Troubling Achilles injury trend across professional circuit that has left Alexander Zverev 'afraid'

A concerning trend of Achilles injuries across the ATP Tour has left Alexander Zverev "afraid", with the German citing his fear as reason for his choice to call for a medical timeout in the second round of the Australian Open.

Zverev looked slightly off pace in his battle against Alexandre Muller on Wednesday, but it did not stop him from claiming victory 6-4, 4-6, 6-3, 6-4 in a rain-affected match.

The German star is still hunting his first grand slam title, but the road to achieving that goal looked to be under a dark cloud as he called for medics to come to the court.

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Zverev was leading the fourth and final set 2-1 at the time when he alerted the umpire that he needed assistance and began walking towards his chair.

It was initially unclear to all exactly what was troubling Zverev as he had shown little signs of discomfort while moving to his seat.

However, it eventually became clear that he was concerned by an issue in his lower leg.

A short break in play took place as he received assistance, although he did not appear to be in too much discomfort or pain as the physio conducted his assessment.

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In fact, Zverev admitted post-match that all he need was a painkiller to assist him through the pain and push through the match to claim victory.

"I took a painkiller and it was fine after that," Zverev revealed post-match.

"I am not somebody who takes a lot of medical timeouts, so I was a bit scared because it was my Achilles tendon.

"There have been a lot of Achilles injuries over the past couple of years on tour. I was just a bit afraid and wanted the physio to check it out."

Achilles injuries have been among the leading causes for players to hit the sidelines in recent years in tennis, with Holger Rune the last high-profile player to be impacted.

The Danish star underwent surgery on his Achilles in October and has yet to return to the tour.

Often the injury has placed a dark cloud over players careers, however, there have been many cases where players have returned to action after an extended layoff. Australia's Storm Hunter is one of those cases.

Still, Zverev is erring on the side of caution to ensure he stays fit and healthy.

"After the medical time out I was moving and playing fine," he continued.

"I hope [on Thursday] that it will be fine as well."

Zverev will return to action in the third round against Cameron Norrie.