coordinate multiple muscles in a skill-related task, such as any lift, and intra-muscular coordination, or your ability to coordinate the firing patterns of your individual fibers within a muscle to perform in an optimal manner, or at least the degree to which the fibers are activated at your command. The greater degree of both that you possess, the more you can lift, as you are not only getting more force out of each muscle, but a greater total force output as your muscles work together more efficiently. This also requires training at more than 90 percent of your one-repetition maximum.



While motor units fire based upon training load, and fibers are recruited on an as-needed basis, elite lifters show not only a greater increase in the size of the fast twitch muscle fibers, but an ability to selectively recruit them. Because fibers are normally recruited on a smallest to largest basis, the ability to selectively recruit fast twitch fibers is referred to as synchronization. This ability allows an elite athlete to generate greater strength more efficiently, or at least more quickly. This ability is also trained most effectively with training loads in excess of 85 percent.



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