The Abdominal muscles, and what they do
There are four primary abdominal muscle groups:
Rectus Abdominus: This is the central muscle running down the middle of your abdomen. You use the Rectus to bend forward - or "flex the trunk". Is the "six-pack" muscle.
Internal Obliques: The internal obliques are on the side of the abdomen. You use them primarily for twisting and bending motions.
External Obliques: The external obliques are over the internal obliques. They are used primarily for bending to the side. they are also used in twisting.
Transversalis: supports the abdominal wall and helps form the girdle that compresses the abdomen.
Sit-ups vs. Crunches
A crunch is a very effective, full-range abdominal exercise where you lie on your back, and curl your trunk, moving your chest bone (sternum) towards your pubic area while keeping your lower back on the floor. A sit-up is an outmoded exercise that extends the crunch until your back is vertical. Do your crunches, avoid sit-ups.
Leg Lifts, Knee Lifts, etc.
Although it is undeniable that leg raises or hip/knee bends will cause an isometric contraction of the rectus abdominus, they are exercises of the hip flexors, not the abdominals. The abdominal muscles do not cross the hips, and no amount of hip flexing will give you a full-range exercise of the abs.
Consider combining leg lifts or hip flexing movements with your crunches to increase intensity throughout the range of motion and add variety to your routine.
Getting Results - Guaranteed
There are more ab-machine infomercials - each guaranteeing results - than fundraisers for Dubya (but that's another topic). Although some of the machines are of dubious value, they deliver results for a simple reason: any properly designed, carefully followed abdominal exercise program will yield great results. You may not get that six pack you've always wanted (see the "Three D's", above) but you can have stronger, firmer, flatter abs, better posture, and the look of a fit individual.
Spot Reducing - The Straight Skinny on Love Handles
There is no non-surgical method to remove body fat in just one area. Your body put it there for a reason and will do everything in its power to keep it there. The best method this side of liposuction to reduce your love handles is the can't miss combination of sensible diet and aerobic exercise. Both of these are important components of a fit lifestyle. Just stay with your program, and be patient. Fitness is a lifelong pursuit, not a short term goal.
One note about focusing your exercises on a particular spot - you may get just the opposite effect you are seeking. If you "hit your obliques" by doing a lot of dumbbell side bends or side sit-ups you may end up building large muscles instead of developing a small waist. Balance your routine for best results.
Machines, Accessories , and other Abdominal toys
There are many different abdominal machines on the market. Although it is possible to develop great abs without any equipment, the proper machine could be an excellent addition to your "arsenal", particularly if you are just starting out. Look for a machine that:
Supports your head. Your head is very heavy, making head support very important for beginners. (See Form on the Abs Exercise page)
Emphasizes curls or crunches, and not hip flexing.
Supports and protects your back.
For more information on this subject go to Abs Equipment.
Click on the links below to learn more about studies listed.
Research & Studies
ACE enlisted the help of the experts at the University of Wisconsin—LaCrosse and its Clinical Exercise Physiology program. Led by John Porcari, Ph.D., and Edward Stenger, M.S., the research team first recruited 16 healthy volunteers (eight men and eight women) between the ages of 18 and 24.