The vacuum exercise is an exercise which involves contracting some internal abdominal muscles, primarily the Transversus abdominis muscle

Transversus abdominis muscle

The transversus abdominis muscle, also known as the transverse abdominus, transversalis muscle and transverse abdominal muscle, is a muscle layer of the anterior and lateral abdominal wall which is deep to the internal oblique muscle...

, and not as much the diaphragm, the "six pack

Rectus abdominis muscle

The rectus abdominis muscle, also known as the "six pack", is a paired muscle running vertically on each side of the anterior wall of the human abdomen . There are two parallel muscles, separated by a midline band of connective tissue called the linea alba...

" muscles or "abs" which are trained through crunches, leg raise

Leg raise

Leg raise is a strength training exercise used for strengthening the abdominal muscles and hips.Leg raises without equipment are done by lying on the floor on the back. Keep the lower back in contact with the floor and place hands to sides or under lower back for support. Lift legs upward as far as...

s, or other core exercises.

Repetitions of the exercise may be used as a form of endurance training

Aerobic exercise

Aerobic exercise is physical exercise of relatively low intensity that depends primarily on the aerobic energy-generating process. Aerobic literally means "living in air", and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism...

, and light strength training

Strength training

Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...

. There is difficulty building strength in the muscle, as resistance training

Resistance training

Resistance training has two different meanings. A broader meaning that refers to any training that uses a resistance to the force of muscular contraction , and elastic or hydraulic resistance, which refers to a specific type of strength training that uses elastic or hydraulic tension to provide...

 is difficult for internal muscles.

The reasons for performing this exercise vary. It has been done cited for aesthetic purposes in bodybuilding

Bodybuilding

Bodybuilding is a form of body modification involving intensive muscle hypertrophy. An individual who engages in this activity is referred to as a bodybuilder. In competitive and professional bodybuilding, bodybuilders display their physiques to a panel of judges, who assign points based on their...

 competitions (to suck the abdomen in, making it appear less bulgy). It can be done to enhance overall core stability and strength. It is used in belly dance

Belly dance

Belly dance or Bellydance is a "Western"-coined name for a traditional "Middle Eastern" dance, especially raqs sharqi . It is sometimes also called Middle Eastern dance or Arabic dance in the West, or by the Greco-Turkish term çiftetelli...

 to actively perform flutters, engaging various fibres in the muscle selectively. Some believe the pressures it exerts upon the intestines are an aid to digestion

Digestion

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

. It is used in reverse breathing

Reverse breathing

Reverse Breathing is a breathing technique associated with yoga and qigong. It consists of expanding the abdomen while breathing out through the nose, and then compressing it while inhaling via the mouth -- the opposite of what an abdomen would do during natural, instinctive breathing. Via this...

 upon exhalation.

People may also sometimes contract these muscles in public to reduce the appearance of their abdomen, consciously or unconsciously. "Sucking in" the stomach to appear thinner may be most common form of this exercise, but with little of the intensity, positive thinking, or long-term purpose of the other forms.

Performing a vacuum

In performing a vacuum (activating the transverse abdominis), one draws one's bellybutton inward, toward the spine. Some perform a vacuum in conjugation with bending over, reaching overhead, or when lifting heavy weights, although the benefit and healthiness of this is disputed (some advocated just tensing the midsection, with primary focus more so on the lower back). Increasing the range of motion (how far it is drawn in), the intensity (very little can be done, other than resisting gravity) or the duration are the methods of making the muscles stronger. Performing flutters or tabatta intervals of high intensity and rest similar to kegel exercise

Kegel exercise

A pelvic floor exercise, more commonly called a Kegel exercise , consists of contracting and relaxing the muscles that form part of the pelvic floor, which are now sometimes colloquially referred to as the "Kegel muscles". Several tools exist to help with these exercises, though many are ineffective...

s is also common. It may also be possible to vary the pressures by contorting the body or exerting various pressures on tissues connected to the transversus abdominis, although how this might be done is currently unknown.

Yoga method

In the Hatha yoga

Hatha yoga

Hatha yoga , also called hatha vidya , is a system of yoga introduced by Yogi Swatmarama, a Hindu sage of 15th century India, and compiler of the Hatha Yoga Pradipika....

 asanas known as cat stretch and Adho Mukha Svanasana

Adho Mukha Svanasana

thumb|right|Downward-Facing DogAdho Mukha Svanasana, Adho Mukha Shvanasana , Downward-Facing Dog Pose, Downward Dog, or Down Dog, is an asana.- Etymology :...

, the exercise can be performed while on all-Fours so that the muscles must resist gravity, making a slight difference in the resistance required.

String method

A method of developing long-term daily endurance in the muscles is to tie a string around the waist at the bellybutton level. The string is tied at 3/4 of one's maximum vacuum point. The string should be tight, but not noticeably cutting into the skin. When the transverse abdominis relaxes, the abdominal wall (belly) expands and the string will tighten for immediate feedback, reminding the user to contract the TA.

Vacuum Exercise in Popular Culture

"My berliner (a pet name for my gut) dropped three radii with positive thinking, a few vacuums a day, and a kegel for good measure" - Davy Stiler, Ph.D.

"One day I kegeled til my prostate hurt. That is when I discovered the vacuum. At first it was just an interim replacement, but now has become part of my daily spiritual journey" - Myron L. Dallie, Philanthropist