Whether it’s just a threatening twitch in the side or an all out, doubled-over abdomen-ripping pain – the stitch strikes down athletes of all calibres and in a surprisingly wide range of sports. But what causes it and how do we prevent it?

Australia’s Dr Darren Mortan is an expert in “Exercise Related Transient Abdominal Pain” and has been carrying out leading edge research in this area. Dr Mortan is the Director of the Avondale Centre for Exercise Sciences and a lecturer in the Department of Health and Physical Education at Avondale College NSW.

Just how common is the stitch?

Research indicates that about 70% of regular runners have experienced stitch within the past year (1), but it is also common in other sports including swimming, team sports and even horse riding. Stitches aren’t sexist either – they affect both men and women although young people are more likely to get one than older people.

Woman on running track has stitch during workout

But what causes it?

Until recently it was believed that stitch pain was caused by a lack of blood to the diaphragm or it was due to stress on the ligaments that attach the adominal organs to the under-side of the diaphragm. The theory suggested the ligaments were stressed during jolting activities such as running. However, it was found that some people experience stitch low in the abdomen, some distance from the diaphragm (2). Furthermore, many swimmers experience it, a sport not characterised by jolting actions.

Dr Mortan’s research suggests the parietal peritoneum, which lines the entire abdominal wall extending up under the diaphragm, is the culprit. This appears likely because a stitch can occur at any site throughout the abdomen. The parietal peritoneum is also known to be sensitive to any movement when irritated, explaining why stitch pain typically disappears when exercise stops. The type of pain arising from the parietal peritoneum – sharp or stabbing and capable of being pinpointed – is also consistent with a stitch. Plus when irritated under the diaphragm, the parietal peritoneum causes shoulder-tip pain, the same aching or sharp pain athletes often call ‘stitch in the shoulder’.

It is believed the problem is friction on the membrane. Stomach bloating after eating and drinking, or the large bowel being distended, could place more pressure on the parietal peritoneum causing friction.

Research has found that different fluids move through the stomach at different rates. Hypertonic solutions that are high in sugars (that is greater than about 8% carbohydrates) like fruit juices and soft drinks, are more likely to cause a stitch because they move slowly, meaning more fluid in the gut that could cause swelling and friction.

These drinks may also contribute to stitch by dehydrating the membrane. The body draws fluids into the gut to dilute hypertonic solutions. If that reduces the fluid that covers the parietal peritoneum it could lead to more friction.

These drinks may also contribute to stitch by dehydrating the membrane. The body draws fluid into the gut to dilute hypertonic solutions. If that reduces the fluid that covers the parietal peritoneum it could lead to more friction.

How do we avoid stitches?

  • Drink plenty of isotonic fluid (6% carbohydrates like Gatorade) in the 24 hours leading up to the event.
  • Refrain from consuming large meals 2 to 3 hours before activity.
  • Avoid extremely sugary foods and drinks like fruit juices and soft drinks.
  • When consuming fluids during activity, drink smaller amounts at regular intervals.

And if you’d like further information on what to eat before, during and after working out, please see here.

References

(1) Mortan, D.P., Richards, D & Callister, R (1999). Epidemiology of ‘stitch’ at a community run/walk event (abstract). Medicine and Science in Sports and Exercise. 35(5): S262 (suppl. 1272).

(2) Mortan, D.P. & Callister, R. (2000). Characteristics and aetiology of exercise-related transient abdominal pain. Medicine and Science in Sports and Exercise. 32(2): 432-438.