1. FLOOR CRUNCH

TARGETS Rectus abdominis

MAXFIT SAYS "This is a basic move, but it can be difficult for some beginners to really hit their rectus because it’s easy to bring the hip flexors into play," says Dakota Mitchell, a certified personal trainer and former fitness model.

SET-UP Lie on your back on the floor with your knees up and your feet on the ground. Place your arms across your chest or behind your head near your neck. Begin with your upper back off the ground.

ACTION Raise your upper body toward your knees using the power of your abs and avoid pulling at your head or neck. "You only need to move a few inches," says Mitchell. When you reach the midpoint, crunch down on your abs. Then, without releasing your abs, stretch back to the starting position.

INTENSITY TIP You can raise your feet off the ground with your knees a little farther from your upper body than your hips. You can also hold a small weight at the back of your head as you perform the set.

2. BALL CRUNCH

TARGET Rectus abdominis

MAXFIT SAYS This is one of the most basic moves, and it is excellent for beginners and experienced individuals because you can control the amount of work and intensity of each rep.

SET UP Lie on the ball, as shown. Your upper legs should be parallel to the ground-depending on your height and the size of the ball-and your lower legs should be braced against the ground at an angle that allows you to maintain control and feel the move in your abs.

ACTION Contract your abs and curl your upper body up using the power of your abs, keeping your lower body stationary. As you approach the upright position, force a deeper contraction in your midsection. Hold that contraction for a moment; then without releasing your abs, stretch back to the starting position.

INTENSITY TIP Perform the same movement with your feet on a wall, about 12 inches off the ground. You can also hold a small weight behind your head for added resistance.