The defender met up with the rest of the squad for the first time since joining the Tigers from Birmingham City last month.
The 28-year-old told the club's official website: "The first day was good and we did a little bit more than I expected.
"It was a very thorough first day and it took around three hours to go through all of the tests. As I'm still in the process of moving up to Hull, that was great and better than just coming in for a quick run. It was fantastic to get so much done.
"I would say this was the most thorough first day of pre-season I've experienced. It was basically a full medical and more for everybody. It was nice to meet up with the rest of the lads and we're looking forward to getting into the hard work."
Davies made 106 appearances in all competitions in three seasons with Birmingham.