Muscle metabolism changes in different types of physical activities. Let’s break it down simply:

1. Aerobic Activities (like running or cycling):

   • These activities need oxygen to create energy called ATP.
   • They mainly use fat and carbohydrates for fuel.
   • Your body builds more mitochondria, which helps you endure longer during exercise.

2. Anaerobic Activities (like weightlifting or sprinting):

   • These activities create ATP without needing oxygen, mostly using a process called glycolysis.
   • They use stored glycogen, which gives you quick energy for short, intense efforts.
   • This type of exercise helps you build muscle and strength.

3. Fatigue:

   • This happens when your energy sources run low.
   • It can also occur from lactic acid building up during anaerobic activities or from using up ATP in longer workouts.

In short, these changes in muscles help them meet the energy needs of different activities!