This training plan will prepare you for a successful half- Ironman finish in 20 weeks. It will be a good fit for you if your half-Ironman goal is more ambitious than just finishing, yet time efficiency is very important to you in your training. The Level 3 plan is 20 weeks long. It begins with an 8-week base phase, followed by a 6-week build phase and a 6-week peak phase. Odd-numbered training weeks include 3 swims, 3 rides, and 3 runs. Weeks 2, 6 and so forth include 3 swims, 2 rides, 3 runs, and a bike-run brick workout. Weeks 4, 8 and so forth include 3 swims, 3 rides, 2 runs, and a bike-run brick. Every fourth week is a recovery week. Optional tune-up triathlons are scheduled in Week 12 (sprint) and Week 16 (Olympic distance). The final 10 days of each plan constitute a tapering period. The Level 4 plan begins with 4,900 yards of swimming, 3 hours 55 minutes of cycling, and 2 hours and 15 minutes of running in Week 1. It peaks with 8,000 yards of swimming, 7 hours and 5 minutes of cycling, and 3 hours and 53 minutes of running in Week 17.