Estimated read time: 6.15 minutes (about as long as it takes to convince yourself you'll "definitely lift tomorrow" after your morning run 🤔)

Hey Performance Nerds! Jonah here. 🤓

A 43-study research review found that combining running and lifting doesn't reduce your strength or muscle size.

Many runners skip the gym because they think they need a separate day. They don't.

Same-day training works. Your squats and your schedule both survive.

You just need to sequence it right.

Here's what you'll learn today:

(Augie's training schedule is 100% nap-based. Somehow his explosiveness off the couch remains elite.)

I've been getting the same question for months: "Do you have a half marathon plan?"

So I built one. Three, actually. Beginner, Experienced, and Advanced, developed with PhDs and coaches, delivered through a quick quiz that matches you with the right fit.

I was going to charge for it. But you've supported this newsletter from the start, and I wanted to say thank you the best way I know how: with something useful.

Reply to this email and tell me you want it. I'll send you the quiz.

Now, about fitting strength training into that plan...

The gel I race with (and why):

BETA FUE: delivers 80g of carbs per serving through a 1:0.8 maltodextrin-to-fructose ratio.

That ratio is why I've never had a GI issue with it in 3 years of racing. Fast absorption, no gut bombs. I don't earn a commission on this. I negotiated 15% off for you because I believe in the science behind it.

Marathon Science subscribers get 15% off one-time purchases with code JONAH26. Live now through May 31.

The running power meter trusted by serious athletes — is now an official performance sponsor of Marathon Science, delivering real-time pacing precision so you can train smarter and race faster.

💡 See this week’s full Stryd training tip at the end of this newsletter.Stryd

"Cardio kills gains." You've heard it. Maybe you believe it.

Schumann et al. (2022) reviewed 43 studies on runners who also lifted. The result?

Combining running and lifting did NOT reduce max strength or muscle size.

For most recreational runners, this interference is likely small. The effect only becomes meaningful at very high volumes, where cumulative fatigue degrades session quality.

More running sessions relative to lifting sessions, particularly for explosive strength (Jones 2013).

If your weekly volume is moderate, your strength gains are protected.

But explosive strength told a different story. Jump height and sprint power dropped when athletes trained both in the same session.

Here's the key distinction:

As a runner doing 5-6 sessions per week, your squat is safe. Your plyometrics? That depends on timing.

For most runners, heavy lifting is protected. Plyometrics and explosive work take the hit.

How long between running and lifting? Everyone asks this.

Robineau et al. (2016) tested three gaps in 58 team-sport athletes over 7 weeks. Same session, 6 hours apart, and 24 hours apart. The recovery principle aligns with Schumann's broader meta-analysis, which included runner populations.

24 hours was best for both strength and aerobic gains. Six hours was better than same-session but not optimal.

The bigger finding from Schumann et al. (2022): a 3+ hour gap removed the statistically significant interference on explosive strength.

The practical sweet spot: 6+ hours. Morning run, evening gym. That's enough for most runners.

What if you only have one training window?

Murlasits et al. (2018) looked at session order. Lifting first produced 3.96 kg higher leg strength gains compared to running first.

VO2 max? Unaffected by order.

Here's the nuance: that finding applies when strength is your primary goal.

If running is your priority, run first. Protect the quality of the run.

Then lift afterward, even in the same window. Your strength gains won't disappear.

Lift first only if maximizing strength is the main goal. For most runners, run first.

This is the most common scheduling mistake I see.

Don't lift right before a hard running session.

Going into intervals or a tempo run with fatigued legs is the worst-case scenario. You compromise the session that actually drives your fitness forward.

The interference effect is strongest at 0 hours of separation. Stacking a gym session right before high-intensity running means you compromise the quality of both sessions.

If you have to choose between lifting before intervals and skipping the gym, skip the gym.

Protect the hard run. Move the lift to later in the day, or to a different day.

I keep at least 48 hours between a lower-body lift and my next hard run. That way any fatigue from the gym doesn't bleed into the session that matters most.

But if your only window is right after a hard run, take it.

A fatigued gym session still builds capacity. Some stimulus beats no stimulus.

The research describes ideal conditions. Your real week rarely looks ideal. A compromised lift still moves the needle more than a skipped one.

And your easy run the morning after leg day? It will feel heavy. That's muscular fatigue, not fitness loss.

Run by effort, not pace. Your aerobic engine is fine. Your legs are just sore.

Not every training day needs the same gym session. Here are two approaches that both work.

Stack your hard running and heavy lifting on the same day.

Run in the morning, lift in the evening with a 6+ hour gap.

This keeps your easy days truly easy and your recovery days truly for recovery.

This is what Blagrove, a Loughborough researcher who's spent years studying how distance runners should strength train, advocates. It's also what I do.

I run hard in the morning, then lift later that day. Plenty of recovery before my next hard session, and my easy days stay easy.

My actual week during a standard training block:

Hard days stay hard. Easy days stay easy. Two lifts per week, both after the sessions that matter most.

Keep plyometrics and explosive work on a different day from hard running. These need fresh legs and suffer most from prior fatigue.

Heavy resistance is more flexible. It can go on hard days or easy days.

This is the key nuance from Blagrove's work with distance runners: explosive work is what's actually vulnerable. Heavy lifts tolerate fatigue well.

Key rules from both paths:

Bottom line: Same-day training works. Stop waiting for the perfect day and start sequencing the one you have.

Welcome to the prove you’re a nerd section. Each week, I ask a question about a common running science myth.

Answer correctly, and you’ll be entered into a weekly raffle to win a package of Jonah’s favorite supplements.

“The wall” feels mysterious when it hits. Legs turn to concrete, pace collapses, and every step suddenly costs more than it should.

The correct answer?

B. They maintain blood glucose, reducing strain on liver glycogen and sustaining fuel delivery 🍯 ✅

During a marathon, your muscles burn through glycogen quickly. Without fueling, your liver has to keep releasing stored glucose to keep blood sugar stable. Eventually those liver stores run low.

Carb intake during the race keeps blood glucose steady, which reduces the burden on liver glycogen and keeps fuel flowing to the brain and working muscles. That’s the real mechanism behind delaying “the wall.”

It is less about refilling muscle glycogen mid-race. It is about keeping the bloodstream supplied with usable carbs.

Here’s how the votes shook out:

⬜️ A. They prevent a dangerous drop in blood sugar that would otherwise happen in most runners 🩸 – 3
🟩 B. They maintain blood glucose, reducing strain on liver glycogen and sustaining fuel delivery 🍯 – 213 ✅
🟨 C. They directly refill depleted muscle glycogen stores while you run ⛽ – 59
⬜️ D. They stop muscle fatigue by replacing sodium lost in sweat 🧂 – 3

A surprising number of people chose muscle glycogen refilling.

It sounds logical, but muscles don’t rapidly refill glycogen while you’re racing. Carbs you ingest mostly enter the bloodstream first and are oxidized directly by working muscles.

Bottom line?

Gels don’t magically refill empty muscles. They keep blood glucose steady so your muscles and brain never run out of fuel in the first place.

I squatted heavy on Wednesday. Thursday's easy run felt sluggish. Pace down, legs heavy. But I wanted to know: how much did lifting actually change my mechanics?

That's where Form Power comes in. Form Power captures energy you spend bouncing up and down instead of moving forward. After a hard leg session, my Form Power Ratio climbs. Sore quads and stiff calves mean longer ground contact, lower leg spring stiffness, and a bouncier stride. Stryd quantifies exactly that.

On easy days, I don't stress about it. I wanted the stimulus. But I track Form Power Ratio in PowerCenter because I want it back to baseline before my next hard session.

Why it matters:

Next leg day, check your Form Power Ratio on the run after. That's your chassis talking.

👉 Try it on your next run