背泳ぎ

1. Origins, structure, and basic meaning

• Structure: 背泳ぎ(せおよぎ) combines 背(せ) and 泳ぎ(およぎ) and means backstroke, swimming on one's back.
• Basic usage: It names a swimming stroke or practice using that stroke.

2. Common pitfalls and similar expressions

• Particles for stroke and distance
  • In 背泳ぎで二百メートルを泳ぐ, で marks the swimming method and を connects the distance covered. In 背泳ぎの腕の動かし方, の specifies arm movement within that stroke.