Know Your Body's Energy Systems
Short foreword here. This article is information dense and a little scientific. All concepts are important to understand. You don’t need to know all the fancy names but the important things I want you to take away from this are the systems and how they function. When you understand that, you can manipulate your workouts to best fit your goals! Ok, now to the good stuff!
Your ability to exercise, move and even think depends on the body’s ability to breakdown the food we eat and convert it into energy. Adenosine Triphosphate (ATP) is the body’s ‘energy currency’ and is produced by three separate energy systems. These systems generate energy at different capacities and at different speeds, to cater to all of your body’s needs. Which system is most dominant will depend on the intensity and duration of activity. It is important to note that these systems do not work in isolation of each other but rather they can, at times, work together to produce energy for movement.
The Two Anaerobic Systems
These two systems are said to be anaerobic in that they do not use oxygen to synthesise ATP energy. These systems produce energy quicker but they also fatigue faster.
The ATP-PCr System. This system involves a chemical process using specific enzymes, which break down creatine phosphate (PCr) to produce phosphate and energy. These compounds then go on to rebuild ATP energy. This is the first system to activate during the first 5 seconds of physical activity. It is relied upon almost exclusively during this time. The ATP-PCr system can generally sustain activity for a period of 3-15 seconds.
The Glycolytic System. In the case that activity continues past 15 seconds in duration, the body must rely on the Glycolytic System for ATP energy. This system relies on the production of energy from muscle glycogen which is the storage form of glucose. When this process occurs without the presence of oxygen, it also produces lactic acid. At around the 30 second mark, this system is the most dominant. Although this system can fuel activity up to 120 seconds long, the production of lactic acid can cause your muscles to feel fatigue, which in turn can limit performance.
Aerobic System
The Aerobic System has a heavy reliance on oxygen and is a more complex process. This makes it slower at producing energy, but it can sustain activity for longer periods of time. The Oxidative System – Low Intensity This system involves a similar process to the Glycolytic System, however, it involves oxygen, which makes it significantly more complex. A series of chemical reactions inside the cells, plus the heavy reliance on the circulatory system to supply oxygen, makes this system a lot slower to kick in. This system is most dominant for activity lasting more than a few minutes.
Energy Systems and Different Training Styles
Endurance
This style of training involves low resistance for long periods of time, for example jogging. The Aerobic system is the most relevant to endurance athletes, as it is the exclusively dominant system at 110 to 150+ seconds into activity. As this system requires oxygen, this can be a limiting factor in one’s performance. You can increase this system’s efficiency by training at any intensity, more often and for longer periods of time.
Strength
Generally this style of training involves lower repetitions with higher resistance, for example barbell bench press. Exercise is performed for usually less than 30 second intervals with longer rest periods to recuperate energy stores. Due to the shorter duration of exercise, strength training relies mostly on the ATP-PCr system. Training within this 30 second window is beneficial, as it diminishes the role of the Glycolytic System – which has a by-product of lactic acid build up, which can interfere with muscle contraction and performance.
Hypertrophy & Energy Systems
For muscle growth, evidence appears to suggest that a mixture of the anaerobic systems seems to be the most effective. Performing intervals of activity between 30-60 seconds counters the potential issue of lactic acid and creates an optimal amount of muscle tension, which is the main stimulus for muscle growth. Muscle tension diminishes as you venture further in the oxidative system so activity beyond the 60 seconds mark is not as beneficial for muscle growth.
Final Thoughts
Most athletic activity involves the cooperation of the three energy systems working together to produce ATP energy. Understanding their role in different types of activity will assist you in figuring out what is the ideal form of exercise to suit your goals!
If you have any questions regarding the energy systems, be sure to comment below! SIGN UP for the FREE BURN PROGRAM. Intense 10-week training regimen that will give you the best results of your life! Have a great week everyone. Remember… BE THE BETTER YOU!
