A former member of the RAF who broke his neck during an "It's a Knockout" type event at an air force base has had his bid for £6m damages turned down.
Robert Uren was 21 when he dived into an inflatable pool to retrieve plastic fruit at an event at RAF High Wycombe, Buckinghamshire, in July 2005.
He had sued the MoD and Corporate Leisure to cover the care he will need after he was left tetraplegic.
The judge Mr Justice Field said: "Such activities are almost never risk-free."
Mr Uren, of Camborne, Cornwall, was taking part in a relay race in which service personnel had to retrieve plastic fruit toys from the bottom of an inflatable pool, the High Court was told.
His QC, Sir Geoffrey Nice, said Mr Uren had taken an awkward and "uncontrolled dive" into the pool, to avoid other competitors, but slipped on either wet grass or the surrounding mats.
He caught his legs on the side and cartwheeled forward, striking his head on the bottom.
Mr Uren, a senior aircraftsmen who joined the RAF at 18, suffered damage to the spinal cord and is permanently wheelchair-dependent.
The judge said he had the "greatest sympathy" for Mr Uren.
However, he added: "Enjoyable competitive activities are an important and beneficial part of the life of the very many people who are fit enough to participate in them. This is especially true in the case of fit service personnel.
"Such activities are almost never risk-free.
"This means that a balance has to be struck between the level of risk involved and the benefits the activity confers on the participants and thereby on society generally."
The judge concluded that neither the MoD, nor event organisers, Corporate Leisure (UK) Ltd, were "obliged to neuter the game of much of its enjoyable challenge by prohibiting head first entry (into the pool)."
Mr Uren said earlier that joining the RAF had been a boyhood dream and he still had hopes of returning to the forces in some capacity or working as an electronics engineer.