By changing an activity to keep it challenging, learners brains will become stimulated, releasing something called dopamine. Dopamine is referred to as the sweet-spot of learning. When a coach changes the variables/restrictions or adds constraints into a training, it forces players to come up with different solutions to be successful, this will lead new strategies and the development of new skills. There are many ways to challenge your players, creating various new environments for them to play in and learn. The following video offers just a couple simple ways to change a small-sided game.