This is the last chapter of our story. We started with the two evil villains: low-intensity cardio and hypertrophy. For so long now they have infiltrated and attacked unknowing trainers and trainees, spreading their dastardly mix of boredom and fattiness.

But fear not, the story has taken a turn for the better; a hero emerged in the name of strength circuits with a big "SC" emblazoned on his chest. Finally, some common sense in effective, smart and bang-for-your-buck-style training has arrived.

But wait, I have more good news; another hero lurks just around the corner in the name of high-intensity interval training, or HIIT to his mates. HIIT, like Robin was to Batman, is the perfect side-kick to strength circuits. Sure strength circuits is a star performer in its own right, but together with HIIT, fighting the good fight, they make an irresistible team.

Here's what HIIT can look like. I often do this session in my favourite local outdoor training spot, Centennial Park in Sydney's east.

1. We run for five minutes as a warm-up and end up at a 40m medium-grade hill.
2. We then sprint fast up the hill 10 times (each rep takes 14-35 seconds depending on the client).
3. Between each rep we walk down the hill; we generally start the next rep 90 seconds after we began the previous.
4. We then have a drink and jog for five minutes to a set of stairs.
5. We do five sets of doubles (two stairs cleared per stride) then five sets of singles (touching every step).
6. On a particular set of stairs we train on, there are three distinct flights. So we do one flight of two-foot jumps, one flight of doubles and one flight of singles, all consecutive and on the same trip from top to bottom. We do five sets of this.
7. We then (yes, there's more) run about 400m to a smaller (10-15m in length) and slightly steeper hill.
8. We do five fast sprints up the hill with a walk down recovery between each sprint.
9. We then finish things off with three sets of two-foot jumps up the hill.
10. We cool down with a 5-10-minute stretch

Yes, I hear you, it's a hell of a session. But in saying that, I have clients in their sixties doing this. Sure, they're not your average 60-year-olds but it just depends on finding what constitutes "high intensity" for you.

A second factor with high-intensity training is getting the rest intervals right. If they are too long, you won't get an effective work-out and your session volume will be low. If your rest intervals are too short, you'll burn out too early in the session and one of two things will happen. You'll either fade badly and lose all intensity for the rest of your session, or you'll make friends with a tree and revisit breakfast. Neither is ideal, needless to say.

Have a crack at a work-out like this tomorrow. You may have to make a few alterations, taking into consideration your local park or outdoor training spot, but with a bit of creativity it's possible. Get to it!

HIIT rating

• Fitness: A+
• Fat loss: A-
• Strength: B-
• Muscle definition: B-