• Basic situps, often performed at a gym, can be just as easily performed at home without equipment.Man exercising sit-ups image by Elzbieta Sekowska from Fotolia.com
  
  For many people trying to improve their bodies, one of the biggest problem spots is the tummy or abdominal region. There are many muscle-building and toning exercises you can do without equipment in the comfort of your home. But be aware that building and toning muscles in the tummy area takes hard work and dedication to achieve results.
  
  

Crunches and Variations

• Crunches are probably the most basic abdominal exercise. Lie on your back with your knees bent at a 45-degree angle and your feet flat on the floor. Put your hands behind your head for proper support, and, using the muscles in your abdomen, raise your torso to the knee and gently lower your body back to the floor.
  
  For added difficulty, still lying on your back, raise your legs into a chair-sitting position. For better support, use a couch or chair, which are often the appropriate height. To work on your side abdominal muscles, twist your body in either direction while bringing your torso toward your knees.
  
  

Leg Lifts

• Leg Lifts are performed by lying on the floor with your hands gently at the small of your back. Raise your legs about 6 inches off the floor at a 45-degree angle. Lower them while keeping your heels 6 inches from the floor. Repeat. Your feet should not touch the floor until you complete the exercise.
  
  

Butterflies

• Butterfly exercises are more extreme leg lifts. Lie on your back with your legs extended and hands gently at the small of your back. Lift your legs about 6 inches off the floor. Raise your legs to a make an "L" with your body. Bring them back down to about 6 inches from the floor. Spread your legs apart, creating a "V" with your legs at the 6-inch height. Bring them back together and raise them again to create the "L." Go back and forth from "L" to "V" five to 10 times.
  
  

Frog Kicks

• This exercise with a fun name is very difficult. With your hands folded at the small of your back, lie on your back with your legs extended. This should be the last time your legs touch the floor until the end of the exercise. Bring your legs up without bending your knees so that they are perpendicular to your body. Bend the knees, bringing them close to your chest, and slowly extend them again. Repeat this exercise several times.
  
  

Leg Raise

• Do not attempt this exercise without proper equipment. The leg raise requires a chin-up bar or a gym that has a leg-raise machine. Hang on the bar or machine and support all of your weight with your upper arms, keeping your body in a straight, hanging position. Without bending your knees, lift your legs into an "L" position and then gently back down. Repeat this exercise several times for an optimal abdominal workout.