You can do speed swimming in any stroke, but you can't put your head into the water when you do resistance test. You must be on the water to see drowning. You must be able to step on the water. Moreover, the difficulty is cardiopulmonary resuscitation. Most people are brushed off by CPR. There will be a 7-day training after registration, but personally, it is best to tread water, drag backstroke and jump into the water.