Stitch: Causes and How to Avoid It

A stitch is a nuisance that can slow down your performance. It's not dangerous, but definitely annoying. The question is, what really causes a stitch, and what can you actually do to reduce the risk? Here, we explore what research says about the possible mechanisms behind a stitch, why it's more common in some sports, and why it doesn't seem to be the same thing as a cramp. The conclusion is that a stitch is likely related to mechanical irritation in the abdominal area and can be influenced by how close to the activity you eat and drink, as well as core stability and posture. With the right routines, many can significantly reduce the problem.

This is, of course, the first question we must ask ourselves. Stitch, or side cramp as it's also known, is a vague pain in the abdominal region. The pain is often localized, but it doesn't occur in exactly the same spot for everyone.

In a study, 848 runners and walkers were asked after a 14 km race in Sydney if they experienced a stitch and, if so, where. The results are shown in the image below.

Three-quarters of the participants ran the race while a quarter walked. In total, 27% of participants experienced a stitch. Among these, stitches were twice as common for the runners compared to the walkers. Furthermore, 42% of the participants reported that their performance was limited by the stitch. Other studies indicate that 10-20% of all runners experience stitches during competition. So yes — it's a nuisance we'd like to eliminate.

As the image shows, the sides, just under the ribs, are the most common area affected. Hence the name side stitch. In most cases, the pain intensifies if you keep moving: it becomes sharper and more localized until you stop, after which the pain usually disappears immediately.

Stitch is somewhat like cramping — researchers can't precisely determine why we experience it. However, they're making progress. It's more common with stitch in sports that involve body twisting, especially in the core, or activities that cause jarring or bouncing, suggesting that core movements play a role.

The most likely cause is irritation in the peritoneum and the ligaments attached to the diaphragm, caused by continuous stretching of membranes and ligaments, for example, when you run. This particularly applies to our visceral ligaments that hold the stomach, liver, and other organs in place.

There are many theories. One common belief is that our internal organs "bounce" during activity. However, stitches are also frequent during swimming, where the bouncing isn't quite the same. On the other hand, research measuring muscle activity in the abdominal region shows that when a stitch occurs, no difference in muscle activity is observed—there is no extra fatigued muscle like you see with a cramp. That's why it's important to distinguish between cramps and stitches: cramps are more related to muscle fatigue, while stitches seem to be more about irritation in non-contractile structures, like the peritoneum and ligaments.

Fluid intake before and during activity can increase the risk of a stitch, especially if you drink a lot in a short period. However, just as the gut can be trained to absorb more carbohydrates and reduce the risk of stomach problems, it can also get accustomed to fluid intake during exercise.

"While fluid consumption appears to provoke ETAP, fluids may be better tolerated with practice. Reliability testing conducted by Morton et al. [20], which involved subjects exercising on several occasions after consuming large volumes of fluid, found that the experience of ETAP decreased in the later trials. Just as the gut may be trainable with regards to digesting and absorbing fluids during exercise [30], this may suggest that sufferers of ETAP might benefit from practicing fluid consumption during exercise."

Try reducing fluid intake slightly until you do not experience a stitch. Gradually increase it, together with a progressive carbohydrate intake, and see if it gets better. Avoid highly concentrated sports drinks if you are prone to stitches.

A strong inner core can definitely make a difference. Greater stability in the core means less bouncing of the organs and, in turn, less irritation on the ligaments and peritoneum. During activities like heavier deadlifts, certain visceral ligaments are also stressed, which can enhance their resilience and lower the risk of stitches. Considering that even poor posture increases the risk of stitches, it would be smart to train the core.

So don't skip out on core training.

As an additional note, running stride and surface can also make a difference. A running stride with less bounce or a softer surface that better absorbs impacts can be beneficial.

The theory of mechanical stress and irritation of ligaments around the abdomen and peritoneum is the most probable explanation. However, it has weaknesses — for instance, a stitch can also occur during swimming, where the same mechanical influence isn't evident. Much like cramping, a stitch can be multifactorial, arising from various factors. Still, the movement of our organs during activity appears to be a contributing factor.

Avoid eating and drinking right before activity and don't overlook core training. These strategies can help significantly. Naturally, you can consume something light or drink a little beforehand if you need to top up your energy or maintain fluid balance. However, avoid drinking 0.5 liters of water 10 minutes before starting if you're prone to stitches. In our article on fluid intake, you can find more information about fluid absorption and how much you can absorb per minute (hint — 36 ml/min as sports drink, 10–12 ml/min as plain water).