Energy Systems Quiz 8/20/26

What are the 3 primary bioenergetic pathways?

Phosphagen (ATP-PCr) System, glycolytic (lactic acid) system, and the aerobic system.

What do the 3 systems supply?

ATP for muscle contraction

How do the systems differ?

Speed of ATP production, substance use, oxygen dependence, & intensity/duration of the activity they support.

Phosphagen (ATP-PCr) System:

Fastest pathway, Rapid generation, limited capacity (5-15 seconds of max effort), No oxygen needed and no lactate produced, dominant in short durations, all effort out exercises such as; 1 rep of a max lift or first few seconds of a sprint.

Glycolytic (Lactic Acid/Anaerobic Glycolysis):

Breaks down glucose or glycogen to pyruvate via glycolysis, medium speed, provides energy for high intensity efforts (15 secs to 2-3 mins), produces lactate that contributes to fatigue, Activities include: 400m sprints or repeated heavy weight lifting sets.

Aerobic (Oxidative) System:

Oxygen dependent (Carbs, fats, and proteins are fully oxidized in mitochondria), Slowest rate of ATP but has greatest capacity, dominates in prolonged lower intensity continuous activities (longer than 2-3 minutes), Activities include; distance running, cycling, or team sport play.

When does Glycolysis become primary?

As PCr declines

When does the contribution of each system change?

As duration and intensity of the efforts change.

Sprint Events (<15 seconds):

Cycling sprints; Phosphagen (87% energy) and declines to (50%) by 12 seconds. 100 meter sprints; Phosphagen (61-70%), Glycolytic (23%), aerobic (9%). 15 second sprints; Phosphagen (45%), Glycolysis (48%), and aerobic (7%).

When does the Glycolytic system peak in a sprint?

At about 6 seconds.

Middle Distance Sprints (60s-4mins):

Duration longer than 30-60 seconds causes glycolytic system to dominate (42% energy). 400m run; anaerobic (62-63% total energy), glycolytic (about 30%).