Lie with your back on the floor, with your hands behind your head and your knees bent.
Place the soles of your feet on the floor and keep your lower back pressed against the floor.
Keeping your neck neutral, exhale as you flex your waist and hips, bringing your chest and the front of your thighs (quads) closer together.
Hold for a count of two.
Inhale as you slowly reverse the motion to return to the starting position.
Repeat for the desired number of repetitions.
Comments and tips
The crunch with leg raise allows you to activate both the upper and lower abdominals, whereas in the crunch without leg raise, the upper abdominals are emphasized. Both the lower and upper body move with this exercise, while only the upper body moves in the crunch without leg raise.
To protect your lower back, keep it pressed against the floor. This will keep your back from arching.
Keep your elbows out to the sides throughout the exercise. If you have difficulty keeping your elbows out to the sides, this may mean that you are using momentum to perform the crunch instead of using your abdominal muscles.
Do not tuck in your chin. Make sure there is space between your chin and sternum. If you tuck in your chin, this may mean that you are using your neck flexor muscles to crunch instead of your abdominal muscles.