What is the main energy conversion that occurs when a person is running outside?

The main energy conversion that occurs when a person is running outside is the conversion of chemical energy stored in the body into mechanical energy for locomotion.

Chemical energy changes into mechanical energy because energy from digestion of food provides energy for the runner’s motion.

Correct. When a person runs outside, the chemical energy stored in the body is derived from the digestion of food. This energy is then converted into mechanical energy, allowing the runner to move and perform physical work.