What Likely Caused The Striae On This Young Athlete’s Thighs, And How Should His Workout Routine Be Modified To Prevent Them?

a young man appears for a routine physical examination before participating in his high school athletics program. A cursory examination shows striae on his thighs, which are much larger than his calves and arm muscles. what has caused the striae, and what you suggest as a modification of his workout routine?