Muscle Movement and Energy Systems

Muscle Movement and Energy Systems

In this post, I am going to discuss understanding how our muscles work.  This can help us understand how to workout our muscles and optimize muscle recovery.  The predominant theory around muscle activation is the sliding filament theory.  To spare the in-depth details, muscles are believed to have little “arms” that slide across a muscle fiber to create a muscle to contract or shorten, i.e., a bicep or arm curl. 

To create a muscle contraction several things have to happen: 1) the muscle needs to receive a stimulus to move from the brain via the nerves, 2) the electrical stimulus from the nerve releases sends a signal for the muscle fiber to contract, 3) energy is released from the electrical signal to cause the muscle arms to move (this energy is called ATP, Adenosine Tri-Phosphate), 4) the muscle re-polarizes to repeat the muscle contraction.  However, there is a limit to this process.  This is why it is important to understand the process of muscle contraction because it affects our recovery period for various exercise goals.

A perfect example of the influence of energy systems on movement is a marathoner. We have all seen a marathon runner “hit the wall.” This is the point where the runner is literally out of energy and cannot move any further. They look almost drunk, disoriented, and weak.

Energy Systems

There are three main energy systems 1) Phospho-creatine, 2) Anaerobic, and 3) Aerobic Glycolysis.  These energy systems help us move based on the action that we are taking.  Remember that we are going to look at them in a vacuum, but they are always being used concurrently in some way shape or form.

Creatine system - This is the fastest most explosive system.  It only lasts for about 30 seconds, so think of a 1-RM Bench Press, hitting a baseball or kicking a soccer ball.  This is designed for short bursts of energy.  The phospho-creatine system uses creatine to hold onto a phosphorus ion that can be used to create ATP fast. It is used the fastest, but takes the most time to recover, up to 5 mins for full recovery.

Anaerobic system - This is the process of using sugar without oxygen to make ATP (energy).  This is used for short distances think less than 2 mins, i.e. a sprint.

Aerobic Glycolysis (fancy term for using oxygen to breakdown fat) - for those who would like to know more, this is described in the Kreb’s Cycle to use oxygen to get ATP (energy) from fat.  This is the most efficient energy system in the body, but it takes a while to be used, starting when exercise is over 2 mins.  Also, to get to optimal fat burn from calories, it takes over 90 mins.  This energy system is used for long periods of continuous activity, think of marathon running. 30-90 seconds for full recovery.

All of this information is where rest intervals come from for between sets.  To optimize workouts, it is important to understand how to optimize muscle recovery for what you are trying to achieve. Going back to the example of the marathoner, they all do a series of carbo-loading (eating increased breads and pastas) leading up to a marathon to make sure their energy stores are at peak capacity. This is an effort to prevent “hitting the wall.” Know your workout goals to optimize your training.