Exercise Related Transient Abdominal Pain (ETAP)

Ever felt a localized pain on one side of your abdomen while running? This is known as an exercise-related transient abdominal pain (ETAP) or also known as a stitch. Mild stiches are similar to a cramp or an ache. Severe stiches can be a sharp or stabbing pain.

The causes of these can be due to muscle spasm in your diaphragm, a parietal peritoneum irritation, or stress on the spine. When you are expanding and contracting your diaphragm quicker than normal or stretching beyond its usual limits, more work is done than what the diaphragm is used to which is why it is commonly felt in less experienced runners.

The parietal peritoneum is a thin membrane that lines the abdominal and pelvic cavities in your body. When the membrane is irritated by movements in the abdominal wall, pain sensations can be perceived.

Shallow or chest breathing can also contribute to a side stich. When you take short breaths, the muscles in your body may not receive enough oxygen and become fatigued more easily. Shallow breaths can also put more stress on your muscles as it needs to work harder to compensate.

Below are a few tips to prevent or stop side stiches:

1. Slow down

Try to slow your pace and change the rate of your breathing.

2. Practice belly breathing/ diaphragmatic breathing

Focus on how you take your breaths. Avoid shallow or chest breathing while running. Inhale and exhale fully and deeply.

3. Warm up / Enhance your core strength

Do a proper warmup before running to stimulate blood flow and prep your muscles. Do some arm stretches overhead, include some reaching and rotating of your torso to warm up the muscles surrounding your diaphragm.

Stiches are common for runners and most people get through it with deep breaths, stretches or for some they need to stop exercising to alleviate the pain. If you are experiencing side stich pain during rest or for a prolonged period of time, please seek medical advice from your doctor.

Reference: Morton D, Callister R. Exercise-related transient abdominal pain (ETAP). Sports Med. 2015;45(1):23-35. doi:10.1007/s40279-014-0245-z