It happened on the B3081 near Verwood - he had to be cut free by firefighters.
Warning About Rock Falls And Landslides
Police are warning people to take care watching the sailing events at Weymouth - after two men were injured yesterday (Thursday 9th August).
They were hurt after slipping on rocks underneath Not the Fort.
They were flown to hospital with head and leg injuries.
Meanwhile, five people escaped unhurt after a major rock fall along the Jurassic Coast near Charmouth on Wednesday 8th August, the Coastguard said.
The warning comes just two weeks after Charlotte Blackman, 22, died when she was crushed by 400 tonnes of rock that fell on her at Hive Beach in Burton Bradstock during a cliff fall. Miss Blackman, of Heanor, Derbyshire, was on holiday with her family and boyfriend just 10 miles from Wednesday's incident, when tragedy struck.
Landslips and rockfalls are common along that part of the south coast but heavy rainfall combined with the recent heatwave has left some of the cliffs in West Dorset in an unstable condition, with a potentially heightened risk of additional landslides, mudslides and rock falls.
Additional warning signs have been put up along the coast, and additional public notices are being prepared for tourist information centres and other strategic points in the area.
Wednesday's alert was raised by the crew of a boat who saw the people on the beach between Charmouth and Golden Cap, despite all the recent public warnings.
The Lyme Regis and West Bay Coastguard rescue teams, the Coastguard rescue helicopter from Portland, RNLI Lifeboat and Dorset Police all attended the scene.
When the emergency services arrived the five people seen by the ship were quickly accounted for and they were asked to leave the area due to the continued risk. It was established that there were no other people missing.
Maddy Davey, Portland Coastguard watch manager, said:
''The cliffs along the West Dorset coast are very unstable following the extensive rain earlier this year and in certain areas it remains extremely unsafe to walk along the beach.
''We are especially concerned about the risk after the death which happened in July at Burton Bradstock.''
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