BWhy the Base block still looks this easy when your legs remember running 1,000 miles last year
Strength and endurance detrain and retrain on genuinely different clocks, and both cut against starting hard right now.
On the lifting side, "muscle memory" is real and mechanistic, not just a phrase: myonuclei and satellite cells added during earlier training appear to persist through a layoff, giving retraining a head start over a true first exposure. The clearest controlled data on this comes from older adults (12 weeks training, 12 weeks detraining, 12 weeks retraining) rather than a population that matches you exactly, so treat the mechanism as well-supported and the exact timeline as a reasonable guess, not a number to plan around.
On the running side, the effect is closer to the opposite. A 24-month study in competitive runners found injury risk rose specifically when the acute:chronic workload ratio increased quickly — i.e. when training resumed faster than the body's recent average could absorb. Tendon and bone don't get a "memory" discount the way muscle does. Coming back from on-and-off running with a nonexistent current base is exactly the scenario that statistic describes, regardless of last year's mileage or how strong the lifts still feel.
Practical result: the Base block's easy volume isn't paced for a beginner and it isn't paced for someone at full fitness — it's paced to let running catch up to what the muscles already remember, not the other way around. If the lifts start feeling too easy before week 4, that is expected and not a sign the Base block needs to change.
Bloom et al., Exp Gerontol 2020;133:110860 (muscle memory mechanism; population: older men) · Dijkhuis et al., Int J Sports Med 2020 (n=23 competitive runners, 24 months)
AUpper body carrying the volume is correct — interference is body-part specific
This was the central bet of the hybrid restructure and it holds. Wilson's meta-analysis found the interference effect to be body-part specific: upper-body strength was not affected by concurrent endurance training. Sabag's 2018 meta-analysis on concurrent strength and HIIT reported the same pattern — lower-body strength attenuated versus strength training alone, upper-body strength unaffected. Endurance volume was a moderating variable: longer and more frequent endurance training correlated with greater reduction in lower-body strength and power.
So loading chest, back, shoulders and arms to 11-12 sets a week while holding legs at 9 heavy sets isn't a compromise — it's the structure the evidence points at.
Wilson et al., J Strength Cond Res 2012 · Sabag et al., 2018
ADJUSTEDThe squat had one more set than the evidence calls for
The ACSM's 2026 Position Stand — synthesising 137 systematic reviews and over 30,000 participants — found voluntary strength enhanced by lifting ≥80% of 1RM, through a complete range of motion, for 2-3 sets, at the beginning of the session, ≥2 sessions per week. Runner-specific reviews converge on the same place: 2-3 sets of 4-5 reps at about 85% 1RM.
My prescription was 4×5. Changed to 3×5 plus one back-off set of 8 — three heavy sets for the strength adaptation, one lighter set for the hypertrophy stimulus, and less leg fatigue heading into a race build. Load is prescribed by RPE (7-8 on the heavy sets) rather than a %1RM, since no 1RM has actually been tested — RPE is what the weekly log can act on. The same Position Stand also found that training to momentary muscle fatigue did not consistently improve outcomes, which is why nothing in this plan asks you to grind.
ACSM Position Stand 2026 (137 reviews, >30,000 participants) · Llanos-Lagos et al., Sports Med 2024
CORRECTEDThe Eddens citation doesn't cover the actual scheduling question here
Eddens's meta-analysis found resistance-before-endurance favoured lower-body dynamic strength over ≥5 weeks — but it only included studies with 15 minutes or less between modalities, and the authors scope the finding to people who can't separate their sessions. Nothing here runs a same-session double; every day is AM run, PM lift, hours apart. That paper doesn't actually speak to which day the heavy lift should fall on.
The real scheduling question — and the one that matters — is the between-day gap: this build used to put the heavy squat on Monday, ~36 hours before Wednesday's tempo, inside the window resistance training measurably depresses running economy (see below). Fixed by moving the heavy squat to Thursday — the only day with no run at all — and the light posterior lift to Monday. Wednesday's tempo now sits ~5 days post-heavy-squat instead of 36 hours.
Eddens et al., Sports Med 2018 · Robineau et al., J Strength Cond Res 2016
AThe AM/PM split is doing real work — not just fitting your schedule
Separating the two modalities by at least six hours meaningfully reduces acute interference: in 58 athletes over 7 weeks, a 0-hour gap between strength and endurance work blunted strength gains, while 6-hour and 24-hour gaps did not differ from strength-training-alone. The mechanism is measurable too: AMPK rises sharply after high-intensity endurance work and takes at least three hours to return to baseline, while mTORC1 activity from strength training persists around eighteen hours.
Your structure puts roughly ten to twelve hours between morning runs and evening lifts — comfortably past the 6-hour threshold. Where the real caution sits is the next day's run, not the same day's: submaximal running performance can stay measurably depressed for up to 48 hours after heavy resistance training. That's the actual reason the heavy squat now falls on Thursday (see above) rather than Monday — it puts ~5 days, not 36 hours, between the heavy squat and the next demanding run.
Robineau et al., J Strength Cond Res 2016 · Doma et al., Sports Med Open 2019
AHeavy and low-rep beats light and high-rep for runners — clearly
A comparison of heavy/low-rep, light/high-rep and complex protocols found the heavy and complex interventions produced superior improvements, while the light/high-rep version produced no distinguishable improvements despite being load-matched. Heavier, lower-rep work also generates less residual fatigue than high-rep sets, which matters when you're running five days a week. This is the direct justification for legs going 5-rep and upper body staying in the 8-12 range.
Runner-specific strength protocol comparisons · Rønnestad & Mujika, Scand J Med Sci Sports 2014
BTwo lifting sessions a week is the demonstrated minimum, and you're above it
Several studies show benefits for runners from twice-weekly strength training, and the ACSM stand specifies ≥2 sessions per week for strength adaptation. You run four — two upper, two lower. The lower frequency is what the running evidence asks for; the upper frequency is free, because that's the half that doesn't interfere.
ACSM Position Stand 2026 · runner strength-training reviews
FIXEDThe taper cut too little volume
Bosquet's meta-analysis of 27 studies found the most effective strategy is a two-week taper with training volume reduced 41-60%, without altering intensity or frequency. A later meta-analysis of 14 endurance studies confirmed it: a ≤21-day taper reducing volume 41-60% while maintaining intensity and frequency significantly improved time-trial performance, with the largest effect at 8-14 days. It also found tapering after a pre-taper overload period beat conventional tapering.
My original taper cut only 18% then 25% — well outside the effective range. Rebuilt: week 16 is now −43%, week 17 is −56%, achieved by shortening every run rather than dropping sessions. You still run five to six days and still do half-marathon-pace work, because frequency and intensity are exactly what the evidence says to hold constant. Week 15 stays as the overload peak that makes the taper work.
Bosquet et al., Med Sci Sports Exerc 2007 (27 studies) · Wang et al., PLOS ONE 2023 (14 studies)
FIXED"Blocks" was the wrong word for what this plan does
Block periodization means concentrated blocks of a single intensity — typically high-intensity work clustered together. What this plan actually runs is traditional periodization: a gradual progression from high volume toward higher intensity and greater specificity as the race approaches. That's a real distinction, not semantics.
On the merits, block periodization has a small edge: 20 studies were screened for eligibility, but only 6 were actually pooled in the meta-analysis, which found small favourable effects for VO2max and maximal power versus traditional. The authors flagged low methodological quality across the included studies, with a mean PEDro score of 3.7 out of 10 — a small edge from a thin evidence base. Traditional periodization also remains dominant in high-performance endurance sport. Progressive volume-then-intensity is the sound default regardless — the naming is what needed fixing.
Mølmen, Øfsteng & Rønnestad, Open Access J Sports Med 2019 (20 studies)
CI was too confident that you don't need a long run near race distance
A prospective study of 556 half-marathon runners found that a longest endurance run over 21 km was associated with a faster finish time and less pace decline during the race, as was weekly volume above 32 km — and found no association between training characteristics and new injuries in that cohort. Your peak long run is 90 minutes, roughly 8.4 miles (13.5 km) — well under 21 km.
So capping there is a deliberate trade, not a free lunch: less demonstrated race-day benefit than a longer peak run would give, in exchange for a lower total training-stress ceiling heading into the race. If the build stays completely clean through week 12, extending the peak long run toward 100-105 minutes is a legitimate option.
Fokkema et al., Scand J Med Sci Sports 2020 (n=556 half-marathoners)
BThe long run sits marginally above the conventional ceiling
The widely used guideline, attributed to Daniels and Noakes, is that the long run should not exceed 25-30% of weekly volume. At peak, yours is about 9 miles of a 28-mile week — roughly 32%. Marginally over, and worth knowing that the fix is adding weekday easy volume rather than shortening the long run. This is a coaching convention with long practical standing rather than a trial result.
Daniels' Running Formula · convention, widely cited
BYour weekly volume is below the point where returns flatten
Analyses of recreational endurance performance consistently find weekly mileage and mean training pace explain most of the variance in race outcomes, and the return on additional volume, while diminishing, has not been shown to flatten out anywhere near this plan's range. Peaking at ~26 mi/week means more volume would still plausibly buy you performance — it's being held back deliberately, to keep the build sustainable through a full race cycle, not because a hard ceiling has been hit. The January strength block is where base volume can grow without a race deadline forcing the pace.
General endurance training-volume literature — direction well-supported, no single number verified for a plateau point
FIXEDThe Riegel exponent was 1.06 — corrected to 1.12
Riegel's power law needs an exponent, and 1.06 (the textbook default) is calibrated on elite/high-volume runners. It does not fit this build: Blythe & Kiraly's analysis of 164,746 runners and 1.4M performances found individual exponents average 1.12 (5th-95th percentile 1.10-1.15) for the general competitive-club population, and that a lower exponent tracks with higher ability — so 1.12 is a reasonable floor, not a midpoint, for a runner at this volume. Vickers & Vertosick (the previous citation here) fixes its own exponent at 1.07 and never validates an input shorter than 5K, so it couldn't actually license a 2-mile-trial projection in the first place.
At a 2-mile trial, this pace calculator now predicts a half about 12-14 minutes slower than the old 1.06 exponent did — every pace on this page, not just the finish-time prediction, shifts with it. Two mitigations already in the plan: treat the projection as a range, not a number, and re-test with a 10K at week 12. A 10K-to-half is a 2.1× extrapolation instead of 6.5×, and is inside the range every source here actually validated.
Blythe & Kiraly, PLoS ONE 2016 (PMID 27336162) · Riegel, American Scientist 1981
BTwo hard sessions per week with the rest easy
Directionally holds up, with a caveat worth stating plainly: in the 30-runner trial most often cited for this, both a polarised and a threshold-weighted group improved 10K time by similar amounts over ten weeks — the primary between-group comparison was not statistically significant. The polarised advantage shows up only in a post-hoc comparison of the most-adherent runners in each group. The direction (mostly-easy, not mostly-moderate) is still the safer bet and matches broader elite-training-log observations, but treat "polarised clearly wins" as more confident than the trial evidence actually is.
Muñoz et al. 2014 · Stöggl & Sperlich, Front Physiol 2014
AHills for a hilly course, and strength work to survive it
Central Park's 470-590 feet of climbing across Harlem Hill twice and Cat Hill three times makes the hill block course-specific rather than merely knee-sparing. And the strongest injury-prevention finding in the whole document applies directly here: strength training's own relative risk for sports injury is 0.315 — roughly a two-thirds reduction — outperforming stretching and proprioceptive work, with a clear dose-response relationship. Four lift days through a race build is the evidence-backed choice, not a compromise.
Lauersen et al., Br J Sports Med 2014 & 2018
CDeload every fourth week
No controlled evidence that a fixed four-week cycle beats autoregulating by feel. It's in the plan as scheduled insurance against accumulated joint load, and because it gives the testing protocol a natural home on fresh legs. Convention, honestly labelled.
Convention, not trial data
CTwo weeks of easy running after the race
The "one easy day per mile raced" heuristic has no trial behind it. What is established is that prolonged running measurably degrades the determinants of endurance performance — a study in trained marathon runners found VO2peak dropped 3.1% after 90 minutes and 7.1% after 120 minutes of running, with running economy deteriorating progressively. Recovery is clearly needed; the specific fourteen-day number is convention.
Prolonged running determinants study, 2025 · heuristic otherwise
A10+ sets per muscle per week is optimal — why you now lift four times, not twice
An umbrella review of the hypertrophy literature concluded at least ten weekly sets per muscle is optimal. A separate systematic review put the band at 12-20 sets for trained young men, while finding no significant difference between moderate and high volume for quads and biceps specifically. Your current numbers — 8 to 12 across muscles — sit inside that band. The two-session version sat below it.
Frontiers in Sports & Active Living 2022 umbrella review · Baz-Valle et al., 2022
AFour hard sets per muscle per week still grows muscle — your bad-week fallback
A narrative review established a minimum effective dose of about four working sets per muscle per week, performed close to failure, at loads corresponding to 6-15 repetitions. For strength specifically, 2-3 sets per exercise per week at 70-85% of one-rep max is sufficient. This is why dropping to two sessions during a brutal quarter isn't abandoning the plan.
Iversen et al., Sports Medicine 2021 · Androulakis-Korakakis et al.
AStopping 1-3 reps short of failure is enough
A meta-regression across 55 hypertrophy and 67 strength studies found growth improved as sets got closer to failure, but the slope flattened past about 2 reps in reserve — and proximity to failure did not help strength. An 8-week randomised trial in trained adults found similar quadriceps hypertrophy whether sets went to true failure or stopped at 1-2 RIR. Practical translation: 1-3 RIR on hypertrophy work, 3-5 on heavy strength sets, true failure rarely if ever.
Robinson et al., Sports Medicine 2024 · Refalo et al., J Sports Sci 2024
BTwice-weekly frequency per muscle — a defensible default, not a proven optimum
Frequency effects independent of total volume remain genuinely unsettled. A 2024 dose-response meta-regression across 67 studies and 2,058 participants flagged the frequency evidence as mixed. Upper and lower are both hit twice here because it distributes volume sensibly, not because 2× is established as superior.
Pelland et al., resistance training dose-response meta-regression 2024
CDeload every 8-12 weeks
Widely practised, thinly evidenced. There's no strong controlled data showing scheduled deloads outperform simply autoregulating by feel in recreational lifters. It's in the plan as cheap insurance against accumulated joint stress across an 18-week build, not because the research demands it.
Convention, not trial data
AStrength training is the single best-evidenced way to not get injured while running
A meta-analysis of randomised controlled trials found strength training's own relative risk for sports injury was 0.315 (95% CI 0.207-0.480) — roughly a two-thirds reduction, and the best single number in this program's favour, better than "outperforms stretching" understates it. A follow-up analysis found a similar relative risk (~0.34) with a clear dose-response relationship: a 10% increase in strength-training volume cut injury risk by more than four percentage points. This is the strongest single argument in the document for keeping two lower days.
Lauersen et al., Br J Sports Med 2014 · Lauersen et al., Br J Sports Med 2018
AHeavy lifting makes you faster — and running economy is a lower-body adaptation
A systematic review and meta-analysis found heavy resistance training improved running economy more than plyometric training, with a larger effect on time-trial performance as well. A separate review across 652 runners found high-load work at or above 80% of one-rep max improves economy, particularly at faster speeds. The protocols producing these effects ran 2-3 sessions per week for 8-12 weeks — which is the dose your Monday and Thursday lower sessions hit and a single weekly lower day would not.
Eihara et al., Sports Med Open 2022 · Llanos-Lagos et al., Sports Medicine 2024
BRunning interferes with leg growth more than cycling does
A large meta-analysis of 43 studies found concurrent training did not compromise hypertrophy or maximal strength overall, with interference showing up mainly in power and explosive strength — and mainly when both modalities were trained in the same session. A fibre-level follow-up found a negative effect on type I fibre growth specifically when the aerobic training was running rather than cycling. The picture isn't unanimous — at least one meta-analysis found the opposite modality pattern for HIIT specifically — so call this a lean rather than a settled result. Two consequences kept in your plan regardless: legs get their own dedicated volume rather than relying on running, and the hard session defaults to hills rather than flat intervals.
Schumann et al., Sports Med 2022 (43 studies) · Lundberg et al., Sports Med 2022
ASingle-run spikes predict injury; weekly totals mostly don't
See Corrections above. The operative number is 110% of your longest run in the past 30 days. This is the one hard ceiling in the running plan.
Frandsen, Nielsen et al., Br J Sports Med 2025 (n=5,205, 588,000 sessions)
BMostly-easy intensity distribution beats mostly-moderate
A randomised trial of 30 recreational runners over 10 weeks compared a polarised distribution (roughly 77/3/20) against a threshold-weighted one — both improved 10K time by a similar amount (the between-group difference was not significant; see above). A separate multi-sport trial (runners, cyclists, triathletes and skiers) found a polarised group produced the largest gains in VO2peak and time-to-exhaustion — notably, at the highest total training volume of the four groups it compared, not a lower one. No improvement in running economy specifically was found in any group in that trial.
Muñoz et al. 2014 · Stöggl & Sperlich 2014
CHill repeats as the default hard session
The reasoning is sound but assembled rather than tested: uphill running reduces impact loading relative to flat running, running interferes with strength adaptation more than cycling does, and downhill running produces the highest eccentric knee loads. No trial has compared hill repeats against flat intervals for someone in your specific situation. It's the option that stacks the fewest known risks, not a validated prescription.
Inference from impact-loading and interference literature
AFull-range lifting improves flexibility about as much as stretching
A meta-analysis of 11 randomised controlled trials with 452 participants found no significant difference between strength training and stretching for range of motion, across hip, knee, shoulder, elbow, trunk and cervical spine, with sub-group analyses by active versus passive ROM showing the same. A 2024 controlled trial matched training time and stretch intensity between groups: both improved sit-and-reach equally, and only the lifting group also gained strength. This is why your RDLs and squats are counted as mobility work in this plan.
Afonso et al., Healthcare 2021 (11 RCTs, n=452) · Rosenfeldt et al., BMC Sports Sci Med Rehabil 2024
BStatic stretching after training, dynamic before
Pre-exercise static stretching produces a temporary reduction in force output, but the actual dose-response is more forgiving than the old caution here implied: a multilevel meta-analysis (83 studies, 2,000+ participants) found bouts under 60 seconds sit in the trivial-effect range, and found no evidence for a blanket ban on stretching in warm-ups. The pre-squat calf and hamstring prep here runs 45-second bouts — safely inside that window, not an exception to the rule.
Warneke & Lohmann, J Sport Health Sci 2024