17 year old friend of mine, African American descent; starting to work out a bit with weights, always active in basketball and football but never bulked up. Height, 5 10 weight, 140lbs. Just started noticing on his Right bicept horizontal striations on the distal bicept. There are three predominate lines across hi bicept when he flexes his muscle. Not as noticible when relaxed but can be felt under the skin. What would this be froma nd what could be done. No pain or swellins at this time, just three dents accross the bicept.