10/27/2009 at 12:00 AM EDT
What's harder than fighting the flu
and shaking off injuries? The nine remaining contestants on Dancing with the Stars
will find out this week when they hit the ballroom floor with three new routines
, compete with a group dance and a dreaded double elimination.
"It's been such a tough week because of all the new dances," model Joanna Krupa
tells PEOPLE. "It's definitely nerve-wracking with everything that's going on."
After stars perform the jitterbug or the waltz, the couples will battle it out in the group competition -- dancing the mambo side-by-side until a judge taps them on the shoulder and eliminates them. The first couple to leave gets one point while the last remaining couple earns nine.
"This is going to take a lot of stamina," says Krupa. "The mambo is supposed to last for four minutes so keeping that energy up is one thing and then to be on the dance floor with eight other couples, that's already stressful. Plus, I don’t want to get that tap!"
Unlike previous weeks, the bottom three -- not two -- will have to worry Tuesday night. The couple with the lowest score, based on the judges' scores and fan votes, will be automatically eliminated. The remaining two will do a 40-second dance-off and then judges Len Goodman, Carrie Ann Inaba
and Bruno Tonioli
will determine who else goes home.
"It's all about who can maintain, who can endure, who can take on more than one dance at a time," says Melissa Joan Hart
, who will be performing the waltz with partner Mark Ballas
. "It'll be interesting, definitely a battle."
Hart, who's been feeling a bit under the weather since Thursday night, says her key to success this week is simple: "It's to run as much as possible without over exhausting myself."
"I was prepared for the physical part of this competition," says Hart, who's eased practice pains with hot baths and Icy Hot patches. "Everyone's like, 'You'll lose so much weight. It's such a great workout. It'll be so hard. Are you ready?' But I didn't realize how mental it is too."
What can fans expect this week? A "high-pressure" salsa and an "interesting" group mambo because we don't really have it choreographed," explains Hart. "It's going to be a dance floor full of just going for it. Some of us have it kind of choreographed but a lot of us are just going to be winging it." --Eunice Oh