Whether you're an advanced athlete or just starting out on a fitness regime, Davide Butson-Fiori says 25 seconds is just the right duration for each high-intensity strength or resistance interval of a circuit training programme.
'Everyone can handle it,' says the founder of Circuit25, a group fitness training company. 'The advanced might do 20 repetitions, while the beginner might do five. But everyone gets a workout, and no one gets left behind.'
The following circuit is based on the C25 Minute Travel Workout created by Butson-Fiori for travellers to stay fit on the road.
All you need is a resistance band and some space; a park or even your hotel room will do.
In just 25 minutes, you'll work all the major muscles in your body through a series of strength and resistance exercises alternated with cardio.
0 minutes (workout time elapsed)
Warm up: Begin by warming up with five minutes of jogging or skipping to get blood circulating to the muscles.
Cardio: (50 seconds with 10-second rest) butt kicks - bring heels to butt, one at a time, focusing on quick kicks, not racing forward.
Strength: (two sets of 25 seconds with five-second rest between sets) Shoulder raise  - Place band under feet and grab top of band with hands close together. Keeping your arms straight, lift parallel to the ground, then return slowly to the start position.
Cardio: step-ups - step up on an elevated platform with left leg, drive right knee up towards chest, then bring right leg back on ground. Alternate stepping up with right leg.
Strength: standing row  - Place band around a fixed object, such as a tree, at about waist level. Keeping your back straight, pull elbows straight back to your side, then slowly extend forward.
Cardio: mountain climbers - in push-up position, do high-knee jogging on the spot.
Strength: side plank with leg raise  - From push-up position, shift weight to the left, balancing on just the left arm and leg. Hold. Keep core tight.
Strength: bicep squat  - Place band under feet, shoulder width apart. Lower into squat position while doing a biceps curl. Keep chest up and back straight. Stand up, lowering arms.
Strength: lunge with a twist  - Lunge forward with left leg, ensuring the left knee is directly over the ankle. Twist the body to the right, then return to standing position.
Alternate with right leg (twist to left).
Cardio: mountain climbers
Strength: ski jump  - Get into squat position, as though sitting on a chair. Swing arms forward as you jump up and ahead. Land with knees bent to absorb shock. Repeat.
Cardio: butt kicks
Strength: tricep reach  - Step on band and grab ends with both hands behind your back. Extend hands above head, then slowly return down towards your back.
Cool down: Five minutes of jogging and stretching.