Exercise Physiology – What happens to my body when I first perform strength training?
Hey everyone, hope I don’t lose you all with some of the content of this article. There may be some parts that go over your head a little but I think it is of much importance to understand what is happening within our bodies when we are training, this then helps us to understand why we are or are not changing on the outside of our bodies the way we desire.
Exercise Physiology – The first 2 months of Strength Training!!
Whenever an individual begins resistance training for the first time, many physiological adaptations occur within the body. During the early phases of training, a person’s strength will increase much faster than any growth in muscle size. This is due to the neural or nervous system adaptations within the body. As your nervous system builds stronger links to your muscles cells, you will see increases in muscle memory and a dramatic increase in muscle strength in the beginning. There have been many studies performed with regards to these neural changes, with one study noting a 30% increase in strength in its untrained clients in the first 2 months of training, with no accompanying increase in muscle fiber size (hypertrophy). Other studies have also reported a tiny contribution of muscle size to strength and strength increases that are disproportionate to muscle size increases.
When beginning an exercise program it is important to understand what, how and why you are improving at various stages of the program. During the first 6-8 weeks, the gains made are due to neuromuscular adaptations within the body. Following this initial period, changes in muscle cross-sectional area will be more responsible or strength gains. It is also worth noting that the poor lifting form that novice weightlifters display is due to their lack of neural function. Just like learning any new skill, it takes the body time to become coordinated.
So what functions are the physiological changes responsible for these strength gains?
There are several hypothesized reasons for these strength gains. The following are the most widely considered responsible:-
· Increased motor unit activation – a motor unit consists of the motor nerve cell (neuron) that originates in the spinal cord, and all the muscle fibers it controls. When a motor unit is activated, all of the muscle fibers under the supply of the neuron contract equally, it is an all or nothing principle. Because of this, to control muscle force production, the motor units will fire at different frequencies and different amounts of motor units will be recruited to the muscle. Strength training has the ability to improve the activation and the firing frequency of these motor units which allows for greater force production.
Neural cross-education – It has been proven that in an untrained person we can increase the strength of one arm, by training the opposite arm unilaterally. A study in 1979 showed an increase of 36% of maximum force production for the bicep muscle on the arm that was trained, while a 25% increase occurred on the opposing side that was not trained at all. This is attributed to a phenomenon called cross education, where the nerves on either side of the spinal cord communicate with each other for more efficient movement. This is also why we are able to produce more force when we are performing single limb activities rather than bilateral movements.
· Synchronization – this refers to the timing of action potentials from active motor units. In muscle cells, an action potential is the first step in the chain of events leading to a contraction of the muscle. The motor units in strength athletes are much higher than those of untrained individuals and as we begin our strength training program, the synchronization within our body improves, aiding in more force production from our muscles.
Some other random facts about our neural system and how it controls all that we do;
· In a concerning finding for all gym goers and one that I hope not too many people take hold of, it has recently been proven that shouting during exertion can actually increase strength. The same can be said if a pistol is fired near the subject shortly before a test. Now I don’t recommend either of these in your local gym as you may become very unpopular, very quickly with either of them, but it does show how the excitement of the central nervous system can improve your strength gains.
· It has also been noted that subjects have shown increases in strength following imagery and visualization. Subects who imagined themselves lifting weights heavier than they originally could, were shown to increase strength compared with the subjects who performed no imagery. Again, this shows the power of the neural system and how having it primed for exercise is the way forward for you.
To maximize any improvements in strength and fitness in our training, our programs need to be constantly modified, varied and progressed. This will ensure that neural gains do not plateau too soon. In the human body, our body will adapt to the specific demands that we place upon it, there is very little cross over in strength from one movement to the next. We must train our bodies from all angles, with various contraction types, various loads and various joint positioning. This gives us the greatest benefit and cross over to everyday tasks and sports performance.
The changes I have spoken of above are greatest within the first 2 months of training, following this initial burst, changes in muscle size and shape become the primary enabler to strength gains. But that is for another time 🙂