Energy System Development – How It Can Help You

Today’s post dives into the topic of energy systems and how they relate to cardiovascular training.

A brief look at the 3 energy systems we’ll be talking about today.

1. Phosphagen – utilizes creatine phosphate during hydrolysis of stored ATP; most active during
very intense bouts of exercise with durations less than 30 seconds.

Examples: Bench press, 100 meter sprint, medicine ball slams, Olympic lifting

2. Glycolytic – utilizes carbohydrates found in the muscle or bloodstream; most active during intense bouts of exercise between 30 seconds and 2 minutes 

Examples: Interval training, tempo runs, resistance training with > 10 repetitions, some forms of circuit training

3. Oxidative – utilizes primarily carbohydrates and fats for fuel; most active during low to
moderate bouts of exercises in excess of 3 minutes.

Examples: Long bike rides, swimming laps continuously, morning jogging

Mike Stuart

Let’s take a look at 2 athletes. Jim and Jackie. 

Jim loves to lift weights and do short interval exercises. Sprinting, bike intervals, etc.

Jackie enjoys long distance running, swimming and biking and participates in triathlons regularly.

Both Jim and Jackie are fairly “fit” people, but in terms of energy systems, their fitness levels vary greatly.

Jackie is an Oxidative athlete. She runs, swims and bikes at low to moderate levels for long periods of time. Training energy systems is the same as training muscle tissues (“Use it or lose it”). For this reason, Jackie struggles with high intensity exercise that challenges her Phosphagen and Glycolytic systems. 

Jim is a Phosphagen athlete. He is comfortable lifting heavy weights for short periods of time.
Strenuous exercises doesn’t crush him in the same way that it does for Jackie. However, put Jim on a
bike for 15 minutes and he’s going to be sucking wind, sweating bullets and foggy for 3 days.

Here’s the question, what would be the benefits of improving Jim’s oxidative energy system? What about Jackie’s phosphagen and glycolytic systems?

In Jackie’s case, training the phosphagen and glycolytic systems could help to improve her lactate
, which is where the body starts to rely on aerobic systems for exercise. A higher lactate
threshold would lead to the same exercise feeling easier with improved performance. In her case, this
would mean biking at the same intensity with a decreased sense of effort. By training her two weakest
energy systems, her strongest energy system, the oxidative, would improve. Counterintuitive right?

In Jim’s case, training the oxidative system would lead to improved cardiac output, reduced resting heart rate, glycogen sparing (when the body utilizes fat in place of stored carbohydrate within the muscle) and increased capillary density. These adaptations would help Jim to train longer, recover faster and maybe even lose a little belly fat.

In both athletes, training the seldom-used energy systems would improve their training within their
energy system of choice. If Jim or Jackie has hit a plateau in their training, taking a hard look at energy
system development may be the step they need to take to improve their fitness levels.

Thanks for reading.



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