Horton has a decision to make
MACK Horton will attempt to replicate his Rio success in the 400m freestyle to kick-start Australia's campaign in the pool and help decide his future heading into the Tokyo Olympics.
With the 800m freestyle to be added to the Olympic program in 2020, Horton must decide whether to specialise in the middle-distance events or continue to chase a place as one of Australia's distance swimming greats.
Horton has enormous respect for the 1500m and its position in Australian swimming history but is yet to snare a major title in the event, and he is the Olympic champion over 400m.
While plenty of swimmers have doubled up in the 400m and 1500m, the addition of the 800m for Tokyo will make it increasingly difficult to manage a multi-event program and Horton knows a decision is looming.
"It's tough, I think," he said when asked if the 1500m was still his priority.
"Looking forward to Tokyo, which is ultimately the goal, the 800m is now in there, so I have to find a balance between the 200m, 400m, 800m and 1500m and where I sit.
"I think we'll get through these Games and Pan Pacs (in Japan in August) and then we'll have to make a decision on where we sit going forward to Tokyo.
"It's something that we're thinking about but we haven't decided yet."
Horton's Olympic success in the 400m in Rio and continued improvement in the 200m may dictate he concentrates on the shorter events.
"I'd like to get better at the 200m," he said.
"One of my favourite moments from Rio actually (is) anchoring that (4x200m) relay.
"Before Tokyo, I'm going to have to make a decision of where I sit."
Horton heads into the opening day's 400m freestyle holding the fastest time in the world in 2018, with his 3min 45.41sec win at trials last month.
But the lack of early season races in Europe skews the rankings and he will face a tough challenge from England's James Guy, Scotland's Stephen Milne and Australian teammates Jack Cartwright and David McKeon.
McKeon, the silver medallist behind Canada's Ryan Cochrane in Glasgow four years ago, sees room for improvement in his 400m after what he regards as a sub-par performance at trials.
"The times weren't that quick in the 400m and I wasn't too happy with that," McKeon said.
"But you don't have to be fully rested (at the trials), you've got to be fully rested and ready to go (at the Games)."
Having worked hard on his fitness, McKeon wants to rediscover the easy early speed that had him head out in the 400m at the Glasgow Games trials well under world record pace.
"The last few years I've been working a lot on my fitness and my back end (but) I've got to be able to get out stronger and better than I have in the past couple of years and get back to swimming with front-end speed.
"Once I've freshened up for the Games I'll be able to put together a pretty strong performance."