- Transverse abnominis is a muscle layer of the front and side abdominal wall which layered below the internal oblique muscle. It is said to be a significant component of the core. This muscle helps to compress the ribs and viscera, providing thoracic and pelvic stability. It also helps a pregnant woman to deliver a child. Training this muscle alone will not give a flat belly and the best exercise to strengthen this muscle is the vacuum exercise. This muscle also involuntarily contracts during many lifts. Asanas that can help is Marjariasana (cat stretch) and Adho Mukha Svanasana (downward facing dog). This muscle is vital to back and core health.
- Rectus abdominis, known as “abs,” is a paired muscle running vertically on each side of the anterior wall of the abdomen. The two are separated by a midline band of connective tissue called the linea alba. While the intersections that run horizontally are actually what cause the appearance of a “six-pack” in people with low body fat and a well developed rectus abdominis. This muscle is an important postural muscle as it stabilises the spine. It is responsible for flexing the lumbar spine and also assists with breathing and keeping the internal organs intact and in creating intra-abdominal pressure, such as when exercising or lifting heavy weights or during childbirth. Asana that helps stretch this muscle is Urdhva Dhanusara (full wheel pose).
- External oblique is the largest and the most outermost of the three flat muscles of abdomen. It is rarely visible especially in females due to fat deposits and the small size of the muscle. It helps in puling the chest downwards and press the abdominal cavity and also actions in both flexion and rotation of the vertebal column. Crunch, side-plank and sit-up can help strengthen this muscle. Parivrtta Trikonasana is one of asana that could help strengthen this muscle.
- Internal obllique is a muscle in the abdominal wall that lies below the eternal oblique and just above the transverse abdominal muscles. It is an accessory muscle of respiration and rotates and side-bend the trunk by pulling the rib cages and midline towards the hip and lower back of the same side. Asana that helps strengthening this muscle is Utthita Parsvakonasana.
Below is the summary of origin, insertion, actions and asanas that help strengthening each one of these four muscles.
JW – 200h YTT Jan-Apr 2016