Movement Highlight: Systems at Play During Your Workout


While we may not have appreciated our ninth grade biology class at the time, as we mature we can’t help but admit the human body is fascinating! It’s even more interesting because the more you know about how the body works, the better you can train it to work effectively. At Nexus we are committed to using what we know to provide our members with top-of-the-line workouts that are challenging and target specific muscle groups. 

The human body uses three different systems to produce energy: the phosphocreatine system, the anaerobic system, and the aerobic system. Each one of these systems is constantly working during exercise, but in varying degrees, as the system that is activated the most depends on the intensity and duration of the workout. 

The phosphocreatine system activates during high-intensity sessions when you’re going all out and giving maximum effort. The energy generated is quickly consumed and takes time to recover so it’s only good for a short period and requires a lot of rest. When we target this system, we look to train your fast-twitch muscle fibers to build stronger, more powerful muscles. Maxing out on a lift is a prime example of using this system, as well as 10-second TrueForm sprints! 

The anaerobic glycolytic system, also known as the lactic system, starts to work after the first 10-12 seconds of an intense workout and can last up to a few minutes depending on the workout. We utilize the anaerobic system through heavier lifts that train muscular endurance and strength. This is activated for 30 seconds to three minutes, as well as during a 10-minute interval workout on one of our machines. There are several important health benefits to training and using your anaerobic system, including oxygen consumption, muscle building, and cardiovascular endurance. In addition to providing you with tremendous health benefits, the anaerobic system also works after your workout through a process called EPOC (excess post-exercise oxygen consumption) to help restore oxygen levels that were diminished during your workout, allowing for the HIIT workout to be effective well after your last interval! 

The final system we work during a Nexus class is your aerobic system. You tap into this system after three minutes of low to moderate intensity workouts such as a 20-minute AMRAP or a 60 minute light jog/row. After the initial use of the anaerobic system wears off, our bodies begin to lean on our aerobic system to meet the demands of oxygen intake so we can maintain effort. The health benefits to aerobic exercise include faster recovery times, lower blood pressures, and improved cardiovascular health. Fun fact, you can improve your aerobic capacity through circuit training. Research shows that training your phosphagen and glycolytic systems through high-intensity interval training also increases your aerobic system! We designed our X⁴ program as a perfect culmination of high-intensity and necessary duration to capture the benefits of training each of these systems.

There are so many good reasons to exercise. The metabolic and structural adaptations to both anaerobic and aerobic activities can make us stronger, fitter, healthier, as well as give us a better quality of life for longer! With a team of coaches that understand how different workouts affect the body, we feel confident that you will receive the best training possible, tailored to your fitness needs! If you have any questions about these systems and how we program our workouts around these systems, ask us during your next class! 

Thanks to our head coach, Jake King for providing this blog and providing challenging workouts that make us better inside and out!