R is for Rectus Abdominis

The rectus abdominis is the most well-known and prominent abdominal muscle within the torso. It is a long and flat muscle that extends vertically between the pubis and the 5th, 6th and 7th ribs.

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This muscle is also known as the ‘6-pack’ although there are actually 8 sections, but the lower 2 are not easily seen so it is rarely known as ‘8-pack’. What gives this muscle the look of being a 6 or 8-pack set is the strong tendinous sheath, the ‘linea alba,’ also known as the ‘white line’. This sheath divides the rectus abdominis down the middle. There are 3 more horizontal tendinous sheaths which give the muscles the ‘washboard’ look which can be seen on very fit people with low body fat, such as athletes.

People are usually very keen to get toned abs or a 6-pack and think that by doing hundreds of abdominal exercises such as crunches this will happen, but unfortunately this isn’t the case. We have a layer of fat above our muscles so unless you have a very low body fat percentage it will be really difficult to see the rectus abdominis for the average person.  You will eventually see some results by losing weight and performing strengthening exercises but this won’t happen overnight!  Remember it’s important to have a balanced exercise programme which works opposing muscles groups, so the back muscles as well as the abdominal muscles.

The job of the rectus abdominis muscle is to flex the spine. It also plays a part during lateral flexion of the spine and side bending movements as well as assisting in stabilising the trunk.

In 30-40% of pregnancies the rectus abdominis separates to allow for the growing baby. This is called ‘diastasis recti’. Having more than one child can make this condition more likely, especially if they are close in age. It is also more likely if a mother is over 35 years of age or if she is having heavy babies or twins/triplets.  Women aren’t usually aware of this happening although some can feel discomfort in the latter part of the pregnancy such as a stretching sensation. For a caesarean birth (or C-section) the surgeon will pull the rectus abdominis muscles apart to access the uterus and deliver the baby or babies! Post pregnancy, the separated muscles will close after a while. This can be within 6 months although it can take up to a year and in some cases the muscles will never close completely. A small separation of about 1 cm is fine but if there is still a large gap then women are advised to see a physiotherapist or Pilates teacher to help with strengthening these muscles and closing the gap. In some cases surgery may be needed as the gap can cause lower back pain and in severe cases hernias.  Men can also get this, usually from yo-yo dieting or poor technique when performing sit-ups or doing heavy weightlifting incorrectly.