Full Frontal is an hourlong indoor trainer session that puts riders through four different performance tests to get a clear picture of their strengths and weaknesses, which is then applied to future workouts. The net result of the Full Frontal test is a power profile Sufferfest refers to as 4DP — a rider’s four-dimensional power. Most anyone who has gotten deep into cycling physiology and focused workouts has done a Functional Threshold Power (FTP) test, a 20-minute effort that illustrates an athlete’s sustained aerobic endurance extrapolated to a one-hour effort. FTP is useful, but it really only reveals an athlete’s aerobic endurance; it doesn’t reveal anything about a rider’s ability to sprint, recover from intense efforts (such as an attack), or get over a short, punchy climb. All of these metrics are critical in determining rider type and prescribing workouts. A high-intensity session for one rider with the same FTP as another may be too hard, or not hard enough; 4DP provides a more complete picture.