Hi, I'm not looking to beef up or anything, just improve my general physique and become more tone. At the moment I'm pretty skinny (BMI borderline healthy/underweight) and I haven't played tennis (or any sport) for 2 years which I'm planning to start again. Obviously I need to tone up if I am to stand any chance. My friend advised me to go the gym, but honestly is this really necessary in my situation? Can I just do morning runs, pushups, situps, squats, etc.? (basically stuff I can do at home because I am a poor uni student)