Here is an example of a leg circuit that I use with hockey players. I learned about the leg circuit years ago from Vern Gambetta videos and from Mike Boyle. It is still a great tool for us today. I really like it because it really focuses on developing leg power, strength, and endurance- both bilaterally and unilaterally. It serves as a good transition from or conventional strength and power work to more circuit based work.
What I also like about the leg circuit is that it is a great tool for youth players. When I begin working with a youth team or individual, we will start with the leg circuit. I am always coaching proper form and technique with each aspect of the circuit.
When we have the ability to perform the leg circuit properly with body weight, we will then add resistance. We will progress to a weight vest or dumbbells and then progressd to a bar with added weight as necessary.