Padhāna: 'effort.' The 4 right efforts samma-padhāna forming the 6th stage of The Noble Eightfold Middle Path i.e. sammā-vāyāma see: magga are: 1 the effort to avoid samvara-padhāna 2 to overcome pahāna-padhāna 3 to develop bhāvanā-padhāna 4 to maintain anurakkhana-padhāna i.e. 1 the effort to avoid disadvantageous akusala states, such as evil thoughts, etc. 2 to overcome disadvantageous states, 3 to develop advantageous kusala states, such as the 7 elements of enlightenment bojjhanga, 4 to maintain the advantageous states.
The Bhikkhu rouses his will to avoid the arising of evil, disadvantageous things not yet arisen... to overcome them... to develop advantageous things not yet arisen... to maintain them, and not to let them disappear, but to bring them to growth, to maturity and to the full perfection of development. And he makes effort, stirs up his energy, exerts his mind and strives; A. IV, 13.
1;What now, o Bhikkhus, is the effort to avoid? Perceiving a form, or a sound, or an odour, or a taste, or a bodily or mental contact, the Bhikkhu neither adheres to the whole nor to its parts. And he strives to ward off that through which evil and disadvantageous things might arise, such as greed and sorrow, if he remained with unguarded senses; and he watches over his senses, restrains his senses. This is called the effort to avoid.
2;What now is the effort to overcome? The Bhikkhu does not retain any thought of sensual lust, or any other evil, disadvantageous states that may have arisen; he abandons them, dispels them, destroys them, causes them to disappear. This is called the effort to overcome.
3;What now is the effort to develop? The Bhikkhu develops the factors of enlightenment, bent on solitude, on detachment, on ceasing, and ending in deliverance, namely: awareness or mindfulness sati investigation of the law dhamma-vicaya energy viriya rapture pīti tranquillity passaddhi concentraton samādhi equanimity upekkhā This is called the effort to develop.
4;What now is the effort to maintain? The Bhikkhu keeps firmly in his mind a favourable object of concentration, such as the mental image of a skeleton, a corpse infested by worms, a corpse blueblack in colour, a festering corpse, a corpse riddled with holes, a corpse swollen up. This is called the effort to maintain; A. IV, 14.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.