In the glycolytic (lactic acid) energy system, typical work duration falls in which range?

• A. 30-120 seconds
• B. 30-60 seconds
• C. 60-120 seconds
• D. 10-20 seconds

Answer: (A)

The glycolytic (lactic acid) energy system is the workhorse for high‑intensity efforts that aren’t possible with the immediate phosphagen system but don’t yet rely on steady oxidative metabolism. It generates ATP quickly through anaerobic glycolysis, but fatigue sets in as lactate and hydrogen ions accumulate, limiting how long it can sustain maximal output. Because of this, the typical usable window for this system is about 30 seconds up to roughly 2 minutes. Shorter efforts (only a few seconds) depend mostly on phosphocreatine, while longer efforts beyond about 2 minutes shift toward aerobic metabolism. So the range that best fits is roughly 30 seconds to about 2 minutes.