Summarize this article in one sentence.
The biggest loser has made available a quick, five-minute workout that you can use whenever you have some spare time.  You won't need any equipment as the exercises only require your bodyweight to be effective. If you find yourself pressed for time or simply have a few minutes to spare try using this quick and effective workout to help you stay in shape.  Do each motion for 20 seconds. Rest after each motion for 10 seconds. Try to do as many repetitions as you can during the 20 second active phase. Squat jumps are an exercise that can target your legs and engage your cardiovascular system.  The movement will use a large range of motion to work your quadriceps, glutes and raise your heart rate.  Try to use proper form as you work to get in as many squat jumps as possible.  Start by standing straight with your feet at shoulder width. Squat down until your knees are bent at ninety degrees.  Keep your back straight and your weight in your heels. Launch up from this position, jumping into the air. Land gently and return to the starting position before repeating the movement. Mountain climbers will raise your heart rate, exercise your cardiovascular system, and strengthen your arms, upper body, legs and core.  It's a great total body motion that can allow you to get a good workout in a short amount of time.  Start the motion in an upright plank position.  You should be on your hands and toes, suspending your core in the air. Bring your right knee in and up towards your chest and return it to the starting position. Raise your left knee in and up towards your chest before bringing it back behind you. Repeat this motion alternating between right and left knees for the full 20 seconds. Hip raises will target your core muscles and allow you to fully engage them as you lift your legs up into the air.  The motion itself is simple but it still offers a challenge and makes a great addition to this quick workout.  Lay down on your back with your arms out to the sides and legs straight up in the air. Raise your legs and hips up as high as you can using your core. Lower you legs and hips back down before repeating the motion. High knees will bring up your heart rate and allow you build strength in your core and upper legs.  Try to bring your knees up and down as quickly as you can during the motion while maintaining good form.  Start by standing up straight. Quickly bring your right knee up to hip level and bring it back down. Do the same for your left knee, raising it up and bringing your leg back down. Repeat this cycle, raising your right then left knees as quickly as you can for your 20 second set. Windshield wipers involve a simple motion that can be quite a challenge for your core muscle group.  This motion can also help strengthen the legs to a degree.  If you find the standard motion too difficult, try bending your knees inwards at a ninety degree angle or less.  Lay down on your back with your legs straight up in the air.  Your arms should be out to the sides as support. Slowly lower your legs down to the left side of your body before raising them back up to the center. Repeat the motion, lowering your legs to the right side of your body and returning them to the center position. Continue this motion until the 20 seconds have passed. Yoga push ups are a more dynamic motion than regular push ups and will engage the entire body.  You will be able to build both strength and flexibility during this movement.  Focus on maintaining the proper form using the following motions:  Start in a push up position, resting on your hands, toes, and keeping your arms straight.  However, for this motion you will start with your butt slightly raised up. Lower yourself down using your arms until your elbows are bent at ninety degrees. Raise your self back up, head first, keeping your back and butt low. Extend your head up and lock out your arms to enter a cobra stretch. Bring your body and head back down before rising once again to the starting position. Ski jumps are a complex movement that engages the arms, upper body, core and legs.  Working to do as many ski jumps as you can during your 20 second set will help target your cardiovascular system as well.  Start in a push up position with your arms straight, resting on your hands and toes. Keep your hands where they are and jump your feet out towards your left arm. Return to the center position and jump your feet out towards your right arm. Bring your legs back to the center position and repeat the whole cycle again. The reverse bear crawl will help build strength and agility, utilizing many different muscle groups at once.  The focus will be on your shoulders, triceps, core and legs.  Try to move as far as you can using this motion to get the most from it.  Start by resting on your hands and feet, with arms straight and chest facing upwards. Move your left arm backwards and your right leg inwards. Walk backwards by bringing your right arm backwards and your left leg in. Keep this walking motion going for your full 20 seconds. The scissor motion will fully engage your core and legs to a great degree.  Although the motion itself is simple it can be a challenging addition to your workout.  Try to do as many repetitions of the motion as you can during your 20 second time limit to ensure that your core is fully engaged.  Lay flat on your back with your arms at your side, resting on the ground. Bring your legs up into the air and keep them apart at about shoulder width. Keep your legs in the air and cross your right leg over top of your left leg at center. Return your legs to the starting position before crossing your left leg over your right leg. Bring it back to the starting position and repeat the whole motion again. The final motion in your five minute workout will be the bicycle crunch.  This move will require some coordination and will target your core and can also engage your legs to some degree.  Try to do the motion as quickly as you can while maintaining proper form to get the most from this movement.  Start by laying flat on your back with your hands up behind your head. Raise both your right leg and left elbow up to try and make them meet.  Use your core during the lift. Repeat the motion on the other side of your body, bringing your left leg up to meet with your right elbow. Continue this exercise for the full twenty seconds.
Know what to expect from the workout. Do some squat jumps. Work in mountain climbers. Add hip raises. Do high knees. Move to windshield wipers. Do some yoga push ups. Work in ski jumps. Add a reverse bear crawl. Use the scissor exercise. Finish with the bicycle crunch.