There are those who would suggest that disciplines are a form of legalism; I have to heartily disagree. Discipline, at least as I have experienced in my life, is rather the condition in which freedom becomes possible. Let me explain.
My lazy body does not wish to exercise. Never has and I suspect it never will. But when the body's desire is over-ruled and I force it three times a week to do what it does not want to do, I suddenly see that I am free and no longer in bondage to my body's inherent laziness.
My heart does not wish to pray. Not as it should, and my mind can always come up with other things that I need to be doing instead. But when the heart or mind is told: Hush, now is the time of prayer, and I follow the discipline of daily matins and vespers, I find myself free again. Freed through the Word that is heard and free to pray, even when I don't feel like it - and just like the exercise, when it is done, I find that I ended up feeling like it a great deal!
My palate never thinks that a single glass of wine is sufficient. Hasn't done so for a long time. I'd like two or three. But when that desire for more is overruled and the thirst is told: this much you get, no more, I suddenly find myself free again. I didn't HAVE to have those extra glasses at all.
I have no idea if this makes any sense to anyone else, but to me in my life disciplines have been anything but legalisms. I don't pretend for an instant that they make me more pleasing to God - how can anyone be more pleasing to God than one already is through the self-oblation of our beloved Lord Jesus Christ, our Eternal High Priest? Instead, I see that these disciplines have freed me from behaviors that used to trap me and hold me in bondage. This holds in so many areas of life that I can't even begin to enumerate them all.
My plea: do not mistake disciplines for legalism and leading to bondage. In fact, they lead to the opposite.