I've carefully checked out the context in the book
From Success to Significance by Richard Carswell. More context:
(The Discipline Factor)
Achieving a balance, is the ideal. Never confuse discipline rigidity. True discipline achieves a balance by producing-not pushing; of diligence, not driving. Even discipline needs to be disciplined. Balance hard work and discipline, with leisure and recreation time. This will cause a surge in creativity. For example, Einstein's Theory of Relativity was discovered while he was daydreaming.