Christchurch cyclist Keagan Girdlestone is breathing again following a horrific crash in Italy.

Christchurch professional cyclist Keagan Girdlestone has regained consciousness following a horrific crash in Italy earlier this month, but his long-term health is unclear.

A post on his Facebook page on Monday [NZ time] said the 19-year-old was breathing on his own after being placed in an induced coma.

He was having some difficulty breathing as one of the nerves controlling his diaphragm had been damaged.

Keagan Girdlestone won the 2014 Le Race, event from Christchurch to Akaroa, becoming the youngest winner in history at 16 years old.

Girdlestone, originally from South Africa, came close to death on June 5 after suffering serious injury in a high speed crash with a support vehicle in the Coppa Della Pace race, near Rimini in northern Italy.

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He crashed through the rear windscreen of the car after it braked suddenly and later experienced a cardiac arrest while in hospital.

The post said Girdlestone did not sustain any facial injuries, contrary to initial reports.

"The critical injuries were sustained to his neck and throat. He severed not only the carotid artery, but the jugular vein, nerve and muscles."

"Due to major loss of blood at the scene, as well as the time it took to get him to surgery, the right hand side of his brain was starved of blood and oxygen. He also sustained bruising of his brain due to the impact as well as vocal cord damage."

The full extent of his injuries was unknown, as well as the period of rehabilitation.

"He has limited movement of his left side due to the lack of oxygen to the brain, however this is showing signs of improvement. The right side, which is being affected by nerve damage, is also limited. He is able to move his leg and squeeze his hand, but there is no movement of his arm.

"With continued rehabilitation it is hoped that all functionality will improve as time passes. However, any possible long term effects are still unknown."

Girdlestone's parents, Wayne and Desere, left Christchurch for Italy not knowing what condition they would find their son in.

The promising cyclist shot to prominence in 2014 when he became the youngest winner of the 100km Le Race event from Christchurch to Akaroa, when he was just 16.

He rides for South Africa's Dimension Data team, a feeder team for the WorldTour set-up.

Team Dimension Data principal Douglas Ryder told CyclingTips they had been blown away by the support Girdlestone had received.

"The support that he has got around the world just shows what a close community the cycling community is, which has just been amazing.

"His parents are there with him now and they read the messages every single day. Chris Froome sent a video message to him. People in the third division of cycling win races and they say that they are wishing Keagan all the best."

Girdlestone's past results include fourth in last year's junior world time trial championships, as well as a stage win, plus the overall victory in both the 2015 Tour du Valromey and the 2015 Ronde des Valles.

Two-time Tour de France winner Froome has been just one of many cyclists to offer encouraging messages.

Top British sprinter Mark Cavendish left a video of support on his Facebook page, while Kiwi cyclist Greg Henderson also tweeted "Good luck Keagan. Focus on the positive" following the crash.

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