Donald McCain is still trying to find a definitive reason for Overturn's disappointing display in the Kingwell Hurdle at Wincanton on Saturday.
The 2010 Guinness Galway Hurdle winner was a major contender for the Grade Two event on the back of a fine second to Binocular in Kempton's Christmas Hurdle.
But having deployed his regular front-running tactics, he weakened rapidly to finish last of the five runners.
'We scoped Overturn immediately after his race at Wincanton and, along with his heartbeat, everything checked out fine,' explained McCain.
'Obviously it was a disappointing performance, but he was pulling his lad round the stable yard 30 minutes after the race and we will run some further tests to cover everything off.
'During the race, he never seemed to be going as well as he can in front - Jason (Maguire) said the ground was extremely holding, which could have been a contributing factor.'
