In 100-m dash, most of the energy consumed by skeletal muscles to replenish ATP is derived from
## **Core Concept**
The question tests understanding of energy sources for skeletal muscles during high-intensity, short-duration activities like the 100-m dash. The primary energy systems involved in muscle contraction are the phosphagen kinase system, glycolytic system, and oxidative phosphorylation.
## **Why the Correct Answer is Right**
During a 100-m dash, which lasts approximately 10 seconds, the body relies heavily on the **phosphagen kinase system** (also known as the phosphocreatine kinase system) for ATP replenishment. This system is crucial for high-intensity, short-duration activities. It rapidly replenishes ATP by transferring a phosphate group from phosphocreatine (PCr) to ADP, yielding ATP and creatine. This process is anaerobic, meaning it doesn't require oxygen, and is the primary source of energy for such brief, intense efforts.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because, while the **glycolytic system** does contribute to energy production during the 100-m dash, it is not the primary source. The glycolytic system breaks down glucose to pyruvate, generating a small amount of ATP and NADH in the process. This system is also anaerobic but takes slightly longer to produce energy compared to the phosphagen kinase system.
- **Option B:** This option is incorrect because **oxidative phosphorylation**, which occurs in the mitochondria and requires oxygen, is not a significant source of energy for activities as short as the 100-m dash. Oxidative phosphorylation produces the majority of ATP during prolonged, low-to-moderate intensity activities.
- **Option D:** Without specific details on what this option entails, we focus on the rationale provided for the correct answer and the incorrectness of A, B, and the implication that C is correct.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that for activities lasting less than 10 seconds, the **phosphagen kinase system** (or ATP-PC system) is the predominant energy source. For activities lasting 10-90 seconds, the **glycolytic system** becomes more significant. This differentiation is crucial for understanding human physiology and performance.
## **Correct Answer:** .