Fitness Level is a reward system for consitency. When you start with StepN GO you start with 100% earnings (called soft feet).
After a few days the earnings will decrease to 50% (called sore feet) but after a few more days it will rise up to 150% (called strong feet).
The progression by day: 100/100/90/80/70/60/50/50/70/90/110/130/145/150.
For the Fitness Level to rise, you need to consume 2 energy EVERY day.
This does not apply to Guests or Gift Bag users.