To cut a muscle shirt, mark out lines to cut along the sleeve, around the collar and the bottom seam. Cut along the lines with scissors, and gently pull on the arms, collar and bottom to stretch the fabric and hide imperfections.Continue Reading
Use chalk or a pen to mark a line one inch away from each shoulder seam, collar seam and below the armpit seam.
Use scissors to cut from the marks at the armpit seams to the marks at the shoulder seams. Cut along the lines for the bottom seam and the collar seam.
Pull on the arms, collar, and bottom to stretch the fabric. This causes the fabric to curl up, hiding imperfections resulting from cutting the shirt.