Bosu

If you haven't already, learn to love lunges. They are the ultimate exercise; you can do them anywhere, anytime and see (bikini bottom) results fast. This compound exercise works your entire leg and is an easy addition to both your cardio and weight workouts. Once you've mastered the basic lunge, speed up the process to long, lean legs with the addition of a BOSU.

Here's how:

• Standing it front of the BOSU, engage your core. Keep your upper body straight with your shoulders back and relaxed.
• Similar to the position of a basic lunge, bring your right leg behind you, placing it on the BOSU.
• With control, lower your hips until both knees are bent at about a 90-degree angle. Make sure your front knee is directly above your ankle and your right knee doesn't touch the floor. Keep the weight in your heels as you push back up to the starting position. This completes one rep.
• Do two sets of 10 reps on each side.

It's not glamorous, but the BOSU, that unassuming half-ball prop at your gym, is a workhorse. Not only can you use both sides of it (which is how its "both sides used" name was coined), but you can also pick it up to add even more dimension to your workout routine. If you've been ignoring the stack of BOSUs in the corner of your gym for far too long, then here are three ways to incorporate the BOSU (or a similar balance-challenging prop) into your routine!

Get unstable: The BOSU makes any workout more difficult, and that includes the ones that are seemingly simple but oh-so effective. The next time you're doing an exercise move, add the BOSU to the mix; everything from a simple deadlift to a side lunge suddenly becomes harder as you use your different muscles to steady yourself on the BOSU. If you need ideas, then try these balance exercise on the BOSU.

Seated ab moves: Spice up even more of your normal everyday moves by sitting on a BOSU instead of the floor. These two-move sequences add the BOSU to traditional seated twist moves make you work your abs that much more.

Change your plank: Those plank moves are always more challenging than they look! But if you're ready to take it to the next level, then use an upside-down BOSU as your planking surface (hold on to the sides), and then do this twisted plank sequence on the BOSU. You may not like it while you're doing it, but you'll thank us later!

Do you use a BOSU or other balancing prop?

Once you've mastered the basic moves of strength training — like squats, lunges, and planks — gym time can become a little dull. Workouts creep by slowly due to boredom, and if you don't push yourself to the next level, you may find your fitness level stalling as you coast onto a plateau. When the going gets boring, it's time to get unstable.

Performing seemingly simple exercises on an unstable surface creates a whole new set of challenges for you to master. Fitness tools like the BOSU, balance pads (sponge-like pads, two to three inches thick), rocker boards, and exercise balls can help you work out harder by disrupting your sense of balance. If you're ready to experiment with instability, here are a few exercises my Equinox trainer has recently taught me.

• Plank on the rocker board: There are a wide variety of rocker boards, but for this move the one we use looks like an over-sized skateboard with a cylindrical piece attached in the middle. I place my hands equidistant from the center and hold a plank, trying not to dip to either side. When that becomes somewhat easy, add alternating leg lifts. This move seemed impossible to me at first, but once you find the zone on the third set you feel a core master.
  Hold the plank for 30 seconds; do 10 lifts on each leg.

Learn two more moves after the break.

No matter how you slice it or dice it, the BOSU makes everything harder — and I mean that in a good way. Take your basic plank, add the BOSU into the equation and your core is working overtime. Here's a progression of plank exercises for this devilish piece of equipment that I learned from my Equinox trainer Lauren.

1. Basic Plank: You start in a basic plank with the ball side of the BOSU facing down. This can be quite a challenge and an exercise unto itself. If just doing this plank variation, hold the position for 30 to 60 seconds, and repeat three times.
2. Knee Up: For an added challenge, while holding the plank pull your right knee to your chest and hold there for two or three seconds. Return to the plank, and switch legs for one complete rep. Do 10 reps altogether. You need to keep the BOSU stable throughout the exercise — that's what makes it tough.
3. Add a Twist: Start in plank, pull your right knee toward your chest, twist to the left, and kick your right leg out to straight. Reverse the action, untwist, bring knee to chest, then return to plank. Do 10 times on each side. This one is tough, but it makes more sense to your body on the second set. Do two to three sets of this move while keeping the BOSU stable.

Motherhood is a balancing act so a BOSU balance trainer ($130) is an appropriate device for moms to use when they are fighting the postpartum pounds! Our friends over at Equinox set me up with Amy Fiske, an NSCA-certified personal trainer, who is helping me get back in shape. Here are some of the BOSU exercises she recommends.

BOSU Hip Raise
(Targets the glutes and hamstrings)
Lie face up with your knees bent and feet flat on the BOSU. Raise your hips up toward the ceiling by squeezing your glutes and pressing down through your heels. Try to imagine a straight line going from the top of your knees to your shoulders. Hold for a few seconds and then return to your starting position.

BOSU Plank
(This targets the core)
Lay flat on your stomach, position your elbows under the shoulders on top of the BOSU, then curl your toes under and push your body up by resting your weight on your elbows and tightening your torso. This can be done by pulling your navel in toward your spine so your hips don’t sag. Your body should be in a straight line from head to heels. The neck should be kept in-line with the rest of the spine. Keep breathing naturally throughout the exercise. Hold for about 30 seconds. Make the exercise less challenging by holding this position on your knees or by placing your forearms on an elevated surface. Make it more of a challenge by adding in a leg lift.

Keep reading for two more exercises.