Until about four years ago I never had many striations on my chest.
Then I read about fascial stretching and posing after each set, and I started incorporating this technique. After every set of presses, grab a pair of light dumbbells and get into the bottom position of a dumbbell flye on a flat or incline bench. Hold for 10 seconds, trying to go lower on every rep.
This stretches the pecs tremendously. When you’re finished with the stretch, get up and flex your pecs into a most-muscular pose. The pump is unbelievable. Four years of using this technique have given me all the veins and striations in my chest that I could ever want.
‘Ron Harris, IRONMAN’s Ultimate Bodybuilding Encyclopedia