Today I tried a proper Jakob Ingebrigtsen double‑threshold day as part of my build‑up towards running sub 18 for 5K. I didn’t hit the full elite volume, but I got a real taste of how this style of training works — and why it’s so effective.

In the morning, I managed 7×6 minutes at my controlled threshold pace. Smooth, steady, no ego. Then in the evening, I went back out for 4×5 minutes, again keeping everything under control. It wasn’t perfect, but it was enough to understand exactly why Jakob trains like this.

So why does he do double‑threshold?
Because it lets him stack a huge amount of quality aerobic work without blowing up his body. Threshold sits right under the point where lactate spikes — the sweet spot where you can build endurance, improve lactate clearance, and recover fast enough to do it again tomorrow. Jakob isn’t chasing pace; he’s chasing physiology.

The benefits are massive:

• Aerobic engine growth — the foundation of all fast 5Ks.
• Better lactate clearance — your body gets efficient at handling fatigue.
• High volume at quality — pros can hit 20–30 minutes twice a day.
• Lower injury risk — hard work without destructive spikes.


And this is where pros differ from us. They’re not faster because they train harder — they’re faster because they can handle more controlled work. They recover quicker, they monitor lactate, and they keep their easy days truly easy. Most amateurs do the opposite.

If you want to estimate your own threshold without a lactate meter, use:

• Heart rate: 88–92% of max.
• Pace: roughly your 1‑hour race pace.
• Feel: controlled discomfort, but form stays clean.
• Talk test: short sentences possible, but not comfortable.


This session is another step in my journey to break 18 minutes for 5K. It’s not glamorous, it’s not flashy — but this is the kind of consistent, controlled work that actually moves the needle. More big sessions coming soon.

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