If you're thinking that jumping rope is only for school girls, get a clue! Some of the toughest athletes in the world, namely boxers, UFC fighters, as well as others, jump rope to shed pounds, stay in shape and help with everything from posture to coordination.
Not often thought of by lay people as an alternative to jogging, biking or elliptical cardio routines, jumping rope can burn some serious calories- about 225 calories every 15 minutes for an average 150 lb. individual! The best part is, you can do it practically anywhere, it doesn't cost much (a typical leather or plastic speed rope costs about $15) and work almost every muscle of your body. Jumping rope will help work your calves, glutes, quadriceps, shoulders and wrists, as well as less obvious core muscles of the lower and upper back and abdominal muscles. One must remain almost bolt upright to do the exercise properly which promotes good posture.
The key to doing it properly is to jump only enough to clear the rope when it passes under your feet. Don't jump higher than this as it will not work your leg muscles as effectively. An inch off the ground is usually perfect. Also, be sure to land and jump off the balls of your feet. The combination of the low jump and landing on the balls of the feet will help minimize the impact on the knees and avoid injury. It forces one to use "finesse" and to be lighter on one's feet. Many tennis players have used jumping rope as a method to increase endurance and be light on their feet. The straight jump with two feet up and down simultaneously is the simplest technique.
There is also the alternating method, where you put one foot on the ground at a time, alternating between right and left, while having both feet off the ground as the rope passes under you. There are many other styles as well, and I'd suggest purchasing a cheap book on the subject to get more ideas and break up the monotony. How long a rope should you use? Ideally, if you hold the rope handles with both hands and step on the center of the rope, the handles should reach your mid chest. Also, as far as the turning motion goes, the main driver should come from your wrists, not your elbows or shoulders. The exercise forces you to use energy in the most efficient way possible. Using poor technique will hamper endurance and increase the possibility of injury.
As far as giving you a workout is concerned, it might be one of the hardest exercises out there. The first time I tried it, I was good for about 3 minutes before I was huffing and puffing and had to stop. Practicing it will definitely improve your endurance and technique. If you belong to a gym, I advise jumping rope on a smooth flat surface in front of a full length mirror to actually see what you're doing. An aerobics studio is perfect. Also, having music to jump to is critical. An iPod loaded with plenty of upbeat dance music will be very helpful. One technique I tried, was trying to jump without stopping to an entire 5 minute, 30 second song. It took me a while to work up to this but I eventually made it- and beyond!