Questions: What is the goal of proprioceptive neuromuscular facilitation (PNF) stretching? A) To improve muscular endurance B) To enhance both passive and active range of motion C) To increase muscle strength D) To increase body temperature What is the primary difference between aerobic and anaerobic energy systems? A) Anaerobic occurs in the mitochondria; aerobic occurs in the cytoplasm B) Aerobic requires oxygen; anaerobic does not C) Aerobic uses carbon dioxide; anaerobic does not D) Anaerobic produces more ATP than aerobic

The answer to the first question is (B): To enhance both passive and active range of motion.

Explanation:

• (A) To improve muscular endurance: This is incorrect. PNF stretching is not primarily aimed at improving muscular endurance; it focuses on flexibility and range of motion.
• (B) To enhance both passive and active range of motion: This is correct. PNF stretching is designed to improve flexibility by increasing both passive and active range of motion through techniques that involve stretching and contracting the muscles.
• (C) To increase muscle strength: This is incorrect. While PNF stretching can involve muscle contractions, its primary goal is not to increase muscle strength but to improve flexibility.
• (D) To increase body temperature: This is incorrect. While stretching can slightly increase body temperature, this is not the primary goal of PNF stretching.

The answer to the second question is (B): Aerobic requires oxygen; anaerobic does not.

Explanation:

• (A) Anaerobic occurs in the mitochondria; aerobic occurs in the cytoplasm: This is incorrect. Aerobic processes occur in the mitochondria, while anaerobic processes occur in the cytoplasm.
• (B) Aerobic requires oxygen; anaerobic does not: This is correct. The primary difference is that aerobic energy systems require oxygen to produce energy, whereas anaerobic systems do not.
• (C) Aerobic uses carbon dioxide; anaerobic does not: This is incorrect. Neither system uses carbon dioxide; aerobic systems produce it as a byproduct.
• (D) Anaerobic produces more ATP than aerobic: This is incorrect. Aerobic systems produce more ATP per glucose molecule than anaerobic systems.

In summary, PNF stretching aims to enhance both passive and active range of motion, and the primary difference between aerobic and anaerobic energy systems is the requirement of oxygen in aerobic processes.