Strength Training | Training Tips

How to Maximize Fitness with Energy Systems Training

ISSA, International Sports Sciences Association, Certified Personal Trainer, ISSAonline, How to Maximize Fitness with Energy Systems Training

Reading Time: 5 minutes 48 seconds

The body requires energy to sustain life. When engaged in a high intensity exercise, this need is even greater. Even sedentary activities need a constant supply of fuel, although at a slower rate. Understanding the body’s use of energy is critical. It is only then that you can create an effective energy system training program.

What is Energy Systems Training?

The main source of energy in the human body is adenosine triphosphate or ATP. ATP consists of adenine, ribose (sugar), and three phosphates. When the bond between the three phosphates breaks, energy is released. The ATP molecule must then be re-formed. If it isn’t, energy stores would stay depleted. 

Maximizing this cycle ensures that the body has enough fuel to live. It also provides the energy needed to exercise. It makes it possible to engage in aerobic work and resistance training. This is why energy system training is so important. Without it, clients will be too fatigued to work out.

Energy system training involves teaching the body how to create adequate supplies of energy. The right training elicits the amount of ATP needed. This energy provides the fuel for higher levels of physical activity. Different sports use different amounts of energy.

The term “energy system training” includes three different energy systems. The one used most during an exercise depends on its intensity and duration. Yet, they must all work together to supply the energy the body needs to complete a workout from start to finish.

The Phosphagen System

The main source of fuel for the phosphagen system is phosphocreatine. Phosphocreatine is one molecule of creatine and one molecule of phosphate. When phosphocreatine releases its phosphate molecule, it helps replenish the body’s ATP.

The body can synthesize creatine. The kidney, pancreas, and liver all contribute to this process. Muscle tissue stores excess creatine. This is also where the creatine binds to phosphate. The phosphocreatine releases its phosphate when a specific enzyme is released. This provides the energy the body needs. 

Some athletes increase their body’s creatine levels by taking a supplement. This increases creatine stores within the muscle cells. It allows for more bonds with phosphate, thus more energy. The result is less muscle fatigue. It also boosts muscle performance.

The one thing to know about this energy system is the energy it provides is short-term. That makes it beneficial to athletes engaged in short bursts of exercise. An example of this is a bodybuilder engaged in a strength training session.

If the activity is longer-term, a different energy system supplies the body ATP. Activities requiring more muscular endurance need more ATP as well. This type of system may be anaerobic or aerobic. 

The Anaerobic Glycolysis System

An anaerobic system is one that does not rely on oxygen for its processes. Thus, the anaerobic glycolysis system releases stored glucose in the absence of oxygen. This process is more effective at producing ATP than during phosphagen.

In the initial stages of anaerobic glycolysis, lactate increases. This is often referred to as lactic acid buildup. Athletes can feel the body’s switch to the glycolytic system. They will often notice a burning sensation within the muscle. 

Lactic acid has a bad reputation within the fitness field. Yet, lactate does provide a few benefits. One is that it can convert into glucose, supplying the body with more energy. The heart also benefits as it uses lactate to support a healthy heart rate.

The problem comes in when lactate accumulates faster than the body can get rid of it. This is the lactate threshold. Once this threshold is reached, it begins to impact muscle fiber. Physical performance declines and muscle soreness increases.

A more conditioned athlete generally has a higher lactate threshold. An endurance athlete, such as a marathon runner, would fall into this category. They can tolerate a higher level of lactate. This results in a higher anaerobic threshold.

In higher intensity training, the anaerobic energy system takes about seven seconds to kick in. It will continue to use muscle glycogen for about the next two minutes. If the exercise continues, this system is less effective. Instead, aerobic metabolism is needed to support the body’s higher energy demands.

Aerobic Metabolism

This energy system gives the body the fuel it needs to sustain longer exercise sessions. How is it different than the glycolytic system? The aerobic energy system relies on oxygen to produce ATP. 

The first stage of the aerobic system is the Krebs cycle. The Krebs cycle occurs in the mitochondria and begins the aerobic metabolism process. Oxygen is consumed. This triggers the oxidative system. ATP is produced and the body expels carbon dioxide and water. 

Aerobic metabolism relies on four different sources of fuel. They are glucose, fatty acids, lactate, and ketones. Each one converts into an enzyme (acetyl-CoA). This is the enzyme used during the Krebs cycle to begin the breakdown of ATP.

The more fit an athlete is, the faster the aerobic system begins to take over. An unfit person can take up to four minutes to use the aerobic energy system during an exercise session. An athlete engaged in aerobic training can access their aerobic system much faster. They can be at full capacity in about one-quarter of the time, or within one minute.

Remember that aerobic glycolysis occurs in the mitochondria. The more mitochondria you have, the greater your access to energy. And the greater your ability to exercise for longer periods. Aerobic training increases the mitochondria in muscle tissue. This enables the body to create more ATP. As aerobic fitness increases, so too does energy production.

ISSA, International Sports Sciences Association, Certified Personal Trainer, ISSAonline, How to Maximize Fitness with Energy Systems Training , Strength Training

Creating an Effective Energy System Training Program

Once you understand how each of these energy systems works, you can create a training program that utilizes each. The one the body uses most depends largely on exercise intensity and duration. Less intense training is more anaerobic than aerobic. Shorter duration activities rely on the phosphagen and glycolytic systems for energy. Endurance training depends more on the aerobic energy system.

Creating a training plan that relies on each energy system offers maximal results. This involves developing a plan that varies in intensity and duration. Mix high-intensity interval training with long-distance runs, for instance. Also include activities that increase heart rate and activities that build muscle. Combine cardio and strength training for a complete exercise routine. 

Teaching the body to better use each energy system gives it access to them all. This supplies maximal energy and power as dictated by the activity itself. It also provides a more well-rounded exercise program. A program that offers clients a higher level of fitness.

Individual Athlete Considerations

It is also important to consider the sport your client plays. Those engaged in endurance sports need a higher aerobic capacity. Those taking part in anaerobic activities rely more on energy systems that don’t use oxygen.

For example, research reveals that tennis players rely on anaerobic metabolism. Only five percent of their energy comes from aerobic sources. This is because for every second spent playing, they spend 2.3 to 3.27 seconds at rest. Thus, they benefit more from training their anaerobic energy systems.

Another study looked at hockey players. In this case, participants took an on-ice skating test. They assessed their recovery rates pre- and post-season. Researchers concluded that on-ice training sessions helped improve their aerobic system. Clients participating in similar sports would likely notice the same effect.

Look at your client’s sport of choice. Try to determine how much time they are active and how much time they are at rest. If they have shorter bouts of effort, work to build their anaerobic energy system. If their sport needs continuous effort, focus more on their aerobic energy system.

Using Nutrition to Supplement Energy System Training

Each of the energy systems relies on base substances to operate. How do you ensure that the body has access to these substances? By suggesting that clients eat a balanced diet.

For example, the aerobic system relies on glucose and fatty acids for fuel. A diet that contains both carbs and fats supply these bases. It provides the foundation for effective energy production. 

Supplements can help better meet these needs. In the case of phosphagen, taking creatine may help. This increases the levels stored within the muscle, supporting greater ATP production.

Want to learn more about energy systems and how to maximize your training? The ISSA offers Strength and Conditioning Coach certification. This course offers an entire section about how energy functions in the body. It provides a thorough understanding of the three systems involved. It also teaches you how to use each one best.


Featured Course

Strength and Conditioning

Sports are big business-profitable for athletes and individuals who prepare athletes for competition. Professional and amateur athletes at all levels -- from grade-school club teams to the National Football League -- need the assistance of expert personal trainers to excel at their sports.

View Product