The little red book says that the big-eyed frog is best at swimming backwards.

Backstroke has the following functions:

1. Lose weight. When swimming backstroke, the water will quickly take away the body's heat, which has a good effect on promoting metabolism and reducing weight and lipid. In addition, backstroke consumes the most calories in an hour and is the fastest exercise.

2. Exercise your muscles. Backstroke is also called backstroke. In the process of backstroke, latissimus dorsi will work harder, which can exercise muscles.