Strength training for the Youth GK (ages 12-14)

I like to implement some type of strength training with my youth #gk program mainly using body weight and max a 10lb medicine ball.
Here, while holding the med ball I only have them do 1 set of 8 reps. squats, squat-press, shoulders & side lunges.
Then I go into 2 sets of 5 plyo box jumps 20 inches .
To help get the legs movin I have them perform lateral movement and finally just a quick handling circuit (end of video) catching the med ball while doing some mobility over steps , footwork over poles, etc
What are your thoughts on youth Goalkeeping doing strength Training every so often? Remember these GKs are ages 12-14., hope to hear from you!!
#GK4LIFE ...

Session on 10/8
Session focus was on Ball handling (Activation) Followed by reaction training using the ProDeflect, where the keeper must make three basic saves + a reaction from the shot from about 12 yards with the possibility of the ball deflecting through the frame. The other progression had to keep her working on a blind cut back cross followed by a ball simulating a header reaction with the keeper having to Open the hips reacting to the ball and at the same time using their communication as they would in a game.
Got some of my activation progression ideas from
NC courage GK coach Nathan Thackeray ...