UNDERSTANDING ENERGY SYSTEMS

In this blog post we will cover the three main energy systems the body utilizes during various activities. What they are, when they are used, and how to train them to improve our over all fitness.

INTRO

Embarking on a fitness journey can be an overwhelming experience, especially for beginners. To optimize your workouts and achieve your fitness goals, it's essential to understand how your body produces and utilizes energy. In this blog post, we will cover human energy systems, how they work, and how you can train them effectively.

THE THREE ENERGY SYSTEMS

Our bodies rely on three primary energy systems to meet the demands of physical activity: the ATP-PC system, the glycolytic system, and the aerobic system. Each system provides energy in varying capacities and is utilized depending on the intensity and duration of exercise.

1. ATP-PC (Phosphagen) System

The ATP-PC system, or Adenosine Triphosphate-Phosphocreatine system, is one of the energy systems used by the body to produce energy for short bursts of high-intensity activities, such as sprinting or lifting heavy weights. This system primarily relies on the immediate availability of stored ATP-PC in muscle cells. ATP is the body's primary energy currency, and phosphocreatine helps regenerate ATP during intense, short-duration efforts. The ATP-PC system provides rapid but limited energy, typically sustaining maximum effort for about 10-15 seconds before other energy systems take over.

2. Glycolytic (Anaerobic) System

The glycolytic system, also known as the glycolytic pathway or anaerobic glycolysis, is one of the energy systems used by the body to produce energy, primarily during moderate to high-intensity physical activities that last longer than a few seconds but still require a burst of power. This system relies on glucose, which is converted into ATP (Adenosine Triphosphate) without the need for oxygen.

During glycolysis, glucose is broken down into pyruvate, producing a small amount of ATP in the process. However, glycolysis is an anaerobic process, meaning it does not require oxygen. The drawback is that it can produce lactic acid as a byproduct, which can lead to muscle fatigue and discomfort if the activity is sustained for a longer duration.

The glycolytic system is essential for activities like sprinting, weight lifting, and other moderate intensity, short-to-moderate duration efforts around 1-2 minutes when the body's demand for energy exceeds what the aerobic system can provide.

3. Oxidative (Aerobic) System

The oxidative system, also known as aerobic metabolism, is one of the body's primary energy systems for producing ATP (Adenosine Triphosphate). It relies on the presence of oxygen and is primarily used during prolonged, low-to-moderate intensity activities. Unlike the ATP-PC and glycolytic systems, the oxidative system is highly efficient at generating energy and can sustain activities for extended periods, such as endurance running or cycling.

In the oxidative system, glucose and fatty acids are broken down in a series of chemical reactions in the presence of oxygen to produce ATP. This process provides a steady and prolonged supply of energy, making it well-suited for activities that require endurance and can last for hours.

One of the key advantages of the oxidative system is that it does not produce lactic acid, which can cause muscle fatigue and discomfort. This system is crucial for activities that involve prolonged aerobic efforts and is the primary energy source during activities like long-distance running, swimming, or cycling.

TRAINING EACH ENERGY SYSTEM

Understanding how the energy systems work is crucial for designing an effective training program. Many make the mistake of creating a program that only targets one of these systems. What's worse, is sometimes it's entirely the wrong system to train in order to reach their goal! So here are some strategies and insight to appropriately train each energy system:

1. ATP-PC (Phosphagen) System Training

To improve the ATP-PC system's efficiency, focus on high-intensity, short-duration activities. Incorporate exercises like sprints, explosive weightlifting, and plyometrics into your routine. Aim for short bursts of maximum effort, followed by sufficient rest. 3-5 minutes between sets is recommended to allow for ATP and PC replenishment.

2. Glycolytic (Anaerobic) System Training

To develop the glycolytic (anaerobic) system, training with exercises that challenge your muscles' ability to sustain moderate to high intensity efforts. An example could be a moderate to heavy set of 8-12 reps of an exercise would target this system. 1-2 minutes of rest between sets is recommended for straight sets. Complex pairs, circuit training, and interval training are also excellent choices. These activities involve shorter bursts of intense exercise followed by brief recovery periods. Gradually increase the intensity and duration of each interval over time.

3. Oxidative (Aerobic) System Training

To enhance your aerobic capacity, engage in activities that elevate your heart rate for an extended period. Steady-state cardio exercises such as jogging, swimming, cycling, or rowing are ideal. Start with a comfortable intensity and duration and gradually increase the duration or intensity over time. Training and improving this systems is considered a hallmark of health, wellness, and longevity. Improving your aerobic system will result in a stronger, more conditioned heart, improved lung capacity, healthy blood pressure, and resting heart rate. The better conditioned the aerobic system becomes, the other systems will also benefit with shorter rest periods and improved removal of waste byproduct. Moral of the story is that aerobic training has a place for everyone, regardless of your goals.

CONCLUSION

Our hope is that this can bring understanding to those in the pursuit of fitness. The better we understand something the better we can manipulate to our advantage. There are countless options, methods, and approaches to integrating the balance of these systems. Our Online Coaching service and Capability Strength & Conditioning program includes training protocols to train all three of these energy systems for improved fitness and athleticism. Before we go, let's recap these points for reference:

ATP-PC (Phosphagen) System: Power/Explosive/Max Strength

• High Intensity/ Max Effort

• Shorts Bursts of Activity (5-10 seconds)

• Sprints, Plyometrics, Olympic Weightlifting, etc.

• 1-6 rep range

• 3-5 Minute Rest Between Sets

Glycolytic (Anaerobic) System: Strength/Hypertrophy

• High to Moderate Intensity

• Moderate Bouts of Activity (1-2 minutes)

• 400m Dash, Weight Lifting, Circuit/Interval Training

• 8-12 rep range

• 1-2 Minute Rest Between Sets

Oxidative (Aerobic) System: Muscular/ Cardiovascular Endurance

• Moderate to Low Intensity

• Longer Bouts of Activity (2 minutes and up)

• Weight Training with Light Weight at 15-30 rep range

• Walking, Jogging, Rowing, Biking, etc.

• Steady State: 10, 15, 30, 45, 60 minutes

• Limited to No Rest

We encourage you to cross examine these protocols with your current program and see if there are any areas to improve your routine. It is perfectly acceptable for your goals to be focused oriented around a singular attribute (strength, size, speed, endurance etc) that may only involve a certain energy system. While one can be focused and emphasized, it is still encouraged to address other energy systems in some capacity to stay healthy and well rounded.