What are some good drills to have more stanima when catching.?

so i used to catch in little league but i ploayed football so it didnt really put strss on my legs. but now im on an AAU team and not playing football so its really stressful on my upper legs. i was thing i should just sit in the catching position for a lengthy time. but what do you guys think. my grandpa was a professional catcher so i have hopes i can be pretty good at it too. i know its not a gurantee though