Source: Side Stitch: What Causes It and How to Prevent I
tWhether you're a newbie or an accomplished marathoner, side stitches happen. With all of the research we have available, it sounds strange, but we're still not exactly sure why this pain in the rib cage occurs. Some physiologists have theorized that the common side stitch comes from your stomach and other organs bumping into each other as your feet hit the ground. And others speculate it's caused when the ligament that attaches your liver to your diaphragm becomes overstretched. We can't shift the science that occurs in our bodies, but there are some steps to prevent those pesky cramps.
- Don't fill up: Running on a full stomach is never a good idea. And this doesn't just refer to a big meal, it goes for water as well. Staying hydrated is absolutely necessary, but overloading on H2O or a sports drink right before you head off can lead to bad cramps.
- Stretch appropriately: Improper or lack of stretching may be linked