Alright, so lately I've wanted to get some more stamina. You know, being able to do activities for longer amounts of time without feeling the effects as much kind of thing. Last year I used to be able to play 3-4 sets of tennis without being too tired. But now I can only seem to play 1-2 and I'm quite tired, so I have began to take certain steps into increasing my stamina. I just want to know if I could be doing anything else. So far I have been going on runs every morning for between 30-45 minutes. This isn't a light jog or anything. I'll jog for a bit and then sprint for a bit, cycling between the two. Also, i've been doing pushups(50-100 a day), situps(100-200 a day), and jumping jacks(200-250 a day). I also will go for long bike rides 1-2 times a week. I can feel my body getting more used to my routine every day, but I was wondering if I could do any other excersizes without weights (since I'm to poor to be able to go to the gym). If anyone has any suggestions, I'd be glad to hear them.