Bad Nauheim/Hamburg, Aug 2 (DPA) Michael Schumacher's planned comeback to Formula One for this month's European Grand Prix in Valencia is putting pressure on his doctors to ensure the Ferrari driver is fit enough to deal with the rigours of the sport.

'It's an exceptional situation for us because nobody had planned with preparing such an intensive training programme,' Johannes Peil, whose team at the Bad Neuheim sports clinic has treated Schumacher for the last nine years, told DPA.

Normally a driver has months to get in shape but the 40-year-old Schumacher only has three weeks until the race in Valencia, Aug 23, when he will replace the injured Felipe Massa in the Ferrari

cockpit.

'We have an emergency programme in place until Valencia, after which time a standard one will come into operation. Everything is important but we only have a limited time to complete everything,' he said.

'It's only because Michael has done so much in his sport since he retired is a return even possible. Even after a break of three or four weeks, a Formula One driver needs some time to adapt correctly to the extreme pressures.

'It affects the spinal chord as well as the lower arms and hands. No training is a substitute for the experience of driving in a racing car.'

Schumacher's fitness programme involves up to four physiotherapy sessions a day as well as endurance and other exercises designed specifically for F1 drivers.