The decline bench knee raise is a good exercise to hit your lower abs. Grab a decline bench and set the angle to around 30 to 45 degrees.

Lay on the bench backwards, with your head the highest end.

Hold onto the pads above your head for stability.

With your feet and knees together, point your legs out straight so your body forms a straight plank. Your legs should not be resting on the bench. This is the starting position for the exercise.

Execute by slowly pulling your knees up towards your chest as high as possible.

Pause, then slowly lower back to the starting position.

Repeat for desired reps.

Knee Raise Tips:

Do not swing your knees up. Use your abdominalmuscles to move your legs - not momentum.

Increase intensity by holding a dumbbell between your feet and/or pausing for a count of two at the top of the exercise.