When you hit your 40s, it can feel as if all of the weight loss rules have suddenly been thrown out the window. Thanks to shrinking muscle mass and a slowed metabolism, what kept you in your skinny jeans during your 20s and 30s might stop working by your 40s. That means even your walking routine will need to change, says personal trainer Michele Stanten. You can't just lace up your shoes, hit the pavement at a fast clip and expect results. 

"The same walks that helped you control your weight and stay firm in your 20s and 30s just aren't going to cut it in your 40s," she says.

Maximise your fat and kilojoule burn with these breakthrough walking workouts from Stanten.

30-20-10 Intervals

The faster you go, the more kilojoule you burn. That may seem like common sense, but what you may not know is that kilojoule burn increases exponentially, not linearly, when you crank up your pace. 

Speeding up from 4 kph (15-minute-per-kilometre pace) to 5 kph (12-minute-per-kilometre pace) nets you an extra 150kJ (36cal) an hour. But a 1 kph increase at faster speeds results in bigger jumps in kilojoule burn. Going from 5 to 6 kph (12- to 10-minute-per-kilometre pace) blasts an extra 238kJ (57cal) an hour. 

And you get the greatest kilojoule bumps when you rev up above 6.5 kph (9-minute-per-kilometre pace). Going from 6.5 to 7 kph (8.5-minute-per-kilometre pace) incinerates nearly an extra 627kJ (150cal) an hour. 

There are also more health benefits to be gained by speeding up: lower cholesterol, lower blood pressure, better blood sugar control and reduced risk of several diseases. With all of those healthy benefits, it's no surprise then that faster walkers also tend to live longer than strollers, according to research. 

Luckily, you don't have to push the pace for a full 30 minutes to get results. You can do shorter interval workouts instead. Interval training involves mixing faster speeds or intensities with slower speeds or intensities to challenge your muscles and lungs. 

Try this superfast kJ-incinerating interval workout to max out your metabolism.

•    Warm up for 3 minutes
•    Walk briskly for 30 seconds (aiming for an intensity of a 6 on a 1-to-10 scale)
•    Walk even faster for 20 seconds (aim for an intensity of an 8)
•    Kill it by going as fast as you can for 10 seconds 
•    Perform 3 to 4 total 30-20-10 cycles, recovering by walking slowly for 1 minute between each cycle

Walk and Tone Workouts

Starting around age 25, most people lose about 2 to 5 kilos of muscle each decade. Through strength training, however, you can build and maintain fat-burning muscle that will power up your walks and burn more kilojoules - even when you're not on your feet. 

You don't need to do long strength-training workouts at the gym. Instead, try this "toning walk" three times a week. 

3 minutes: Warm up 

4 minutes: Walk briskly (aiming for an intensity of a 6 or 7 on a 1-to-10 scale) 

Walking lunges: Take a giant step forward with your right foot. Bend your knees and lower your body straight down toward the ground. Your right thigh should be parallel or almost parallel to the ground. Keep your right knee over your right ankle. Your back (left) knee should be pointing toward the ground. Your left heel will come off of the ground. Press into both feet to stand back up, bringing your left foot forward to meet your right foot. Now step forward with your left foot. Do 20 reps, alternating which foot "walks" forward with each rep.

4 minutes: Walk briskly (aiming for an intensity of a 6 or 7 on a 1-to-10 scale)

Elevated push-ups: Place your hands shoulder-width apart on a bench, wall, railing, log, picnic table, piece of playground equipment, or anything else you can find. Walk your feet back so your body forms a plank—or a straight line from your head to your ankles. Keep your head in line with your spine and don't bend at the hips. Bend your elbows at a 45-degree angle from your torso and lower your chest toward the bench. Hold for a second, and then straighten your arms, pressing back to the start position. Do 10 to 12 reps.

4 minutes: Walk briskly (aiming for an intensity of a 6 or 7 on a 1-to-10 scale)

Travelling squats: Stand tall with your feet together. Step your right foot out to the side so your feet are just wider than shoulder-width apart. Bend your hips and knees and lower your butt as if you were sitting in an imaginary chair. As you lower, keep your knees behind your toes, your head up, and chest lifted as you lower. Lower until your butt is just above knee height. Hold for a second, and then press into your feet to stand up, bringing your left foot in to meet your right. Repeat stepping to the right with your right foot. Do 10 reps moving to the right, and then 10 reps stepping to the left.

4 minutes: Walk briskly (aiming for an intensity of a 6 or 7 on a 1-to-10 scale)  

Plank walks: Stand tall with your feet together. Bend your knees and squat all the way down, placing your hands on the floor right outside your feet. Keep your feet stationary and walk your hands forward until your body forms a plank (think: the top of a push-up). Your body should form a straight line from your head to your heels, balancing on the palms of your hands and your toes and balls of your feet.

Then, keeping your hands stationary, walk your feet toward your hands. Repeat walking your hands out, and then your feet to meet them. Do 10 to 12 reps.

4 minutes: Walk briskly (aiming for an intensity of a 6 or 7 on a 1-to-10 scale)

2 minutes: Cool down

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