James Anderson of outdoor-training group Phat Fit has been a personal trainer for 15 years. His approach to fitness is all about flexibility and simplicity.

“I've watched far too many people try to shove themselves into a box that someone else has designed, thinking that it's the only way to exercise,” says Anderson, who's based in Sydney. “If it's not something that makes you stronger, healthier and happier, then what's the point? People make it too hard for themselves. Complicated programs for people with already complicated lives always lead to failure.”

Anderson put the below session together for when his clients are short on time and need a high-intensity workout. It is suitable for almost anyone and can be modified based on fitness level. Any soft, dry sand will work. (For those in Sydney, Anderson's pick for location is between the ramps at North Bondi.)

Part one: pyramid intervals
Begin by marking a point approximately 100 metres away on the beach. Have a timer handy.

Hit start on the timer. Run up to the marker and back as fast as you can. Hit stop, and rest for the same amount of time it took to complete the run; ie if set one takes two minutes, rest for two minutes.

Repeat this twice more for set two, increasing until you’ve run four laps, then work your way back down to one.

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Set 1: 1 lap
Set 2: 2 laps
Set 3: 3 laps
Set 4: 4 laps
Set 5: 3 laps
Set 6: 2 laps
Set 7: 1 lap

If you want to push yourself harder, halve your rest time. If you’re struggling, double your rest time, but work toward shorter rests as your fitness improves.

Technique-wise, try to run with a slight lean forward, keeping your arms close to your sides. Aim to strike the sand with your forefoot and drive hard out of the sand each time.

Most importantly, make sure you run fast enough to earn the rest period at the end of each set.

This workout is effective because it allows you to train at a higher intensity than normal. “The rest periods enable you to recover enough to be able to push your thresholds again; the end result is an increase in fitness and health,” says Anderson. The softness of the sand also makes it harder to generate force when compared with running, so you'll be feeling the burn the next day.

Part two: seven-minute soft-sand AMRAP
AMRAP stands for “as many rounds as possible”, so try to complete as many circuits of the below exercises as you can in seven minutes. Anderson says it’s important not to sacrifice good form for numbers, though, so while you should be working as hard and as fast as possible, prioritise technique.

15 air squats
10 push-ups
5 burpees

For the air squats, Anderson says keep your arms forward, knees out, chest up, and your stomach tight. For the push-up, your elbows should be pointed slightly backwards and your stomach tight with a straight spine. Lead with your chest, rather than your forehead, and don’t allow your hips to sag downwards.

“There are so many variations to a burpee so find one that works for you. I prefer using more of my legs rather than my back by first squatting down and placing my hands between my feet, then jumping my feet back and lowering my body to the ground at the same time,” says Anderson.

“Then I press back up, jump my feet outside my hands (rather than behind my hands as it allows me to squat out of this position in not bend excessively), then I stand and do a slight jump off the ground with a straight spine and press my hands above the head.”

Rest if you need to, but with this workout, minimise downtime. “Try to push yourself outside your comfort zone with this one,” says Anderson. “Although you might want more rest, we both know you've probably got a couple more reps in the tank before you really do need a rest.”

And finally, says Anderson, "Now go for a dip."

James Anderson runs Phat Fit.

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