Phoenix Road 5K · Sat Jan 23 2027 · sea level, flat
SUB-18 BLOCK
18 weeks · 441 miles · peak 32 mi/wk · from 18:55 (Jan 24 2026, 28th of 7,424) to 17:55 · volume first, then intensity
The Eighteen Weeks
This Week's Split—
Lift
Run
Rest
Goal Paces — The Sub-18 Math
Your Paces · Ogden ~4,500 ft, and at sea level
| Effort | Here | Sea level |
|---|
| Easy | 8:30–9:15 | 8:20–9:05 |
| Threshold | 6:44–6:56 | 6:37 |
| Interval | 6:12–6:26 | 6:07 |
| Goal 5K | 5:55–6:08 | 5:46 |
| Stride | 5:30–6:00 | 5:25–5:50 |
You train at altitude and race at sea level, which hands back 6–8 s/mi on the day. Hitting 5:55–6:08 on the Week 17 tune-up is sub-18 in Phoenix. Do not chase a faster number at home.
Where 55 Seconds Comes From
| Source | Worth |
|---|
| First-mile discipline | 8–12 s |
| VO2max — never trained | 25–30 s |
| Cadence 169 → 177 | 8–12 s |
| Racing shoes under 300 mi | 5–10 s |
| Total available | 46–64 s |
Target is 17:55, not a round number, because it is the sum of four specific things. Three of them cost nothing but attention.
The Ladder · 4 Rungs to Sub-18
| Checkpoint | Target |
|---|
| Jan 24 2026 · baseline | 18:55 @ 12 mi/wk ✓ |
| Wk 11 · Nov 30 · 2×15 tempo | hold 6:44–6:56 both blocks |
| Wk 16 · Jan 4 · 5×1000 | rep 5 = rep 1, no fade |
| Wk 17 · Jan 12 · tune-up | 3×1 mi in 5:55–6:08 |
| Race · Jan 23 | 17:55 = 5:46/mi |
The premise: you ran 18:55 on twelve miles a week with three weeks of pace work. Nobody running 18:55 off 40 mi/wk has this much left. The gain is available because you are undertrained, and this block spends 441 miles buying it — more than your entire 2026.
Jan 24 2026 · the race this replaces
| Split | Pace | HR |
|---|
| Mile 1 | 6:21 | 158 |
| Mile 2 | 6:23 | 172 |
| Mile 3 | 6:13 | 174 |
| Finish | 6:17 | 180 max |
Negative split, HR still climbing at the line, 98% of max. Same signature as Snowbasin, where mile 17 was your fastest of the day. You under-spend the opening third of every race. That is the cheapest 10 seconds in the plan.
Training Paces by Sessionflat road or treadmill · altitude-adjusted
| Session | Pace | HR | Feel |
|---|
| Easy / recovery | 8:30–9:15 | <142 | Full conversation. 80% of the block. |
| Long run | 8:15–9:00 | 142–155 | Steady. Last 15 min can drift faster. |
| Tempo / threshold | 6:44–6:56 | 156–168 | One short sentence, not two. |
| 1000m intervals | 6:12–6:26 | 169–178 | Three or four words. Full recovery. |
| Strides | 5:30–6:00 | n/a | 20 s, relaxed, cadence 175–180. |
Rules of the Block
- Never stack the stressors. Volume Oct–Nov, intensity Dec–Jan. You are more than doubling mileage and adding hard running for the first time. Doing both at once is how this becomes an injury in week 10 instead of a PR in week 18.
- Easy has to be easy: 8:30–9:15, HR under 142. It will feel absurdly slow to someone who races at 6:05. Running easy days at 8:00 is the single most common way a block like this fails.
- Two sessions are sacred: Tuesday quality and Saturday long. Everything else flexes. If a week has to shrink, cut Sunday first, then Monday.
- The long run stays at 90 min. It looks unnecessary for a 19-minute race. It is what makes the threshold work possible, and it is the only thing keeping Snowbasin open for September without rebuilding from scratch in March.
- Buy racing shoes in November. The Adizero have 585 miles across 136 activities; foam and plate are done between 250 and 350. New pair needs 30–50 mi of break-in. Use them for the tune-up and one interval session, nothing else.
- Mile one is the job. Jan 2026: 6:21 / 6:23 / 6:13. Sep 2026: fastest mile of a 17-mile race was mile 17. You finish with something left, every time. On race day the first mile goes out at goal pace, not under it.
- Cadence is the metric on strides, not pace. 175–180 steps/min. You ran the 5K at 166–172 and only hit 185 in the finishing straight.
- Upper lifting untouched — Mon and Thu. It is likely why you have stayed healthy on low mileage. Do not trade it for miles.
- Tripwire: resting HR +7 bpm, or two straight days of dead legs → convert the week to easy. Any sharp tendon pain → 2 days off running, lifting continues.
- Fuel the ramp. No deficit weeks while volume is climbing. A 5K block is short enough that there is no reason to diet through it.
Heart-Rate Zones · Max 183
| Zone | HR | Use |
|---|
| Easy | < 142 | Recovery, 80% of miles |
| Steady | 142–155 | Long run |
| Threshold | 156–168 | Tuesday tempo |
| Interval | 169–178 | 1000s only |
| Race 5K | 165–180 | Jan 24 2026 avg was 168 |
Gate · Tue Jan 12: tune-up 3×1 mi at 5:55–6:08.
All three in the band with mile 3 fastest → race sub-18 and go out at 5:46.
Drifting past 6:15 → race 18:15–18:30 honestly and bank the base for Snowbasin.
On the Fenix · sync Garmin Connect
| Workout | Weeks |
|---|
| MAGNI 5K · Tempo | 5–11 |
| MAGNI 5K · 5×1000 | 13–16 |
| MAGNI 5K · Easy + Strides | every week |
| MAGNI 5K · Tune-up 3×1mi | 17 |