Jakob Ingebrigtsen does this workout TWICE a day

The Norwegian Method.
Pioneered by Marius Bakken and made famous by Jakob, Henrik & Filip Ingebrigtsen.

8 × 1000m at threshold pace (lactate 2.5–3.0 mmol/L). Morning session.
Eat. Nap. Then do it again in the afternoon.

The trick: lactate UNDER three means you can recover and stack a second session.
Most amateurs push lactate to 5–6 on every workout — and never recover enough to go again.

Volume + sub-threshold intensity = the engine that makes Olympic champions at 20.

Don't try this without a coach and a lactate meter. But understand the principle:
go slower more often, hit the threshold without crossing it, and stack the work.

Follow @runnersvibe for the breakdown of how a recreational marathoner can apply the principle (less volume, same logic) ↓