What type of energy system primarily provides energy for activities lasting up to 90 seconds?

The correct answer focuses on the creatine phosphate energy system, which is crucial for short bursts of high-intensity activity that last up to about 10 seconds. However, the primary energy system for activities lasting up to 90 seconds is actually the anaerobic energy system.

The anaerobic energy system includes both the phosphagen system (which utilizes creatine phosphate) and anaerobic glycolysis, which kicks in as exercise duration extends beyond the immediate energy provided by the creatine phosphate system. During activities between approximately 10 seconds and 90 seconds, the body primarily relies on anaerobic glycolysis to produce ATP, leading to lactate accumulation as a byproduct.

Thus, while the creatine phosphate system is significant for very intense, short-duration efforts, the sustained activity lasting up to 90 seconds will predominantly involve anaerobic glycolysis. The aerobic energy system becomes the main contributor only when exercise continues beyond this timeframe, specifically in longer-duration activities where oxygen is utilized more efficiently for energy production.

In summary, for activities lasting up to 90 seconds, the anaerobic energy system plays the key role, especially in high-intensity efforts, while the creatine phosphate system supports the initial, very short bursts of intense exercise.