Basically the issue with the knees is you don't want to start riding a horse too strenuously until the knees close. For each breed it is different. Some close at 3, others, like drafts and WBs, can wait until 5 or so.
the act of making or enacting laws. 2. a law or a body of laws enacted. Origin of legislation.
Legislation Vs Regulation. Legislation is a directive placed by a government or governing body on either an industry, a section of community or placed on people of a country which must be complied with in order to remain within the legal boundaries of that particular country, community or industry.