i think ankle weights are to hard on the joints, maybe basketball but not badminton, if u want to gain stamina use a skiping rope, plyometrics(with or without weight) and jogging alot. as for upper body, just dont use the backpack thats hard on the back, how can u do that? but just work with free wieghts with upper body, as free weights are better then machines, just be carefull, and this isent body building, you want to be able to move quickly, not like a tank, so tone ur muscle dont build them.
go climb a hill everyday, u will have tremendous stamina. i used to hike a lot and when i jog or play badminton i feel that i have endless stamina even though i used to run around the court ineffectively.
run stairs on a regular basis... i run up stairs whenever i'm given the chance. i have to go up 4 floors to get out of the underground subway train station, so i run the stairs all the time, usually with my badminton bag on my back too. then where i am at school, theres lots of stairs where stands are for sporting events in the indoor arena, so i run the stairs there too, regularly.
I suppose it helps with your aerobic exercise regime but you will be putting extra strain on your knees.
don't you think it will exert too much stress on shoulders? might not be a good idea to play badminton with backpack....just imagine yourself jump
I would suggest working out your legs more often, increasing your cardio, or even putting on ankle weights when you are practicing or doing drills.
