We must first understand the difference between indoor spinning and ordinary bicycles and mountain bikes. Most indoor spinning bikes have a "flywheel", which is a 30-to 40-pound wheel. When you pedal, it can provide resistance, which is the main reason why the pedal of the spinning bike continues to move after stopping pedaling. The function of this flywheel setting is to keep your legs moving to slow down the resistance of pedaling. Outdoor riding comes more from road friction and wind resistance, which requires more hip muscles and quadriceps.

Cycling will burn more calories.