Get in shape fast with professional circuit training software: "Fit Kit".Whether you need to lose weight or to increase muscle size fast, Fit Kit can help. Fit Kit is professional circuit training software with a variety of circuits built in to the software and new circuits being made available regularly as well as an ever growing list of exercises each with detailed instructions. Currently there are 9 circuits built in to Fit Kit which vary in difficulty from light workouts to challenging circuits, as well as 23 different exercises with detailed instructions.