When personal trainer Lucie B. says jumping rope is just what the doctor ordered, she should know, because she is a doctor. This physician turned fitness guru holds a degree in medicine and a national championship title for speed and power jump rope.

"After winning a gold medal at a regional power-jumping contest in 2002, I left medicine and never looked back," Lucie B. says. "I decided to dedicate my life to helping people get fit by jumping rope." She's now one of the top instructors at the New York Health & Racquet Club, a premier fitness-center chain based in New York City.

The way Lucie B. teaches it, jumping rope is one of the fiercest fitness experiences you'll ever have. It's a supereffective way to burn fat, increase stamina, improve coordination and firm muscles. It's a speedy calorie burner too — you can burn more than 200 calories in just 20 minutes, as much as running a 10-minute mile but with half the impact on your knees and ankles. As she puts it, "You get a killer upper- and lower-body workout that really kicks butt!"

So if you're ready to learn the ropes Lucie B.-style, check out this Turn and Burn class, which she created especially for iVillagers. Do it two to three times a week, and you'll feel leaner, stronger and faster in six weeks.