I'm 64. I stretch more than doing specific core exercises. Although, I had an issue with sciatica and got physical therapy twice per week 9 months ago. They focused on core exerciss. I did those exercises at home for about 3 months. Now, I just do a couple of yoga stretches. I have aero bars so I'm in that position a lot. Then Posture 2. When I'm tired and on the way home, I'll be in Posture 3.