Compare how your body works during exercise to a motor.

It's quite simple actually

Explanation:

You see, the way the human body compares to a motor is the following. When you turn a vehicle on, it gives a signal go the computer of the car to give access to certain parts in the car in order to aid its successful ignition. Our body works quite similar to that. Let's use the example of signals of the vehicle's computer. Our brain uses signals to give out information to allow access to move our limbs, it's called Neurons. When neurons reach the brain matrix, it triggers another signal for the brain stem down to the nervous system, which then leads to our nervous system allowing use to move our limbs. Now, when a motor is working to keep the vehicle going, it works mechanically and processed. Our bodies are the same, we need our brain to process the signals in order for our body to function, or in this case, exercise.

Hope this explanation works out :)