She said she had coped with the trauma of the Everest deaths by using "mental discipline".

BBC: Annabelle Bond at summit of Vinson Massif, Antarctica

Add the mystical mental discipline of a samurai warrior, if I can also force myself to perform more than one or two tai chi swings.

WSJ: The Punishment of Winter Workouts | Golf Journal by John Paul Newport

Graham reinforced the importance of hard work, discipline and the appropriate mental approach to the game of baseball.

FORBES: A Fond Farewell To Yankee Stalwart Andy Pettitte

The queen of studies embraces all of life, including psychology and the social sciences, but philosophers think of themselves as engaged in an intellectual discipline, characterised by argument, which, even if it settles nothing, is a splendid mental workout.

ECONOMIST: Pacifier philosophy