Do the Britney sofa workout

If you intend to spend Sunday slouched in front of the television feeling ever more guilty that you are not out pounding the marathon streets, then follow Britney Spears's self-help steps. Who needs a gym when you've got a sunlounger - or a sofa. Britney interrupted some serious sun-worshipping over the weekend to execute a series of moves designed to flatten her stomach and tighten her thigh muscles, and experts say that she has the right idea.

"It is possible to do a reasonable amount of exercise on a sunlounger or on your sofa at home," says Dean Hodgkin, director of fitness at Ragdale Hall Health Hydro, in Leicestershire, who has devised a "chairobics work-out" especially for life's reluctant exercisers. "Obviously," he says, "it will not replace regular walking, swimming or cycling as it won't get you aerobically fit, but every exercise you do will count towards overall improvements in fitness."

So, to help you get fit Britney-style while watching the marathon, we have devised a work-out that can be performed any time on a sofa or sunlounger. John Brewer, director of the sports-injury-and human-performance centre at Lilleshall National Sports Centre, in Shropshire, advises anyone embarking on the exercises to warm up first by walking for a few minutes.

And, if you can summon up the effort, he says you should try increasing your cardiovascular activity by power-walking (perhaps to get a cocktail on the beach) or stepping up the stairs several times during a commercial break at home.

Stomach blaster

Lie on your back on the sofa with knees bent at a 90-degree angle and with your hands on your stomach. Tilt your pelvis to press your lower back into the sofa's surface and suck in your abdomen. Lift your right leg up with the knee bent, keeping your back and shoulders on the sofa. Then, extend your left arm across your body until it reaches the right knee. Push that hand against the knee, resisting the pressure. Hold for six seconds and release. Repeat three times and then change sides.

This exercise helps create a girdle of muscle to support the spine as well as strengthen the stomach muscles.

Squats

This is an excellent exercise for working the muscles in the lower body, including those in the thighs and buttocks. Raise yourself off the sofa and stand with feet hip-width apart. Make sure your back is straight and your abdominal muscles tucked in, and place your hands on the back of the sofa to use it as support.

Slowly bend your knees to an angle of approximately 90 degrees, leaning forward with your upper body (so that your bottom sticks out). Keep your feet flat on the floor at all times and don't lean too far forward. With your back straight, squeeze your buttock muscles tightly, then slowly return to the start position. Repeat 15 times.

Cobra

Lie face down on the sofa with your palms flat, parallel with your shoulders. Push up from your hands, tilting your head back slightly, facing forward as you rise. Keep your pubic bone pressed into the surface of the sofa and keep your buttocks relaxed. Slowly arch your spine backward, locking but not straightening your elbows, until you are looking at the ceiling. Hold the position for a count of three and then slowly descend. Repeat six times. The Cobra is a classic yoga movement that not only improves flexibility in the spine but increases core strength and works muscles in the upper and lower back.

Crunches

The abdominal crunch exercise is the best way to tone the muscles that shape your midriff. This is a modified version that you can do without moving far from your sofa or lounger. Lie on your back with knees bent and your legs resting on the seat part of the sofa or lounger, pushing your bottom as close to it as is comfortable. Then, either place your hands lightly by your ears or cross your arms over your chest. Keeping your lower back on the floor, tense your abdominal muscles and lift your shoulders upwards.

The movement should be a subtle one and your back should remain on the floor. Hold for three seconds before slowly lowering back down again. Repeat 15 times.

Heel beats

Lie on your stomach and use the backs of your hands to create a pillow for your forehead. Lift your legs off the sofa to buttock level (ie, four or five inches) and keep them about shoulderwidth apart. Click your heels together quickly, then return to shoulder-width apart, keeping your toes turned outward. Repeat this in-out motion as many times as you can while counting out loud to 20. Return your legs to the sofa and repeat for another count of 20. This move works the inner-thigh and lower-back muscles as well as improving strength and flexibility in the hips.