Looking at the Spring trends that emerged at New York Fashion Week [1], we're seeing lots of exposed shoulders and racerback necklines paired with flowy skirts and loose pants. This open-shoulder look that Eva Longeria recently wore [2] on The Late Show With Stephen Colbert exemplifies the trend perfectly. We are not here to talk fashion, but this trend is an indication that backs are the new butt. Let us explain.

For the past few years, the Internet seemed almost soley obsessed — fitness wise — with workouts to tone, lift, and sculpt the butt for a fuller, firmer derrière to rock the tight-fitting body-con looks; but it's time to move the focus upward and start working the back and shoulders. This is not to say we should abandon glute work. Having a strong butt is important [3] for your overall fitness (and to rock a bikini). Remember, defined deltoids create a sculpted shoulder and can make your waist look smaller too.

When it comes to strength training, the back is often neglected; what you can't see in the mirror doesn't need to be worked, right? Wrong. There is a tendancy to focus solely on the abs, but true core strength involves your entire torso — back included. When the abs and the back work in tandem, the body as whole moves more effiently, placing less stress on the hips, knees, and ankles.

Also consider the amount of time we spend hunched over keyboards, steering wheels, and cell phones and what it does to our bodies [4]. Our back muscles and the connective tissue in the spine tend be over stretched and weak, and this wreaks havoc on your posture. Slouching not only leads to back and neck pain, but it can also adversely affect your digestion since it squishes all your organs as they work hard to process food into energy. On the vanity tip, slouching can also make you look up to 10 pounds heavier.

Now that you know why you need to work your back and shoulders, here are four moves that do just that.

Bent-Over Row

This exercise is great for working the upper back and opening the chest. Plus it strengthens and tones all the muscles around the shoulder blades to sculpt a seriously sexy upper back.

• With a pair of dumbbells and your feet hip-width distance apart, bend at the waist. Keep your back parallel to the floor with a neutral spine — not rounded.
• With a slight bend in your knees, hold your arms and the dumbbells extended out in front of you.
• Engage your abs and squeeze your shoulder blades together as you bring the weights to your torso. Be sure to keep your elbows in and pointed upward.
• Slowly lower the weights back to the starting position to complete one rep.
• Do two to three sets of 12 reps.

Reverse Fly

We love what this move does for the upperback and the back of the shoulders. To protect your shoulder joints, use lighter weights than you do for a reverse row.

• Holding a dumbbell in each hand, stand with knees slightly bent. Keeping your back flat, bend forward at the hip joint. Rotate your palms up to open the shoulder joint.
• Exhale and lift both arms to the side, maintaining a slight bend in the elbows and squeezing your shoulder blades together. Then with control, lower the dumbbells back to your starting position.
• Do two to three sets of 12 reps.

Straight-Arm Triceps

The exercise not only tones the back of the upper arm, but it works the back of the deltoid to define the shoulder as well the largest muscle of the back — the lats.

• Holding a pair of dumbbells with your feet hip-width distance apart, bend at the waist. Keep your back parallel to the floor with a neutral spine — not rounded. Palms should be facing each other.
• Keep your torso stable as you raise your arms behind you, squeezing your shoulder blades together. Hold the position for a moment.
• Lower your arms back to starting position to complete one rep.
• Do two to three sets.

Twisted Hyperextension

Along with working the spinal muslces, this twisted extentsion exercise tones the love handles by engaging the back fibers of the obliques as well as the rhomboids, the muscles that pull the shoulder blades together. It's a great exercise for improving posture.

• Lie face down your your mat, with your elbows bend and finger tips pointing toward your forehead.
• Keeping your feet on the floor and your abs pulled to your spine, squeeze your shoulder blades together as your arch your back bringing your head and chest off the floor.
• Maintain the arch as you twist your upper back to the left, feeling your left chest open. Without lowering your chest, twist to the right. Return to center and lower your upper body to the floor.
• Repeat for a total of 10 reps, alternating the starting side.
• Do two to three sets and take a Child's Pose [5] to stretch your back after sets.