Question: How can I gain muscle mass?

Hi I'm a white kid who is flexible athletic and durable. There is only one problem, I can't gain good muscle mass! I workout 3-4 days a week. Are there any leg work outs that really stand out because I do gymnastics and karate and I need a strong base. Info

5ft 4

102 lbs

14 years old







http://ift.tt/1yPIgoz

via Smart Health Shop Forum http://ift.tt/1yWMu2s