Often pole vaulters will go through a spell of simply not being able to take off. No matter how hard they try for some reason it just doesn't happen and can be very frustrating. Some unknown psychological block or fear prevents taking off. Beth Harris explains some tactics to cure pole vault take off refusal.
Take off refusal problems happen to every athlete at some point during their career, as they grow and become stronger, if their body shape changes, all these things can effect how they feel at take off. In order to cure this it take a lot of paitence, taking pressure off and avoiding competitions, potentially breaking down the vault agin to rebuld confidence. Making it fun and achievable in different ways with different challanges so it is enjoyable will also help.
Some athelets will benifit from having a break at the end of the competition season as Pole vaulting is a mentally challaning event and this can give time to regroup and come back to it.