I’m an athlete (I’m a skate) … I’m 5’2 and about 103-105 pounds … I also stick to a good diet… But anyways I use to do TONS of cardio… Which made me lose a lot of weight…? But it wasn’t healthy at ALL. I’ve started lightly using dumbbells for my arms and the weight machines at the gym. Starting doing interval cardio no more than 30 mins and I do plymetrics… (We do jump boxes, ladders walking lunges; different squats jump ups burpees, sprints, etc) I know a lot of that is cardio but my teacher said I will be building muscle? How am I building the lean muscle of I’m not using weights? Thank you