Our bodies use three energy systems to facilitate any activity:
1- The phosocreatine pathway uses ATP to produce powerful immediate energy
2- The glycololitic pathway uses glycogen stores to produce fast energy
3- The oxidative uses oxygen to provide sustained energy.
What researchers have found over the years is that regardless of the task involve all energy systems are in use. Albeit some more than others depending on the task, all three energy are in play. Let’s repeat this point, your body doesn’t use one energy system exclusively, rather it’s more of one and less of the other depending on the needs required.
Consider this illustration and notice how there is some overlap of all the energy system.
With this is mind it’s important to consider the best method of training for a sport.
Should a weightlifter only lift? Let’s look at this diagram:
Notice that from the time the activity starts all three energy systems are at play. Within the first ten seconds the phosphagen system has already peaked. At this point the glycolytic system and the aerobic system now start contributing a bigger portion of the energy required.
Let’s look at a real-life example. In a clean and jerk, from the start of the first pull on the clean and prior to the jerk being initiated, 10 seconds has often passed. Not to mention that the athlete must still recover their feet and maintain the load until a down signal, often the total time from start to finish will exceed 20 seconds. Every second that passes the body recruits more energy from other sources outside of the powerful phosphagen pathway. Thus, in this it becomes critical to have a well-developed glycolytic and oxidative systems to support the efforts of the phosphagen pathway.
In the video above Kelsey Rhode takes 19 seconds from her first pull until the moment she receives the down signal.
Alternatively, your ultramarathon runner will benefit on working in the phosphagen pathway. Consider this, your ultra-marathoner is 1 hour into a 6-hour race, suddenly comes across a fallen tree in his path, does he walk slowly around it or does he accelerate and clear the obstacle. If you would prefer that your athlete can have the ability to apply a sudden burst of quick energy, then they will need to have this well develop energy system.
Personally, I have trained athletes at both end of the spectrum and continue to do so. Base on the needs of the athlete I will set their individual program to emphasize the development of that energy system but not without some complimentary work in the other energy pathways. Over the last few years I’ve seen huge benefits to introducing more anaerobic and aerobic work to my lifters and explosive work to my long endurance athletes.
I personally hate hearing lifters say that don’t need to work on their aerobic system, this is an old-school mentality that has been debunked. The benefits of a well-developed aerobic system will contribute to better recovery between lifts and sessions, not to mention helping keep the all-important bodyweight in check.