I want to know the answer to the following question:
What did Jahn promote the use of?
All the background I'm provided with is that "In the late eighteenth- and early nineteenth-century Germany, three pioneer physical educators – Johann Friedrich GutsMuths (1759–1839) and Friedrich Ludwig Jahn (1778–1852) – created exercises for boys and young men on apparatus they had designed that ultimately led to what is considered modern gymnastics.". Is that enough to answer the question?
Answer: no