A half marathon rewards runners with a stable aerobic engine and a threshold pace they can hold for roughly 90 minutes. Reshape’s half plan builds both across twelve weeks, grows the long run at a cap that protects you from overreaching, and rebuilds each week from the runs you actually logged.
Twelve weeks in three phases
Weeks one through four are base. Mostly easy running, one weekly threshold session, and a long run that extends one step at a time. The job is aerobic capacity: making your body efficient at burning fuel at low intensity.
Weeks five through eight are build. Threshold work gets longer, VO2Max intervals appear, and the long run stretches toward 18–22 km. This is where race-pace awareness starts. Some long runs end with a short segment at half-marathon pace so race day feels like something your body has practiced, not something it has to figure out in the moment.
Weeks nine through twelve are peak and taper. The highest-quality sessions live here, then volume pulls back sharply in the final fortnight so you arrive rested. The taper is a real two weeks, not a three-day token one.
Three half-marathon runners this plan fits
- First half. If this is your first time racing the distance, the plan prioritizes getting to race day healthy. Long runs extend gradually. Threshold sessions are moderate. Finishing, not racing, is the job.
- Going sub-two, sub-1:45, sub-1:30. If you have a specific time in mind, Reshape uses VDOT to scale interval and threshold paces to your current fitness. The block is built around the race date and the taper is protected.
- Building toward the marathon. A good half is often the cleanest way to evaluate marathon readiness. The plan can roll into a marathon block once the half is done, carrying over your current VDOT and accumulated base.
What a peak half week is built around
A peak-phase half week typically has four or five days of running, balanced so the hard sessions have real recovery between them. Inside a normal week:
- One threshold session. Sustained time at the pace you could hold for roughly an hour. The strongest predictor of half-marathon performance for most runners.
- One interval session. Shorter reps at 5K-to-10K effort. These keep the top end sharp so race pace feels controlled.
- One long run. Grows across the block at a pace your body can absorb. Some weeks finish with a segment at race pace once the aerobic base is solid.
- One or two easy runs. Short, conversational, recovery-paced.
The specific paces, session lengths, and rep counts are composed by Reshape from your current VDOT and the phase of the block. A rough week pulls back; a strong week adds load carefully. Week-to-week load changes are capped so long runs never jump far enough to injure you.
Built on what you already ran
- Reads Apple Health. Up to eight weeks of running history, including VO2 Max, pace, mileage, recovery signals.
- Workouts on Apple Watch. Each session lands on the watch the night before with pace targets on the face.
- Weekly regeneration. The next week is rebuilt from what you completed, with specific caps on how much week-to-week load can change.
Reshape isn’t the right pick if…
- You want a human coach in the loop. Reshape is software only.
- You want strength and Pilates programming in the same app. Reshape is running-only. Runna has a library for that.
- You train on Android, Garmin, Coros, or Fitbit. Reshape is iPhone and Apple Watch only.
Common questions
Twelve weeks is the standard. Eight is possible if you already have a steady 40–50 km per week base. Sixteen or more makes sense for first-timers or anyone building volume from a lower starting point. Reshape reads your Apple Health history and sets the starting week to match your actual current mileage, not a theoretical one.
For most runners preparing a half, the long run grows from around 10 km in early base to 18–22 km by late build. It’s run at a conversational pace. Occasionally the plan finishes a long run with 20–30 minutes at marathon or half-marathon pace once the base is solid. Jumping the long run more than about 20% week-to-week is the fastest way to pick up an injury; the plan caps that by default.
For a finish-time-first goal, anywhere from 35 to 60 km per week in peak weeks is common. First-timers can race a half at 30–40 km a week of mostly easy running. Runners chasing a PR usually sit at 50–80 km in peak weeks. Reshape caps week-to-week load changes so volume builds without spikes your body can’t absorb.
Yes. Reshape sends each workout to your Apple Watch the night before with pace targets on the face, and the session is recorded on the watch. iPhone is where you see the plan, read the coach notes, and log completion after each run; Apple Watch is how you actually run the sessions. Reshape is iPhone and Apple Watch, not iPhone alone.
Yes, and this is one of the places a plan that reads your actual history helps. If Apple Health shows you’ve been doing a lot of short-interval work but not much volume, the early weeks focus on building easy aerobic minutes before the long run extends. The goal is to reach race day with a long run close to race distance and legs that have been protected from overreaching.