In Stitches

Monday I spent some time with our 12 & under age groupers putting them through their paces in dryland. Their dryland includes some running, ab exercises, and some body-weight strength exercises like push-ups, squats, etc.

The run required them to complete eight lengths of an approximately 80m distance back and forth along an outdoor corridor near our pool. Ignoring my instructions to start at warm-up speed and go faster each length than the one before, they took off on the first length sprinting for all they were worth. Interestingly, as they returned to the place where I stood after 2, 4, and 6 laps, several of them began complaining of a pain in their side.

As a runner for the past 13 years, I know that pain well. In the running community, we call it a "side stitch." Watching these kids get stitches just 30 seconds after beginning exercise got me thinking. What is a side stitch exactly and why does it happen? I did a little research and the answers I found were interesting.

A stitch actually has a scientific name, exercise related transient abdominal pain (ETAP). Pain from a stitch can be under the ribs, behind the back, or even in the shoulder and can lead some to believe they are having a heart attack.

There are essentially 3 theories about the causes of the "side stitch":

1. Tugging of the spleen, stomach, and liver on the underside of the diaphragm. The diaphragm is the muscle that pulls the bottom of your lungs downward on inhalation. The spleen, stomack, and liver are all held in place in the abdomen by ligaments attached to the diaphragm. Vertical displacement of these orgams (like during running) causes spasm in the diaphragm as the ligaments pull at it from below. Apparently, side stitches occur most often on the right side, presumably because that is the liver's location (it has the largest mass of the three). Maximum tugging would occur as the runner's foot strikes the ground when the diaphragm is at its highest point, during full exhalation. This all makes perfect sense to me, but does it explain why stitches can happen during swimming, too?

2. Diaphragmatic ischemia. This means there is a lack of blood flow to the diaphragm, causing it to cramp or spasm. Basically, the lungs and your internal organs pinch the blood vessels leading to the diaphragm.

3. Wikipedia says that imbalances in the thoracic spine can cause a stitch, but doesn't elaborate. I suppose this is due to some unnatural tugging on internal organs due to things being misaligned.

I was interested to find that the cures for a stitch:

1. Put your hand on it and squeeze. This stabilizes the tendons/organs and prevents the tugging.
2. Lay down on on your back. This will make the stitch go away immediately.
3. Improve your abdominal strength and lower back strength. Could the sudden stitches in our swimmers be an indication that they have weak abs? With this information, our age group coach correctly predicted on the first try which swimmer was the first to mention a side stitch. Interesting, huh?
4. Warm-up gradually and completely before exercising.

Other interesting facts and implications:

One source I found stated that 70% of humans breathe when their left foot hits the ground, and only 30% breathe when their right foot makes contact. Why is this? The rough percentage of right and left handers in the world is somewhere around 90 and 10.

Runners generally breath in a 2-1 stride-to-breath ratio while jogging and a 4-1 ratio while running at a faster pace.

Nowhere did I find anything saying that a stitch should be a reason to stop activity or that any damage would be done by a prolonged stitch. Did you read that, swimmers?

So how does this relate to swimming? And why do swimmers get stitches? I suspect that swimmers get stitches mainly due to ischemia (theory #2) due to shallow breathing during training. It is also possible that the reaching and pulling down motion of free, back, and fly could cause the tugging mentioned in theory #1. Perhaps the aspect of all of this that most piques my curiosity is the relationship of breathing to striding in running, and how this relates to swimming. What percentage of swimmers prefer to breathe on which side during freestyle? Does this relate to their handedness? Is there a correlation between this preference and getting side stitches while swimming?

Don't you just love it when a question leads to not to an answer but to even more questions?