Underwater training in Hawaii was part of Alex Smith's vacation routine

ST. JOSEPH, Mo. -- Alex Smith and his family took advantage of his recent break from football to vacation in Hawaii. It obviously wasn’t all fun and games for the Kansas City Chiefs quarterback.

Smith’s wife Elizabeth recently tweeted a couple of pictures of Smith’s workouts while in Hawaii. They don’t look like much fun. In one, Smith is carrying a large rock while walking on the bottom of the ocean.

Smith arrived at training camp on Tuesday, a day before the Chiefs begin a three-day minicamp for quarterbacks and rookies. He said the underwater training isn’t anything new for him.

"I’ve done forms of that probably the last five years," he said. "This is probably the most consistent I've done something like that. I was doing it pretty regularly over the whole month of July. It's just something fun. We do get out to Hawaii for a few weeks and it's fun to kind of incorporate being outside and not just in the gym."

Smith and his family ended their stay in Hawaii a few days ahead of when many of his veteran teammates would have needed to. The Chiefs require their veteran quarterbacks, including backups Tyler Bray and Aaron Murray, to participate in the minicamp.

Smith isn't complaining, perhaps in part because he can't tote large rocks at the bottom of the ocean while in Missouri.

"I love coming early with the rookies," Smith said. "You just can’t simulate throwing 11-on-11 for this last month. You play catch, try to find guys here and there and throw so you can stay ready.

"For us to have a few days here … you do kind of get up to speed pretty quick and shake a little bit [of rust], if you did have any rust. You get cranked up for a few days, and then when the vets come in you kind of hit the ground running."

Participating in a camp mostly for rookies and young players gives Smith a chance to throw to some receivers he didn’t get the chance to work with during offseason practice and might not throw to during full-squad training camp, which begins on Saturday. Smith did a lot of his practice throwing in the spring to first-team receivers such as Jeremy Maclin, Travis Kelce and Albert Wilson. They will be his most frequent targets at camp.

But for three days, Smith gets a chance to work with receivers such as Demarcus Robinson, a fourth-round draft pick.

"As a 12th-year guy with kids and stuff, sometimes it's hard, and when football is done I head home," Smith said of practicing in Kansas City. "So it’s nice to kind of have a few days with the young guys, especially to kind of spend some time with them and get to know them."