1, thunderstorm, summer noon, physical discomfort, underwater danger, etc. I can't swim in water.

2. Don't go swimming immediately after eating too much, drinking wine, exercising vigorously and not warming up.

3, should go hand in hand, go swimming in pollution-free safe waters, the water quality is clear and blue, and there are no harmful and toxic organisms.

4. Warm up before launching, from upper limbs to lower limbs, to prevent injuries and cramps.

5. Inhale through the mouth on the water surface and exhale through the mouth and nose; Exhale through the nose and mouth underwater, but you can't inhale.

6, the water is too cold, swimming for a long time or suddenly exerting your feet, it is easy to cramp your legs.

7, leg cramps just inhale and lean back, straighten and lift the cramped legs, grab the toes with both hands and pull a few times to the chest.

8. When going ashore temporarily, dry the water on your body with a bath towel and put on a bath towel to protect yourself from the sun.

9. There are drugs and germs in the water, so go home and take a soap bath.

10, winter swimming should be practiced from autumn, and swimming time should not be too long.