The Fitness Junction

This week:

• Knowledge Corner: How does energy production affect endurance?

• Monthly Challenge Update: 1000x KB swings in April

• Meme Center: A friendly reminder

Knowledge Corner: Energy Systems & Endurance

Pop quiz! In the human body, what molecule is the primary source of energy? Gold star for you if you said adenosine triphosphate (ATP). If ATP rings a bell, its probably because you memorized it back in high school to pass a biology test. The reason I bring it up now is to help explain how your body produces energy. There are three pathways for generating ATP and understanding how they work will allow you to train optimally for endurance. Every sport/activity relies on a different blend of the three ATP-producing processes. By identifying which pathway is most relevant to your fitness goals, you can customize your training plan to maximize results.

If your body was a car, ATP would be the gasoline. It is the molecule that enables us to move by facilitating muscle contraction. The three ways the body produces ATP are:

• ATP-Phosphocreatine (ATP-PC) system

• Glycolytic system

• Oxidative (aerobic) system

The first two systems are anaerobic, meaning they do not require oxygen to make ATP. The oxidative system does require oxygen, which makes it aerobic. All of the body's energy needs are met through the combined efforts of these three systems as shown by this graph:

Here is how to interpret this graph: For maximum immediate energy, your body will utilize the ATP-PC system. The ATP-PC system relies on energy sources already stored in the muscles which are exhausted rapidly. Before ATP-PC energy is fully depleted, the glycolytic system takes over and supplies ATP to sustain maximum effort for ~30-60sec. By then, the oxidative system will be ramping up ATP production to take over. The energy from the oxidative system can last for a very long time to support steady-state effort utilizing all the energy stores in your body (like body fat).

If an activity demands short periods of maximal exertion, then you will rely heavily on the two anaerobic systems. For example, a highly explosive sport like gymnastics requires the ATP-PC system to provide a large majority of ATP, whereas a steady-state sport like rowing relies mostly on the aerobic oxidative system. Here are some more examples with the percentage of each system that they rely upon:

So why am I hitting you with at this jargon and nerdy exercise science stuff? Once you understand the three energy pathways, you can optimize your training program to increase endurance in the systems that are most important to you. Also, knowing this stuff might help you impress a date or win Jeopardy one day. I will address each energy system and how to effectively train specifically for them in future newsletters.

Trivia

You sometimes see elite athletes wearing intricate breathing masks hooked up to machines when working out on a treadmill or bike (they look like Bane from Dark Knight Rises). What are these experiments measuring?

• A. Does this person have stinky breath?

• B. Is this person a mouth breather?

• C. What percentage of exhaled air is carbon dioxide (CO2) based on different heart rates?

• D. What is the maximum amount of oxygen this person can consume during exercise?

April Challenge: 1000x Kettlebell Swings

Off to a good start. These are proving to be a nice addition to my regular workout routine. If you're following along with this challenge, I recommend mixing up the weights and reps if possible. Go heavy for 10 sets of 10 swings or go lighter for 2 sets of 50.

Meme Center

Trivia answer: D. What is the maximum amount of oxygen this person can consume during exercise? This measurement, also called VO2 max, is a great way to assess your aerobic endurance. Now that you understand the oxidative system, it's easy to see why increasing your VO2 max would increase your capacity to produce ATP, and ultimately increase endurance.

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