Skip to main content
English · Español

2026-05-24 · 4 min read


Sub-40 10K plan — the ideal week (with the reasoning behind every session)


Going under 40 minutes for 10K is both a symbolic goal and a very concrete one. You need to average 6:25/mile (3:59/km) for the whole thing. Here's the week the Vetta engine prescribes when somebody is training for sub-40 — with the logic behind every session.


The assumptions


Before the week, let's assume:


  • Current VDOT ≈ 52-53 (if you're running 43:00 today, your VDOT is 47-48 — the priority is getting that number up first).
  • Base mileage: 30-40 mi/week (50-60 km). Less than that and you'll come up short on aerobic).
  • Time since last injury: if it's been 6+ healthy months, we can push quality. Coming off a layoff? Rebuild first.
  • No marathon or half goal in the same block: this plan is 10K-specific.

    • The model week (40-45 mi / 60-70 km, 6 sessions)


    ### Monday — Off or recovery jog (0 or 30')


    After a loaded weekend, you reset. TSB below -15 → full rest. TSB between -10 and -5 → 30' Z1 jog (HR under 70% of max).


    Why: rest is where adaptation happens. Without rest, no progress — just attrition.


    ### Tuesday — VO2max quality (60' total)


  • 15' warmup + drills.
  • 6 × 1000m at 5K pace (~6:10/mi, 3:50/km) with 90" jog recovery.
  • 10' cooldown.

    • Why: lifting the ceiling — pushing your VO2max. Long reps (1000m) are the building block for sub-40, not the short stuff. At that intensity you're hitting the system that sits furthest from your current level.


    ### Wednesday — Easy aerobic (50-60 min Z2)


    Steady jog at conversational pace (7:45-8:20/mi, 4:50-5:10/km), flat or rolling terrain.


    Why: filling in aerobic volume without piling on fatigue. Z2 expands capillarization, improves fat oxidation, and primes the legs for Thursday's quality.


    ### Thursday — Threshold / tempo (55-65 min total)


  • 15' warmup.
  • 2 × 15 min at threshold pace (~6:42/mi, 4:10/km), with 4-5 min jog between.
  • 10' cooldown.

    • Why: threshold pace is the most "bang for buck" pace for 10K. Holding that pace lifts your *lactate threshold* — the ceiling above which lactate piles up. For sub-40 you want a threshold close to 6:25/mi (4:00/km).


    Variant: cruise intervals (3 × 10 min at threshold with 2' jog) feel slightly easier mentally.


    ### Friday — Off or cross-train (0 or 30-40' Z2 spin)


    If your accumulated load is running hot, full rest. If you want aerobic time without impact, 40' easy on the bike (no more).


    Why: loading well for Saturday's long. Two days back-to-back of quality breaks most people.


    ### Saturday — Long run with fast finish (75-90 min)


  • 60-75 min Z2 jog (7:45-8:00/mi, 4:50-5:00/km).
  • Last 15-20 min progressive, closing the final 5 min at marathon pace (~6:58-7:15/mi, 4:20-4:30/km).

    • Why: the long run is still the foundation for the 10K — not just the marathon. The fast finish teaches your body to run quick on tired legs, which is exactly what km 8 of the race feels like.


    ### Sunday — Recovery or shake-out (30-45 min easy jog)


    Very easy jog, almost a brisk walk in feel (8:35-9:05/mi, 5:20-5:40/km), aiming to keep the legs fresh going into Monday.


    Why: shake-out runs actually boost recovery. If TSB is buried, full rest is fine too.


    Intensity split


    If you add up the time:


    | Zone | Approx time | % |

    |---|---|---|

    | Z1 (recovery) | 30-45 min | 8% |

    | Z2 (aerobic) | 150-180 min | 60-65% |

    | Z3 (threshold / tempo) | 30 min | 10% |

    | Z4-Z5 (VO2max) | 30 min | 10-12% |

    | Other (gym, drills) | varies | — |


    It lands as a pyramidal split with a polarized lean. Drop Z3 to almost nothing and bump Z4-Z5 and you get classic polarized (80/20). For 10K, pyramidal beats pure polarized — you need work at race-effort (Z3).


    The 12 weeks


  • Weeks 1-4 (Base): this layout with rising volume. Quality on Tuesday + Thursday only. Long run growing 5-10' per week.
  • Weeks 5-8 (Specific): Tuesday shifts to longer reps (3 × 2000m at 10K pace + 5 × 1000m to close the block). Saturday adds fartlek surges.
  • Weeks 9-10 (Peak): drop in a "tune-up race" (5K or 8K) to recalibrate VDOT and the head.
  • Week 11 (Taper): -25% volume, quality stays.
  • Week 12 (Race week): -50% volume. One short activation session (3 × 800m at 10K pace) on Wednesday. Saturday off. Sunday, race.

    • Common mistakes


    1. Too much quality, not enough aerobic. Reps-only and you'll stall. The aerobic base is 60-70% of the total.

    2. Skipping the easy day. Wednesday's "easy" isn't optional — it's what lets Thursday's quality go hard.

    3. Ramping too aggressively. More than +10% volume week-over-week = injury territory. Vetta caps at +8%.


    Vetta


    The [Vetta](/signup) engine periodizes this logic automatically. You mark "10K, sub-40, target date", connect Strava, and it builds weeks around this skeleton — adjusting volume and intensity by your real CTL and your safe ramp. If you want to try it, [start here](/signup) — first month Pro on us.