Running Plan Review Buena Vida Run Club's 16-Week Sub-3:45 Marathon (5 days)
Who’s behind this review? Buena Vida is a running app made by David Cole, a Seattle runner & triathlete who led design and research for Amazon’s Halo fitness band. This is one of Buena Vida’s own plans, so we have an obvious interest in how it compares. It’s scored on the same 30 measures as every plan we review, each tied to published research, and its weaknesses are published below. AI does the first scoring and draft, then every claim is checked against its studies. No plan author pays to be reviewed, and we run no ads. See a mistake? Email David at corrections@buenavida.run · How we score →
Plan at a Glance
A sub-3:45 marathon asks for a pace that sits below the effort most runners expect. At this goal, marathon pace is slower than threshold, the effort you could race for about an hour. The plan is a careful 16-week build for a runner who has finished a marathon or a few halves and already runs around 37 miles a week over five days.
Marathon coach Luke Humphrey, co-author of the Hansons Marathon Method, puts it plainly: over longer distances, "our race may not even be approaching our lactate threshold." This plan uses that fact its own way: its hard days go into threshold runs and faster reps, so goal pace shows up only a few times, as rehearsal. The long run stays conversational and tops out at 18 miles, in a peak week near 50.
The catch is the easy days. The day that decides most weeks is the one after the session. A few miles into that medium-long run the legs come round, the watch starts creeping, and a steadier effort starts to feel more useful. Let it creep and the weekend starts tired. Keep it easy enough to talk through and the week works. If you run well under 37 miles a week now, build toward it for 2 or 3 weeks before you start.
Below is Buena Vida's full review of the plan. We score every plan against our detailed, 30-point benchmark. Each measure is drawn from peer-reviewed sports-science research and proven coaching best practices.
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Our Review
Chasing a 3:45, the natural instinct is to run a lot of miles at 3:45 pace. It's a fair instinct, especially if you came up through the half marathon, where race pace sits nearer threshold. At this goal they come apart. Marathon pace sits well below threshold, so a race-pace run and a threshold run are different kinds of training, and neither has been shown to beat the other. This plan puts its hard work into threshold runs and faster reps, and keeps goal pace for rehearsal, a sound choice here. Around that, the build is careful, with a lighter week about once a month and a taper that trims the miles but keeps the speed.
It's an easy plan to recommend. Every Tuesday has a clear job, and easy running fills the days on either side of it. The three things to plan around are small: the long run peaks early and only once, week 7 brings the sharpest rise in load, and the first standalone goal-pace run arrives just as the volume climbs back out of a cutback. None of these asks you to rewrite the plan, only to know where the pressure sits. The rest is up to you. If your easy days tend to drift faster because slow feels wasted when you have a number to hit, this plan asks you to let them be slow.
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Structure
Does the plan build you up smartly?
Patiently. The plan moves through base, build and taper, and each block has a job you can see. The opening month leans on threshold runs, the middle weeks bring in faster reps at 5K and 10K pace, and the final stretch returns to threshold with goal pace as rehearsal. Every hard session comes written out, with easy miles before and after the work and a note on what it is for. The threshold work grows a mile or a format at a time, so each Tuesday asks only a little more than the one before.
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Prevention
Does the plan protect you from injury?
From the first week, with every session wrapped in easy miles. Even week 7's 3 × 2 miles opens with 2 easy miles and closes with 1.5, and Wednesday's medium-long run keeps the day after the session easy. Each lighter week, about once a month, trims every day but keeps one short session, so the hard effort stays familiar. "Athletes often feel sluggish and have lower energy during this week," says coach Pete Rea, who cuts his runners back every third week. "Nonetheless I find the level of workouts is elevated thereafter." The plan leans on easy running even more heavily than the ideal mix: Tuesday is the one quality day, and everything else is yours to keep slow. Three weeks deserve a closer eye. Week 7 is the steepest rise in load, with the first cruise intervals, an 11-mile Wednesday and a new longest run all landing in the biggest week so far. The first threshold run arrives in week 2 as the week grows, and the first standalone goal-pace run arrives as you come out of the last cutback of the build. Run those first sessions controlled rather than proud. Many running injuries seem to start suddenly, often right after a run that goes well past your recent longest, so if new pain shows up, look at the last week or two first. A niggle that lingers is worth a few lighter days rather than grit.
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Flexibility
What happens when you miss a day?
Protect Tuesday and Saturday above all, because the session and the long run carry each week. Monday's recovery run and the Wednesday medium-long run come next, and the Friday easy run and the strength slot are the first to give. If you miss the session, run it Wednesday in place of the medium-long run, never on Friday, the day before the long run. If you miss Saturday, Sunday is open, so run it a day late or let it go rather than folding it into the next week. After a missed week, rejoin the plan at the current week rather than the one you lost, and trim that first week back to the size of a cutback such as week 8. Coming straight back to full volume after a week off is a jump your legs haven't been prepared for.
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Readiness
Will the plan deliver race-day fitness?
Ready for the distance, on a build shaped for it. At this goal, marathon pace sits below threshold, so the plan spends its hard days on threshold runs and cruise intervals and treats goal pace as a rhythm to learn. It rehearses that rhythm three times: a block inside one long run, a 5-mile pace run after the last cutback of the build, and a 2-mile touch in race week. A peak of about 50 miles suits the distance. The taper keeps a threshold run, 5K-pace reps and strides while the miles drop over the last three weeks, the kind of taper that improves race performance over holding the load steady. Olympic marathoner Des Linden has said why she won't cut too far: "The body craves consistency, and if I cut back too much I'll end up feeling lethargic and flat." The long run is the soft spot. It reaches 18 miles once, five weeks before race week, and the final month tops out at 16. Most marathoners count the long run as the session that readies them for the closing miles, and here race morning takes you well past anything recent. If your last marathon came apart in the closing miles, this is the gap to take seriously, and the fix under what's missing is meant for you.
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Variety
Are the workouts varied enough?
The midweek session keeps changing. It rotates through continuous threshold runs, cruise intervals of 3 × 2 miles, 800s at 5K pace, 1000s and 1200s at 10K pace, a hill session of 6 × 200 m, and two goal-pace runs. Strides finish an easy run in most weeks, and the Wednesday medium-long run gives the week a second run of real length without a second hard day. Running writer Kevin Beck describes runs like this as "basically everyday runs sustained for an extra 30 to 60 minutes. They aren't recovery runs, but they aren't hard and should not require special recovery." Strides keep short, fast running familiar, and they cost almost nothing. The variety also has a direction. Each format belongs to one of two strands, threshold or faster reps, so the session changes from week to week while the purpose holds.
Workouts
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This week sits close to the running you already do, and that is deliberate. Nothing here asks you to prove anything. The weeks ahead settle into a pattern of a pair of harder days with easy days around them, easy enough to talk through. That easy running is most of what a marathon is built on, so its slowness is the point rather than a flaw. Notice how the runs fit into your days, because the routine has to last 16 weeks.
M 4.5mi Recovery Run
4.5 miles at recovery effort. The plan opens with a short, gentle run at a volume close to what you already do. Mondays follow the weekend and come before Tuesday, so they stay slow every week. Let the pace be whatever feels like jogging with a friend.
Tu 7mi Easy Run with 4×100m Strides
6.5 miles easy, then 4 strides of 100 m with a walk back after each. Strides are short bursts that build to quick without straining. They keep fast, smooth form in the legs. Most Tuesdays hold the harder session of the week. This one stays easy, so the week sits close to the running you already do. Stay tall and loose on every stride.
W 8mi Medium-Long Run
8 miles at an easy, conversational effort. The Wednesday medium-long run gives the week a second run of real length without a second hard day. The plan's longer running starts here, midweek, a few days before Saturday. It also sets a new high for distance, which Saturday then extends. Keep the pace even and unhurried from start to end.
Th Strength Training
F 5.5mi Easy Run
Easy 5.5 miles, your last single before the weekend long run. Keep the effort low and the breathing comfortable. Think of this run as setting up tomorrow rather than as a workout of its own. The aim is to arrive at the long run with fresh legs, not to squeeze extra fitness out of today. Slow is the point here, not a compromise.
Sa 12mi Long Run
12 miles easy and steady. The long run is one of the week's 2 hard days, and its difficulty is the distance, never the pace. It is the furthest the plan has asked of you so far, at a distance close to your usual weekend run. Long runs here grow slowly and top out by time on the clock rather than a set number of miles. Settle into a pace you could talk at and hold it, even if the closing miles feel easy.
Su Rest
Harder running enters the week, and one day of sustained effort changes how the days around it feel. Heavy legs or a dull ache the day after is ordinary and fades within a day or so. It can be tempting to skip or speed up the easy days once real effort arrives. Those easy days are where that effort pays off, so keep them slow even when they feel too short to matter. Judge the week as a whole rather than any single day.
M 4.5mi Recovery Run
4.5 miles of recovery running after the weekend. Tomorrow holds a sustained harder effort, so today exists to deliver fresh legs to it. Keep the stride short and the breathing easy enough to hum along to music.
Tu 7mi Threshold Run with 3mi @ Threshold
Warm up for 2 miles, run 3 miles at threshold pace of 8:11/mile, then cool down for 2 miles. Threshold is the effort you could race for about an hour, hard but steady enough to hold without strain. This run starts the threshold work that carries through the plan. At this goal, 8:32/mile sits well below threshold, so the two are different kinds of training. The continuous segment grows over the coming weeks, and later it splits into longer repeats with short jogs between. Start the segment controlled and finish it at the same pace, never faster.
W 9mi Medium-Long Run
9 miles easy, the day after the threshold run. Tuesday's effort lingers in the legs, and a long, gentle run moves it along while still adding real distance. If the pace creeps toward steady in the later miles, ease it back.
Th Strength Training
F 7mi Easy Run with 4×100m Strides
6.5 miles easy with 4 strides of 100 m to finish, walking back between them. The strides are short, relaxed practice at running fast at almost no cost, which is why they return on easy days most weeks. Build speed over each one rather than bursting off the line. They also leave the legs feeling light for Saturday.
Sa 13mi Long Run
13 miles at an easy, even effort. That is a step beyond the Saturday before and the furthest run of the plan so far. Steady long runs at this effort build the endurance a marathon leans on, and they leave enough in reserve to train well on Tuesday. Keep checking that you could still chat in full sentences, and slow down if the answer changes.
Su Rest
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Plan Strengths
- The hard work targets threshold, the effort that moves a sub-3:45 goal, and leaves goal pace as rehearsal.
- A lighter week about once a month, each one keeping a short session so the effort stays familiar.
- Each Tuesday session is bracketed by easy running, as much as 2 miles before and 2 after the 5-mile threshold run in week 9.
- An easy medium-long run the day after the session adds a second run of real length without a second hard day.
- A taper that drops the miles over three weeks but keeps a threshold run, 5K-pace reps and strides.
Weaknesses & Gaps
- The long run peaks once, five weeks before race week, and the final month tops out at 16 miles.
- Week 7 is the steepest jump in load, with several new demands landing in the biggest week so far.
- The first standalone goal-pace run arrives as volume climbs out of the last cutback of the build, and the first threshold run lands in a growing week 2.
- The mix leans on easy running even more than it needs to, with one quality session a week.
What's missing
One more long run near peak distance would round out the build. If the 18-miler goes well, you could run the long run after the last cutback of the build at 17 or 18 miles instead of 16. That is a deliberate trade, because it lands in the same week as the first standalone goal-pace run, so if you take it, run that Tuesday gently and let Saturday be the week's real effort. The plan also skips a tune-up race, a defensible choice, since no study has tested whether tune-ups make the marathon itself faster. If you want one anyway as pacing practice, a half marathon at marathon effort can stand in for the long run that already carries a goal-pace block. Know the cost: it is far more goal-pace running than that day asks for, in the same week as the longest threshold run, so keep the rest of that week easy. And if your course rolls, move some Wednesday and Saturday easy miles onto rolling routes so the climbs on race day feel familiar.
What the science supports
Shifting training emphasis beats unchanging training
The plan moves through three clear phases: an eight-week base, a five-week build, then a three-week taper. Planned shifts in training emphasis tend to beat holding the same training throughout, though in the one trial of well-trained runners the gain was small. Coaches of world-class runners shift toward race-specific work as the race nears, and this plan does the same, saving its goal-pace runs for the build and taper.
Filipas et al. 2021; Bradbury et al. 2020; Sandbakk et al. 2025
Longer long runs go with faster marathons
Long runs climb steadily from 12 miles to an 18-mile peak in week 11, with the longest efforts running well past 2 hours for most runners at this goal. Early evidence links longer long runs with faster marathon finishes, though no study has tested whether shorter, harder sessions could do the same job. Most runners find these are the runs that show them what the late miles of a marathon feel like.
Doherty et al. 2020; Fokkema et al. 2020; Toresdahl et al. 2022
Easy miles do most of the work
Close to 90 percent of the running in this plan is easy and conversational, slow enough to talk in full sentences. Distance runners at every level keep most of their running at that effort, and recreational runners use the same balance at lower mileage. The threshold runs, intervals and goal-pace work make up the rest. The easy miles build the aerobic base that the Tuesday sessions and Saturday long runs stand on.
A real taper sharpens you for race day
The final three weeks pull volume down step by step while keeping a 3-mile threshold run, 5 × 800 m at 5K pace and 2 miles at goal pace in the legs. A taper of up to three weeks improves race performance compared with not tapering at all. Cutting volume while a little intensity stays in is the pattern behind that finding.
Strength training makes running more efficient
A strength session sits on the calendar every Thursday from week 1 through week 15. In trained distance runners, strength work improves running economy. That means the legs use less energy at the same pace. The gain comes from the muscles and tendons rather than the heart and lungs. The slot sits between the medium-long run and an easy Friday, clear of the hard days.
Blagrove et al. 2018; Balsalobre-Fernández et al. 2016; Šuc et al. 2022
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