鍛える

1. Origins, structure, and basic meaning

• Structure: 鍛える (きたえる) is a transitive verb for strengthening the body through training or forging metal by working it.
• Basic usage: 足腰を鍛えている is continuing physical exercise; 鉄を打って鍛えた is completed work on heated iron.

2. Common pitfalls and similar expressions

• Training the body and forging metal
  • Both targets take を, but 足腰 selects skill or strength development and 鉄 selects material processing. The progressive and past forms also differ in time.