A Study: Is SMIT The Superior Training Method for Hybrid Athletes?

If there’s one number that consistently separates top athletes from the rest, it’s VO₂max. In football, it is correlated with time spent with the ball and a lower risk of injury; in motorsports, greater aerobic capacity improves decision-making under fatigue.

In almost every sport, the athlete with the highest VO₂max is usually the fittest, most durable, and hardest to drop when it counts. 

But how do you train VO₂max without becoming slow?

Most people have heard of the classic 4x4-minute intervals. Four minutes hard, four minutes easy—also called the “Norwegian intervals.” It definitely works. But is it the best when you want to excel in all areas of performance?

If you’ve done these, you know how beaten up you feel after the last interval. An often overlooked angle is RPE (rate of perceived exertion)—how the session feels. Sure, everyone swears they can push hard all day, but there are days you’re fatigued, under-recovered, and the calendar still says: time to push 4x4. Makes you think—is there another option? Well, there just might be.

The Study: HIT vs. SMIT vs. Steady State

A 2013 study compared three training methods over six weeks in recreational athletes. Before starting the training program, they were measured using three performance tests:

• 3000m time trial (VO₂max)

• 40m sprint (power & speed)

• 6x40m sprint (repeated sprint ability)

In other words: a great testing setup for hybrid athletes who want to become genuinely athletic—both durable and fast.

Then the test subjects were assigned one of the following training protocols:

• HIT (High-Intensity Intervals): 4–6 x 4 minutes at 100% of 3000m pace (1:1 work:rest)

• SMIT (Supramaximal Intervals): 7–12 x 30 seconds at 130% of 3000m pace (1:5 work:rest)

• CONT (Continuous Running): 30 minutes steady at 75% of 3000m pace

All groups trained 3x/week. In HIT, volume increased by 2 sets every 2 weeks; in SMIT, volume increased by 1 set each week.

What Happened?

All groups improved their 3000m time—but SMIT outperformed steady-state running. HIT showed slightly better improvement in 3k time, but the difference wasn't statistically significant.

When it comes to sprinting, only SMIT improved 40m sprint times significantly.

Repeated sprint performance also improved the most with SMIT.

HIT improved endurance but did little for speed. Unsurprisingly, steady-state running was the weakest across all performance areas.

And here’s the kicker: SMIT used the lowest training volume—but delivered the broadest performance improvements. That makes it not only time-efficient but also extremely effective from a return-on-volume perspective. For hybrid athletes, that matters—a lot—because you’re juggling multiple training qualities to stay well-rounded.

Time improvement in 40m sprint. Note that only in SMIT the difference is statistically significant.

Why This Matters for Hybrid Athletes

Following a high-quality hybrid training program means becoming both fast and enduring. If your intervals build VO₂max but compromise your power or repeatability, they’re not really helping you become a better hybrid athlete.

This study makes it clear: SMIT delivers both endurance and speed gains, making it an ideal tool for anyone trying to stay explosive while building their engine.

Want VO₂max? You have options.Want VO₂max plus speed and resilience? Consider implementing SMIT into your hybrid training program.

Takeaway:4x4s work best for VO₂max. Steady state is fine and needed for other adaptations—but does little for VO₂max or speed. SMIT wins on all fronts. For hybrid athletes, it's the most bang for your buck.

Source: Cicioni-Kolsky, D., Lorenzen, C., Williams, M.D., & Kemp, J.G. (2013). Endurance and sprint benefits of high-intensity and supramaximal interval training. European Journal of Sport Science, 13(3), 304–311. https://doi.org/10.1080/17461391.2011.606844