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The 4×4 Workout: Science and Practice of a Revolutionary Protocol

If you’ve ever looked for a training method that can improve your endurance and speed without spending hours running, the 4×4 method might be exactly what you need. It’s not just another high-intensity workout — it’s a protocol developed by researchers at the Norwegian University of Science and Technology (NTNU), designed to maximize oxygen uptake (VO₂ max) and boost cardiovascular health.

At first, I was skeptical: how could just 16 minutes of intense effort, split into four intervals, lead to significant benefits? But once I incorporated it into my routine, the results came quickly — greater endurance, less fatigue on long runs, and steady improvement in race times.

How the 4×4 Method Works

The original protocol is simple but effective, based on a precise alternation between intense effort and active recovery:

  1. Warm-up – 10 minutes of light running, gradually increasing intensity.
  2. Intervals – 4 minutes of running at high intensity, targeting 85–95% of your maximum heart rate. The goal is to reach that zone only in the last 2–3 minutes of each interval.
  3. Active recovery – 3 minutes of easy jogging or brisk walking, keeping the heart rate around 60–70% of the max.
  4. Repeat – Complete 4 cycles in total.
  5. Cool down – 5–10 minutes of light running to gradually return to a resting state.

The whole session takes about 45 minutes — a manageable time investment for real, measurable progress.

Common Mistakes to Avoid

I made a few mistakes at first that slowed my progress. Here are the main ones — and how to avoid them:

  • Not tracking heart rate: Using a heart rate monitor is crucial to ensure you’re training in the correct zones. (A chest strap is best, but a watch works fine too.)
  • Starting too hard: The first minute of each interval should be controlled; aim to hit your target zone only in the final minutes.
  • Resting passively: Stopping completely between intervals reduces the workout’s benefits. Active recovery helps clear lactate and prepares you for the next repetition.
  • Keeping the same speed: As your fitness improves, you’ll need to adjust your pace to maintain the right intensity.

How to Fit the 4×4 Into Your Weekly Training

To get the most from the 4×4 method, balance is key. Here’s how I schedule it in my weekly plan:

  • Tuesday: 4×4 workout
  • Wednesday: Easy recovery run
  • Friday: 4×4 workout
  • Sunday: Long run at moderate pace

This setup allows you to balance intensity with recovery, avoid overtraining, and reduce injury risk.

Benefits Beyond Performance

After several months using the 4×4 method, I noticed improvements beyond race results. My energy efficiency increased, recovery between sessions became faster, and I developed greater mental resilience to handle intense efforts. Plus, the solid scientific foundation behind the protocol makes it a reliable and sustainable choice for anyone seeking measurable progress.

If you’re looking for an effective, time-efficient workout to fit into your schedule without endless mileage, I highly recommend giving it a try.

And you? Have you ever tested the 4×4 method? What were your impressions?