Yes, it is a very short distance. I'm training out of neccessity for a military school, one of the swims I need to complete is 50m underwater. Currently, I'm doing CO2 and O2 tables every other day, but never getting over about 45 seconds of holding my breath. I don't have a pool around since I'm currently in Iraq, so for now I'm limited to dry land training. I've also been doing some walking apnea. I'm a decent runner, running 25-30 miles a week. I just passed through an obsession with weight training and I feel as though I'm limited by my muscularity, 190 pounds at 5'11", which is something I'm trying to fix since it really hurt my running. So, my question is, for the 50m swim, how long do I need to build my breath holds up to for a safe completion? Also, is the breaststroke/dolphin kick the best method? And when should I do my tables, and walking apnea since I run in the mornings and don't want to do it before that? Also, is there anything I should add to my regime? Thanks very much for any help you have to offer.