What's your favorite form of cardio exercise?  We're asking because for today's workout in our No-Excuses Workout Challenge, all we ask is that you keep your heart rate up for 30 minutes.  Take that studio cycling class you love.  Go for a run.  Hit the pool for some laps.  It doesn't matter what you do, just keep moving for 30 minutes

If you would like a little more direction, we have some workout plans for you to try — one using a treadmill and one using an elliptical, in case you have access to some cardio equipment.

Treadmill

Elliptical

*SPM = Strides per minute

Set incline to 20 percent

If you've been playing around with how to do Headstands and Forearm Stands, Handstands are another fun inversion to try.  If you have your heart set on getting upside down, here are eight moves to practice.  They'll help you build strength and stability, so you'll be standing on your hands in no time!

Push-Ups

It may seem like Handstands are all about balance, but in order to be able to hold your body straight upside down, you need major upper-body strength.  Push-ups are by far the best exercise since they'll target your arms, shoulders, upper back, and core.  Basic push-ups work great, but you can strengthen other areas of your body by throwing some push-up variations into your weekly routine as well.

Backbend Push-Ups

Here's another push-up variation that will really target your shoulders and upper back, as well as your quads and core.  It'll also get you used to being upside down.  Do three sets of 10 a few times a week, and you'll really notice a difference in your upper-body strength.

Headstand

Since the Handstand is a pretty advanced inversion, it's good to work on the most stable inversion first, Headstand.  Try this one known as Bound Headstand to build your strength and balance.

Forearm Stand

After mastering a Headstand, a Forearm Stand is the next hardest inversion, but not as hard as the Handstand.  Since you're resting on your forearms, there's more surface area to balance on.  Do this move in front of a wall at first to prevent falling, and then move to the middle of the room.

Crow

Crow pose is a great next step since it requires upper-body strength, balance, and core strength.  It's like a little mini-Handstand and a great way to get your hands and wrists used to holding up your body weight.

Handstand Split

Although the goal of the Handstand in yoga is to be able to hold your body in one straight line, it's really difficult to find that balance at first.  Doing a Handstand with your legs in a split position is much easier.  Do it in front of a wall with your toes leaning for support, and eventually move away when you master the balance.

Handstand Against the Wall

Here's the next step in being able to do Handstands freely.  Place you hands six or so inches away from the edge of a wall.  Kick your feet up, press the top of your head against the wall, and move your legs away.  This will get your body in the correct alignment with your hips and shoulders stacked.  Hold this position for as long as you can, and you'll really feel your core and upper body working hard to keep your body up.  When you're ready, start pulling your head away from the wall, balancing in a full Handstand.

Handstand

After mastering Handstand against the wall, you're ready to move to an open area to work on balancing without any help.  Kick up with control into Handstand Split, and slowly scissor your legs together.  Concentrate on holding your gaze at one point on the floor below you, keeping the hips stacked over the shoulders, fingers spread wide.  Hold for as long as you can.

Just in case you were thinking about skipping today's workout, Jillian Michaels wants to remind you that it's not only your conscience you have to run from, but zombies too!

We knew The Fitness Marshall wouldn't come through San Francisco without doing a dance routine in front of the Golden Gate Bridge; and that's exactly what he did.  Join Caleb with his backup booties Bria and Haley with a little throwback hip hop from Missy Elliott — these moves will totally make you lose control and lose yourself in the sweat sesh,

If you want to burn 100 calories in 10 minutes, and tone your tush and legs at the same time, go for a run.  For even greater lower-body-sculpting power, you'll need to add hills to your workout.

I know.  I know.  Hills suck!  And if running up hills is way too challenging, walking briskly will do the same magic.  This interval workout combines walking hills and short sprints with just a bit of incline to reduce the chance of developing shin splints.  Aside from a toned tush and thighs, intervals are also proven to target belly fat, so it's doubly effective.  In about 40 minutes, you'll burn over 400 calories!

Set the treadmill incline to one, and get started!  For each three-minute brisk walking interval, you'll need to raise the incline to 15 percent (or as high as it'll go), and for each 60-second sprinting interval, you'll need to lower it to one.  Adjust the speed as necessary if either the walking or sprinting pace seems too slow or fast.

Total calories burned:  416

*Calories burned calculations are based on a 130-pound woman