Punishment is an external force.
Discipline is self-imposed.
The difference is parallel to that of inspiration and motivation. We can inspire others to action, but motivation, ultimately, comes from within.
Discipline is the same way. We can offer a workout program, a daily calendar full of to-dos, build a tracking app, require a player to do certain things, and this might inspire them to find the discipline to do the things you want them to, but discipline itself comes from each of us.
Help others to find the discipline, even require the actions to be a part of your program. That’s opportunity, not punishment.
Coaching Made Easier 