Updated June 19, 2014.
Answer: Although it may feel as though you can "isolate" the upper and lower abs (the rectus abdominis), you actually can't contract one section independent of the other. Research that looked at the muscle activation while performing a basic crunch exercise found that you may feel more contraction in the upper abdomen because the muscle fibers in the upper part of the rectus abdominis shorten more than in the lower part of the muscle, but the entire muscle is, in fact, activated during the movement.
When you perform a reverse crunch (lifting the hips), the opposite happens; you feel more contraction in the lower part of the rectus abdominis even though the muscle fibers in the upper rectus abdominis are also contracting.
Additionally, when you stabilize the hips and only lift the torso during the crunch, there is greater muscle involvement in the upper rectus abdominis as well as the internal obliques. When you perform reverse crunches, there is more activation the lower part of the rectus abdominis and more involvement of the external obliques.
Question: Can I Lose Belly Fat by Doing Lots of Crunches?
Updated June 19, 2014.
Answer: Unfortunately, no. Simply doing lots of crunches won't reduce reduce belly fat. The belief that you can lose body fat in a specific area by exercising the muscles just beneath that fat is called "spot reduction." Spot reduction is a myth that has been disproved time and time again.
In 1984, researchers at the University of Massachusetts concluded that abdominal exercises do not decrease the amount or size of belly fat.
In this study men did the equivalent of 5,000 sit-ups for 27 days. The researchers measured body fat in the abdomen, buttocks and upper back during the study. If spot reduction worked, the men should have lost fat only in the abdominal area because the buttocks and upper back are not worked during sit-ups. However there was no change in the thickness of abdominal fat or waist size. Biopsies showed there was no significant change in the diameter of abdominal fat cells either.
What ab exercises can do is tone and firm the muscles, but to reduce abdominal fat takes more than just ab exercise. You need a balanced fitness routine that includes cardiovascular exercise, resistance training, and a sensible diet.
Question: What Is the Best Abdominal Exercise?
Updated June 19, 2014.
Answer: One study that looked at the best and worst ab exercises concluded that:
- The Bicycle Crunch Exercise was the best for strengthening the rectus abdominis
- The Captain's Chair Exercise the best for strengthening the internal obliques and the external obliques
However, it's important to keep in mind that there is no single abdominal exercise that challenges all the abdominal muscles in the most effective way, and the best way to work the abs is with a variety of abdominal exercises as explained in the next FAQ.
Question: Does the Order of Ab Exercises Matter?
Updated June 19, 2014.
Answer: Although some programs insist that the order of abdominal exercise is the key to getting results, there is no research that backs this up. In fact, research shows that the opposite may be true. The principle of adaptation explains how our body constantly adapts to new training routines. Over time and with practice we become very efficient and master these techniques. If you continue to do the same exercise, in the same order in a few weeks or months the routine becomes ineffective and we hit a plateau.
To break this cycle, modify your routines every 1-3 months. To modify your exercise routine, change one of more of the following:
- The Specific Exercises Performed
- The Number of Repetitions or Sets Performed
- The Order of the Exercises
- The Number of Exercises Done Each Session
- The Amount of Weight or Resistance Used
- The Speed, or Tempo of the Exercises
Question: Can I Use Weights When Exercising the Abs?
Updated June 19, 2014.
Answer: Yes, but before you add resistance with weights you should be able to perform the exercises properly with good technique. The most effective ab exercises start with proper body position, controlled movements and focus on contracting the specific muscles you want to work. Better results come from slow, controlled repetitions. Once you have good form, you can begin adding small hand held weights or a medicine ball to increase the resistance.
Question: How High Should I Lift Up During a Basic Crunch?
Updated June 19, 2014.
Answer: When performing the basic crunch exercise lift up until your shoulder blades come off the floor. Research shows that the abdominal muscles can flex the spinal column to about 30 to 45 degrees of movement. Beyond 30 degrees, the powerful hip flexors are activated to a higher degree than the abs. Because this is a relatively small range of motion, it's helpful to perform many repetitions of the basic crunch to get a full ab workout or to add additional ab exercises.
Question: How Often Should I Do Abdominal Exercises?
Updated June 19, 2014.
Answer: No research to date has found any benefit from doing abdominal exercises more than 3-5 times per week, however, it's not harmful to work your abs everyday. It's difficult to fatigue or overwork the abs by performing standard body weight exercises due to the limited resistance through a small range of motion. If you work your abs with resistance, you should allow a day of rest between workouts.
Question: What's the Best Pilates Exercise for the Abdominals?
Updated June 19, 2014.
Answer: In 2005 researcher Michele Olson presented the results of a study that measured abdominal muscle activity during five Pilates mat exercises. Participants performed the Pilates exercises and also performed basic crunch exercise for comparison. Her results showed that the abdominal muscles were activated during all five Pilates exercises. However, the Teaser exercise and Roll-Up challenged rectus abdominis muscle more than the basic crunch.
The external obliques were activated more during all of the Pilates exercises when compared with the basic crunch. The Criss-Cross Exercise (also called the Bicycle Crunch), in particular, was the most effective for the external obliques. The Teaser exercise also activated the hip flexors to a fairly substantial degree and should be saved for the very fit athlete.
Updated June 19, 2014.
Answer: Although the hip flexors are the prime movers in the Captain's Chair Exercise (hanging leg lift), the abdominals are still contracting in this exercise. During this movement, rectus abdominis contracts statically (without movement) and helps rotate and stabilizing the pelvis. In many cases the rectus abdominis is maximally contracted to stabilize the pelvis while you lift the legs toward the chest.
This exercise is generally done with bent knees. Performing this exercise with straight legs creates a tremendous load on the lumbar spine and is only recommended for very fit athletes.
Updated June 19, 2014.
Answer: Unfortunately, many people have the misconception that holding hand weights and doing side bending exercises will trim or tone the "love handles." However, this movement (lateral flexion) is performed mainly with the deep muscles of the spine and not the internal obliques or the external obliques. Instead, the quadratus lumborum muscle, which attaches from the iliac crest to the lumbar vertebrae and to the lowest rib, is actually a primary lateral flexor muscle.
What this exercise is good for is increasing lateral range of motion in the spine. If you do side bending exercises, make sure they are slow and controlled movements.