Case Study: Cesar's First Half Marathon Build — What the Data Actually Shows

Why I'm Sharing Cesar's File

Every few months I pull an athlete's training log and just sit with it — no narrative, just the numbers — before I decide what story it's telling. I don't start with the athlete's version of events. I don't start with how the training "felt." I start cold, with a spreadsheet, and I let the pattern reveal itself before I let anyone tell me what it means. Cesar's file from this spring and summer is a good one to share publicly because it's unglamorous. Thirteen sessions logged over thirteen weeks, a longest run of 19.5 km, a total volume of 171.1 km. Nobody is going to mistake this for an elite half marathon build. There's no double-digit weekly mileage, no back-to-back long runs, no altitude camp, no fancy periodization language. But that's exactly the point.

I could have picked a flashier file. I coach athletes who log 80 km weeks and I could show you a build with heat maps and power curves that make for a prettier chart. But those files don't teach anything most runners can actually use, because most runners aren't operating in that world. Most runners preparing for a debut on half marathon — or in Cesar's case, what looks like a debut half or a serious 10-mile-to-half build — aren't overtraining. They're undertraining, then panicking, then cramming three weeks of missed volume into ten days because the race is looming and the guilt is louder than the training plan. That's how people get hurt four weeks out from race day, and it's the single most common failure mode I see in amateur endurance training. Cesar's file shows a different pattern: a slow, deliberate ramp with a real peak, a real taper, and an honest gap in the middle that I want to talk about instead of hide.

That last part matters to me. I could publish the clean version of this story — the version where every week ticks up nicely and the athlete is a model of consistency. It would be a better advertisement. It would also be a lie by omission, and it wouldn't help anyone reading this who has looked at their own log, seen a missed week, and concluded that the whole build was ruined. It wasn't ruined. Keep reading.

The Shape of the Build

Here's the weekly progression, starting the week of April 27, 2026:

Week of	Sessions	Distance	TSS	Longest Run
Apr 27	1	11.5 km	251	11.5 km
May 4	1	11.5 km	—	11.5 km
May 11	1	13.5 km	97	13.5 km
May 18	1	15.5 km	344	15.5 km
May 25	1	17.5 km	—	17.5 km
Jun 1	1	2.1 km	—	2.1 km
Jun 8	1	19.5 km	414	19.5 km ← peak
Jun 15	1	19.5 km	—	19.5 km ← peak
Jun 22	1	17.5 km	333	17.5 km
Jun 29	1	15.5 km	341	15.5 km
Jul 6	1	13.5 km	—	13.5 km
Jul 13	1	11.5 km	254	11.5 km
Jul 20	1	2.1 km	491	2.1 km

Total across the window: 171.1 km, 2,525 TSS, all logged as Run sessions. Longest single effort: 19.5 km.

The shape is a clean pyramid. Build from 11.5 km up to 19.5 km over six weeks, hold the peak for two weeks, then descend symmetrically back down. That's not an accident — it's the classic load-and-unload structure that shows up in almost every well-designed endurance progression, whether you're coaching a debut half-marathoner or a masters 10K runner. You can see it if you trace just the "Longest Run" column with your finger: 11.5, 11.5, 13.5, 15.5, 17.5, dip, 19.5, 19.5, 17.5, 15.5, 13.5, 11.5, dip. Ignore the two outlier weeks for a second and what's left is almost architecturally symmetric — a six-step staircase up, a two-week plateau, a five-step staircase down. Most self-coached runners never build anything this deliberate. They build until they're tired, hold until they're bored, and taper until they panic.

The TSS numbers, sparse as they are, tell a consistent side story. Where we have data — April 27 (251), May 11 (97), May 18 (344), June 8 (414), June 22 (333), June 29 (341), July 13 (254), July 20 (491) — the load rises in step with distance almost everywhere except May 11, where 13.5 km produced only 97 TSS, suggesting a genuinely easy effort, probably recovery pace, nested inside a week that was otherwise building volume. That's a detail worth noticing: not every long-ish run in this plan was run hard. Some of the distance increases were volume for volume's sake, banking aerobic time without adding fatigue. That's good coaching, whether Cesar was self-coached or not, because it means the body was allowed to adapt to time-on-feet before it was asked to adapt to intensity.

The taper isn't a cliff, either. It's a staircase down, mirroring the staircase up almost step for step — 17.5, 15.5, 13.5, 11.5 — before dropping to a shakeout 2.1 km the week of the race itself. That symmetry isn't cosmetic. Tapers that fall off a cliff (cutting volume by 70-80% in one week) tend to leave athletes feeling flat and heavy-legged on race day, because the body doesn't have time to recognize the new, lower stress level as the new normal. A staircase taper lets the nervous system and the muscles down gently, which is exactly what you want three weeks out from a goal race.

The Week That Matters Most: June 1

I want to flag the week of June 1 specifically, because it's the one anomaly in an otherwise disciplined progression: a single 2.1 km session, down from 17.5 km the week before. That's not a small dip — it's a 88% drop in weekly volume, right in the middle of the build phase, at a point where the plan was still climbing toward its peak.

This is a real gap — whether it was travel, illness, work, or life getting in the way, I don't fabricate a reason where the data doesn't give me one. I've seen this exact shape in dozens of files: a runner gets sick for four days, or a work trip eats the week, or a kid gets sick and the 6 a.m. long run turns into a 20-minute jog around the block just to keep the streak alive. I don't know which of these happened to Cesar, and I'm not going to pretend the log tells me. What I can tell you is how the plan responded, and that response is the actual lesson here.

Instead of trying to make up the missing volume — instead of the classic panic move of tacking an extra 5 km onto the following week to "catch up" — the very next week, June 8, picked back up at 19.5 km. That's not a modest, cautious return. That's a jump straight to what would become the peak of the entire build, and it worked, because the six weeks of aerobic base that came before the gap were still intact. One missed week didn't erase five weeks of adaptation. The body doesn't work like a bank account that empties the moment you stop making deposits — fitness has inertia, and a single short week, even a dramatically short one, barely dents it if everything around it was built properly.

This is the part I most want runners reading this to internalize: the instinct after a missed week is almost always to punish yourself for it in the training log, to try to "earn back" the lost kilometers by cramming them into the next available slot. That instinct is almost always wrong, and it's how normal, forgivable setbacks turn into overuse injuries. Cesar's plan — or Cesar's coach, or Cesar's own good judgment — did the opposite. It treated the missing week as a non-event and simply resumed the plan where it would have been anyway. No make-up long run. No doubled-up week. Just a return to the staircase, one step at a time, straight into the two-week peak that followed.

What This File Actually Teaches

Strip away the specific numbers and Cesar's build reduces to a handful of principles that apply well beyond this one runner: build gradually over six-plus weeks rather than in a rush, hold the peak long enough for it to register as a real stimulus rather than a single heroic effort, taper as a mirror image of the build rather than a sudden collapse in volume, and — most importantly — treat an inevitable missed week as noise, not signal. One short week in a thirteen-week block, positioned in the build phase rather than in the final taper, is not a crisis. It's not even really a story. It's just what real training looks like when it's lived by an actual human being with an actual job and an actual life outside of the log.

That's why I'm sharing this file instead of a cleaner one. The clean files are inspiring for about five minutes and useless after that, because nobody's training block actually looks like a perfect diagonal line on a chart. Cesar's does what I want every athlete's file to eventually do: it shows a real gap, survived without drama, inside a structure solid enough to absorb it.