Trouble breathing

Question
My son is a competitive swimmer (aged 10) and was swimming 200M freestyle, his first length was great but after 3/4 of the way down the second length he almost stopped then struggled to finish the race.  I thought he had swallowed water but he said he felt his lungs stopped working and he couldnt get a breath, he didn't choke he felt his lungs had seized.  This is the second time it has happened although it never happens in training.

Answer
Julie--
This sounds like it could be a combination of things.
First, he may be holding his breath on the first length instead of keeping a steady flow of air into and out of his lungs.  He should breath every 2nd or 3rd stroke to keep the air moving.  The other possibility is the stress factor.  He may be too worried about how well he is going to do or, since it has happened before whether the breathing problem will happen again.  Make sure he is relaxed and having fun when he is competing.  It doesn't happen in training because there is no "race" stress.  He should race the same way he trains, keep it fun and relaxed.
Let me know if this helps,
George