Video from Wyke Coastguard showing the rescue helicopter taking off from the scene

Coastguards faced a challenging rescue in the early hours after a woman suffered an injury taking part in a night-run.

The woman, 40, took a tumble and twisted her knee while competing in the Jurassic Coast Challenge, a popular endurance event along the Dorset coast.

Competitors start out from Poole in the daytime and have a choice of walking or running the full route along the coast to West Bay, finishing in Bridport (100km) or taking on the half challenge from Poole to Weymouth (58km).

The woman suffered ligament damage to her knee after slipping as she came down a hill near Bat's Head west of Durdle Door late on Saturday.

Coastguards and paramedics got to her in the early hours of yesterday after making it to the isolated location by going off-road, but due to the secluded location and difficult terrain the coastguard rescue helicopter was called in to lift her out.

While the woman's injury wasn't very serious, there had been concern she was suffering from the effects of the cold – and it wasn't a straight forward extraction because of the location.

The whole operation took about four hours.

Wyke Coastguard Rescue Team was alerted at just after 1.20am yesterday to help colleagues from the Lulworth team.

They tried to pinpoint the casualty's location in what was initially thought to be the Durdle Door area and at this time it was pitch-black.

They then headed towards Bat's Head using an access via Daggers Gate. Paramedics had to join coastguards in their vehicle as they went-off-road in very rough terrain in the darkness.

A spokesman for the coastguard team said: "Some team members made their way on foot towards the coast path and were alerted to the possible casualty location by a flashing light. The teams made their way to the source of this light and were met by one of the event medical staff who guided the paramedics and coastguard officers to the casualty.

"The casualty was located directly east of Bat's Head, at its very lowest point, which meant extraction by stretcher would have been incredibly difficult. Initial assessment of the casualty confirmed the casualty had likely suffered ligament damage to her knee, and was suffering from the effects of exposure. The casualty was given pain relief and wrapped up whilst an extraction plan was considered.

"Due to the casualty condition, and inhospitable location, the best course of recovery was deemed to be by helicopter."

The coastguard helicopter was scrambled and once on scene, the woman was packaged into a stretcher and put aboard. She was taken to the landing site at Dorchester before being taken by ambulance to Dorset County Hospital for further treatment.

The coastguard team were stood down shortly after 5am.