THE SCIENCE BEHIND HIIT - Research proves that High-Intensity Interval Training (HIIT) is the most effective method to increase endurance and build strength. With CTF you have over 200 classes a week, can burn up to 1200 calories in a class and keep burning calories for up to 36 hours. Classes are a 50-minute workout incorporating strength and endurance exercises to challenge you differently every day! No class is ever the same. Our trainers design each class to include interval cardiovascular routines, mobility and strength training. Open to all fitness levels, this class puts first-timers and fitness diehards' side by side to make progress at their own level, together in one community.