Triceps pushups are a very challenging exercise for the back of the arms. Like traditional pushups, they challenge a variety of muscles in the body (not just the triceps)...what makes them different is your hand position on the floor. By using a narrow hand-placement, you can really target the triceps muscles. This variation is shown on a ball, though you can do them on the floor as well.

• Kneel in front of the ball and roll forward until the ball is under the mid-upper thighs (the further out you are, the harder this move is).
• Place the hands shoulder-width apart and place them just below the chest.
• Bend the elbows and keep them close to the body and facing the back of the room as you lower down into a pushup in a see-saw motion (i.e., don't bend at the hips)
• Push back to start and repeat for 1-3 sets of 10-16 reps.

Pushup with Side Plank

Yet another way to spice up traditional pushups is to engage the core even more with an added side plank. By doing a pushup and rotating into a side plank, you'll build strength and endurance in the arms and shoulders, since balancing your body weight on one arm is much harder than on two. The rotation fires the obliques and even the legs work harder to keep you stabilized. For a modification, you can try this exercise on your knees as well.

• Begin in a pushup position, on the hands and toes (or on the hands and knees, if you're modifying). Make sure the core is braced and the body is in a straight line from head to heels.
• Bend the elbows and lower into a pushup.
• As you push up, rotate to the left, taking the left arm straight up towards the ceiling and rotating the feet into a staggered position (left foot in front and right foot in back).
• Hold the side plank for a few seconds, then rotate back to your pushup position.
• Do another pushup and, this time, rotate to the right into a side plank, balancing on the left arm.
• Continue pushups with alternating side planks for 1-3 sets of 8-16 reps (1 rep includes side planks to the right and left).

Chest Press with Dumbbells - Alternating

This interesting variation of the traditional dumbbell chest press is more challenging than it looks, especially if you do it on an exercise ball. By alternating the arms, you add a new dynamic to the move where you have to engage your core to keep the body stable. When doing this version, you may need to go lighter on the weights. You might also want to try it on a bench or floor before moving on to an exercise ball.

• Lie down on a bench, step, ball or the floor. Begin with the weights in each hand straight up over the chest, palms face out.
• Keep the left arm in place while bending the right elbow and lowering the arm down until it's at or just below the chest (the arm should look like a goal post).
• Press the arm back up without locking the elbow, then immediately repeat the move on the left arm while keeping the right arm in place.
• Continue alternating sides, engaging the abs to keep the torso from moving.
• Repeat for 1 to 3 sets of 8 to 16 reps on each arm

Start on elbows and knees, locking hands together. Straighten legs and raise your body so that you’re supported by the balls of your feet, with feet hip-distance apart. Face the floor, being careful not to arch your back or stick your bottom in the air. Hold this position for 45 seconds to begin with, extending the time as you get stronger.

Back Extensions on the Ball

Using a ball for back extensions will give you more range of motion than you get on the floor and you'll also have a balance challenge since the ball is unstable. You may want to prop your feet against the wall to get more leverage.

• Lie down with the ball under the belly and hips, legs straight out behind you (or knees bent for a modification).
• Place the hands behind the head or under the chin - you can also keep the hands resting on the ball if you need a modification.
• Round down over the ball and then squeeze the lower back to lift the chest off the ball.
• Raise up until the body is straight (don't hyperextend), lower down and repeat for 1-3 sets of 10-16 reps.

Reverse Fly

The reverse fly is a great way to target the 'posture' muscles of the upper back, including the rhomboids, the trapezius muscles and even the rear shoulders. Because you're bent over, you'll likely need lighter weights than for other back exercises. Keep in mind that the range of motion on this is small as well - you only want to lift to shoulder level rather than straining to pull the elbows up behind the torso.

• Use light-medium dumbbells and begin in a seated position, bent over with arms hanging down and weights under the knees.
• Try not to collapse on the legs but, instead, keep the back straight and the abs engaged.
• Lift the arms out to the sides, up to shoulder level, squeezing shoulder blades together.
• Keep the elbows slightly bent and only lift to shoulders.
• Lower and repeat for 1 to 3 sets of 12-16 repetitions, with a 20-30 second rest between sets.