Chapter 3 – Energy Systems/System Strength

There are three energy systems in the human body:

ATP-PC System

The body needs a continuous supply of ATP for energy — whether the energy is needed for lifting weights, walking, thinking or even texting. It’s also the unit of energy that fuels metabolism, or the biochemical reactions that support and maintain life. For short and intense movement lasting less than 10 seconds, the body mainly uses the ATP-PC, or creatine phosphate system. This system is anaerobic, which means it does not use oxygen. The ATP-PC system utilizes the relatively small amount of ATP already stored in the muscle for this immediate energy source. When the body’s supply of ATP is depleted, which occurs in a matter of seconds, additional ATP is formed from the breakdown of phosphocreatine (PC) — an energy compound found in muscle (1)

When is the ATP-PC system being used? (Think Fast Twitch)

The first process involves the high energy fuel phosphate creatine (PC also known as creatine phosphate). Creatine phosphate donates its phosphate to ADP to resynthesis ATP. The breakdown of PC does not require the presence of oxygen, therefore the ATP-PC system is known as an anaerobic system.

This energy system is for immediate activity for activities of short duration (lasting 0-10 seconds), high intensity & explosive activities, such as sprinting weight lifting, or gymnastics. , therefore fast twitch muscle fibres are recruited. (8)

The advantage of this system is that it is immediate/fast rate. The disadvantage is that the system is limited by the amount of PC stored in the muscles. Once PC begins to deplete at the muscle, ATP must be resynthesised from another substance. This energy system has a high rate but low capacity! (8)

This system uses ATP (universal form of energy existing in the cells of our bodies) that are found in the liver and muscles for quickly generated, accessible energy at the expense of running out of ATP depleting very quickly, making this system ideal for explosive, fast movements.

To develop this energy system, sessions of 4 to 8 seconds of high-intensity work at near peak velocity are required (3)

Let’s take a look at Bolt’s training methods: (8)

• 10 x 2 point start (10-20 meters) with 2 minute rest
• 6 x 3 point start (10-20 meters) with 3 minute rest
• 4 x 2 point block starts (10-30 meters) with 5 minute rest
• Sample Training Methods for the acceleration phase include:

• 10 x 20 meters with weight vest (up to 10% body weight) with 4 minute recovery
• 5 x 15 meters  2 point start with sled (20 kilos/men and 15 kilos/women) with 5 minute recovery

Sample Training Methods for the top end speed phase:

• 5x 30-meter acceleration
• 5x sprint 10-15 meters
• 5x 75% speed for 15-20 meters
• 5x sprint 10-15 meters
• 4-5 minute recovery

Sample Training Methods for the deceleration phase:

• 2-3 reps (2×100 meters) @ 95+% of 200 meter pace with 2-3 minute rest between reps with 5- 8 minutes rest between sets
  

From Bolt’s training methods, Th ATP-PC Energy System can be linked back to activities which recruit fast twitch muscle fiber types. Bolt has a very strong ATP-PC system meaning he can produce very large amount of energy using phosphocreatine in a very short time.

So if your goal is speed, then having a strong ATP-PC system and high composition of fast twitch muscle fibers would be ideal. But remember, with training, one can improve upon the ATP-PC system so even if you possess fast twitch muscle fibers but lack a strong anaerobic base, it can be trained in order to meet any goals you wish to achieve.

Lactic Acid System (Anaerobic system)

The lactic acid system, also called the anaerobic glycolysis system, produces energy from muscle glycogen — the storage form of glucose. Glycolysis, or the breakdown of glycogen into glucose, can occur in the presence or absence of oxygen. When inadequate oxygen is available, the series of reactions that transforms glucose into ATP causes lactic acid to be produced — in efforts to make more ATP. The lactic acid system fuels relatively short periods — a few minutes — of high-intensity muscle activity, but the accumulation of lactic acid can cause fatigue and a burning sensation in the muscles. (1)

The breakdown of glucose or glycogen in anaerobic conditions results in the production of lactate and hydrogen ions in the blood, creating the burning sensation we feel during anaerobic activity. (3).

Everyone has a different lactic acid threshold, meaning that people will start to produce lactic acid at different points of anaerobic activity. The advantage of having a high LT is that you can work at a higher intensity for a longer time before lactate levels become intolerable. (4)

The lactic acid system is a trainable system; with training, the lactic acid threshold can be moved up so that ATP production is steady and does not require lactic acid build up.

Research has indicated that training programs that are a combination of high volume, maximal steady-state, and interval workouts have the most pronounced effect on lactate threshold improvement. Incorporating these types of workouts into training can help raise your lactic acid threshold. The lactic acid system is a trainable system; with training, the lactic acid threshold can be moved up so that ATP production is steady and can rely on its energy for much longer before having to produce lactic acid. (5)

Many old school strength and sport coaches take the approach of more volume is better for teaching your body to ‘deal with it!’ and revel in the burn that the lactic acid brings. Athletes need to be prepared to perform at maximal velocity in this acidic environment. (7)

Anaerobic metabolism can be maximized by designing a program that combines maximum strength and power endurance training with 150- to 400-meter sprinting. (6)

To raise the threshold at which lactic acid starts to produce, redlining is an ideal training method that does so. Many cross-fit athletes do this to build endurance. Redlining is a term used to signify training over the lactic acid threshold for brief intervals of time and then resting for a duration before going over the threshold again for another cycle.

To extend the duration at which you are able to perform while over the lactic acid threshold, threshold extension training is key. To do this, you must barely go over the threshold and try to maintain the intensity for as long as possible while staying above the threshold.

Aerobic System

The most complex energy system is the aerobic or oxygen energy system, which provides most of the body’s ATP. This system produces ATP as energy is released from the breakdown of nutrients such as glucose and fatty acids. In the presence of oxygen, ATP can be formed through glycolysis. This system also involves the Krebs or tricarboxylic acid cycle — a series of chemical reactions that generate energy in the mitochondria — the power plant inside the body cells. The complexity of this system, along with the fact that it relies heavily on the circulatory system to supply oxygen, makes it slower to act compared to the ATP-PC or lactic acid systems. The aerobic system supplies energy for body movement lasting more than just a few minutes, such as long periods of work or endurance activities. This system is also the pathway that provides ATP to fuel most of the body’s energy needs not related to physical activity, such as building and repairing body tissues, digesting food, controlling body temperature and growing hair (1)

Putting It All Together

Three energy systems work in the body to provide energy. While these systems are well known for their role in fueling athletic performance, ATP is essential for every energy need in the body — including all the automatic body processes of growth, development and maintaining vital body functions. These energy systems do not work independently and do not function in isolation. Rather, all systems operate at all times, but some may predominate based on the body’s activities, including the type, intensity and duration of physical activity as well as a person’s fitness level (1)

1. https://www.livestrong.com/article/131444-3-energy-systems-body/
2. https://www.slideshare.net/JimmyNixon/energy-systems-60597667
3. https://www.brianmac.co.uk/energy.htm
4. https://www.active.com/triathlon/articles/lactate-threshold-and-v02-max-explained?page=2
5. https://www.unm.edu/~lkravitz/Article%20folder/lactatethreshold.html
6. https://canada.humankinetics.com/blogs/excerpt/understanding-energy-systems-training
7. https://powerathletehq.com/2014/03/11/alactic-threshold-training/
8. https://runboltrun.weebly.com/training-like-bolt.html