Boxing: Anthony Joshua 'takes training to new depths' as he swims with 25kg weight ahead of Joseph Parker showdown

Anthony Joshua has been 'taking training to new depths' ahead of his fight with Joseph Parker. Photo / Instagram

For Anthony Joshua, beating Joseph Parker will require more than the usual sessions on the pads and the punchbags.

The British heavyweight, who holds the IBF and WBA world titles, will face the WBO king in a historic unification clash in Cardiff on March 31.

And ahead of the meeting of the two unbeaten fighters, Joshua has been employing some rather unorthodox training exercises.

On Wednesday AJ uploaded a photograph that showed him swimming underwater with what is thought to be a 25kg plate along the pool's floor.

'Taking training to new depths,' the British fighter wrote alongside the picture on his official Instagram page.

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Five thousand miles away, New Zealand's Parker is undertaking a gruelling camp of his own in the Las Vegas desert.

Under the tutelage of trainer Kevin Barry, Parker is currently training in his adopted home as he looks to extend his professional record to 25-0 in Cardiff.

But Joshua is the heavy favourite for the unification clash, having won all 20 of his fights by knockout since turning professional in 2013.