I'd strongly second resistance training, it doesn't really take that much time either.
A simple program like Starting Strength will have you train for not much more than 60 minutes three days a week and you'll make significant strength gains up to 1.5x body weight easily.
A simple program like Starting Strength will have you train for not much more than 60 minutes three days a week and you'll make significant strength gains up to 1.5x body weight easily.