The double, Reg Prince, has not worked since the incident in the Seychelles seven years ago, his counsel Peter Dedman told Mr Justice Owen.
Mr Prince, 57, of Wimbledon, south-west London, is suing Mr Reed for damages, accusing him either of deliberate and reckless lack of care or negligence. Mr Prince fell 12ft on to a coral beach and suffered a double fracture of the spine.
Mr Reed, 55, of Vale, Guernsey, says that the accident happened when he side-stepped or tried to protect himself from an assault by Mr Prince. The judge is being asked to decide the question of liability only. Any damages due will be assessed later.
Mr Dedman said that the damages action was brought 'more in sorrow than in anger'. The pair had been constant companions and had travelled the world together for many years before the incident, which came during a break in filming Castaway on the island resort of Praslin.
'The two men were involved in many escapades and scraps, both on the film set and off, and in many instances there was more swash buckled off the set than there was on,' Mr Dedman said.
Mr Prince did not suggest that the incident in June 1986 was inspired by malice or that Mr Reed considered the implications of what he was doing, Mr Dedman said. Mr Reed probably thought there was sea below the restaurant and that he would come to no harm. In fact, the tide was out.
The two men had had some drink - a lot in Mr Reed's case - before going to La Reserve restaurant with a companion, John 'Ginger' Hughes. Their meal was still being served when Mr Reed started doing handstands. 'He exhibited a tattoo, which he bears on his penis, to other diners in the restaurant,' Mr Dedman said.
'Mr Prince, over the 20 years or so they had been together, had seen all this before.' He walked to the balustrade and was looking out over the sea when Mr Reed picked him up by the ankles. Mr Prince spent three days in bed and was flown home after being diagnosed as having a back fracture.
The hearing continues today.