Description McDuffie consists of 5 sets of "sprint-ervals" each comprised of 3x12-second sprints at 200% FTP followed closely by a slightly suprathreshold, 4-minute effort at 105% FTP. Recoveries between sprints are about 50 seconds long, and the recoveries between sets are 3 minutes each. Goals McDuffie's primary objective is to increase muscle fiber recruitment via the use of all-out sprint efforts and secondarily reap the reward of this additional muscle activity to power through a demanding, leg-searing 4 minutes of work slightly above Functional Threshold Power (FTP). So, both neural activation as well as muscular endurance are targeted in each tidy set of sprints + intervals. Recovery following the sprints is minimal and won't allow complete recovery while recovery between sprint-ervals is 3 minutes long with the intention of allowing just enough rest to effectively repeat these challenging sets. Sprint-ervals aim to increase fiber recruitment via short, powerful, pre-interval sprints such that the subsequent supra-threshold intervals feel more manageable as a result of more muscle activity. Keep your spin well above 100rpm during the sprints and closer to 90rpm during the longer, subsequent stretches.