One problem for many beginners is strumming with a rhythmic flow. The wrist becomes rigid and the forearm moves to much to compensate. Keep your picking hand in a constant down up motion even when you aren't actually striking the strings. Follow the down up strokes and counting in exercise 1 closely before playing exercise 2.
Ex 1
Exercise 2 has the same strum pattern and count as exercise 1 but includes some rhythmic variation.
Ex 2
Exercise 3 has a typical triplet stum pattern and count. The problem with this pattern is the stiff wrist movement that it causes.
Exercise 4 corrects this problem by again using constant down up strums. Play through the exercise slowly to develop your wrist movement.
Ex 3
