High Intensity training can really deliver results when you go flat out, maintain high-quality form during execution and do not flag as the exercise spile up. Extreme Burn is hard enough to push you at every level: strength, speed, endurance, VO2 Max and recovery time. There is no time for down time here. Make the switch from one exercise to the next, fast and be prepared to push through the leaden feeling of fatigue. EC is a must. Really, it is.