Energy Systems Part 1


 Energy systems during Exercise Part 1

Why are we interested in how our body powers our everyday movements and in particular how they respond to increasing levels of exercise? After all it just all works automatically without any thought or intervention on our part.

I suggest that during our daily and night time activities (including sleeping) we just let our bodies get on with it. However when it comes to athletic training it is important to have some understanding of the way out bodies are powered so that we can plan and complete effective training strategies.


The above diagram gives a representation of when running at longer and longer durations that our amount maximum speed or power  falls off as shown by the shape of the black curve. It falls off quite rapidly at first before levelling off after a few minutes. We know that we can't keep running at our  maximum 100m speed for the full distance of a 10k race for example. 

Power/Duration curve from WK05 created by Palladino Power Project

The above is a similar curve showing the impact of the three main Energy systems on max Power or Speed over longer and longer durations. In this case the colours indicate the training zones that many of us use in performing training workouts. The higher intensity zones to the left with the lower intensity to the right.
It is important to realise that the three energy systems do not work in isolation but are producing energy all the time in varying amounts and have impact on each other. Each system has its own strengths and weaknesses. 

The more energy that is made available per second, the harder (more intensely) the muscle can operate. If, for any reason less energy is made available, the intensity of muscular activity will decrease, forcing the runner to slow down. Energy is produced in the muscle via a molecule called ATP (adenosinetriphosphate). The working muscle captures the energy carried by ATP to contract. ATP is present in the muscle in only very small quantities and needs to be continually restored to allow movement and exercise to continue.

This is where the three main energy systems come in to play. They use the carbohydrates, fats and protein in various proportions in our diet as fuel in the process of regeneration of ATP.

  • Alactic
  • Anaerobic Lactic
  • Aerobic

 

From "The Secret of Running" by Hans Van Dijk and Ron Van Megan

From "The Secret of Running" by Hans Van Dijk and Ron Van Megan

So you can see that depending on the target running event you are training for your body needs to be good at utilising energy in a specific way. The longer the event you need to be better at generating energy to the right of the curve and the shorter the event, to the left of the curve. Unfortunately you can't just train one particular energy system without impacting on one or more of the others. Nor can one workout deliver improvements to all simultaneously.  So it becomes more of a trade off between gains in one area at the expense of another. Add to this the fact that everyone is an individual with their own genetics and training history. For example it is said that your ability to use Oxygen to its maximum may be largely genetic as is the composition of muscle fibre types between so called Slow twitch and Fast twitch.


So going back the top of this post hopefully I have given some indication of the thoughts and issues that need to be considered in producing a training plan and execution of specific workouts.

Part 2 Energy Systems

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