I can't recommend yoga highly enough for these issues! I've been practicing yoga here in Belize for around a year now, and while I still have some hamstring tightness, I have gained an incredible amount of flexibility all over my body -- hips, shoulders, back, etc.. It helps with strength as well, not bulky strength, but long, lean muscles. If you look around an intermediate yoga practice, you'll see a lot of slender, toned bodies with excellent posture, a testament to the results of the regular practice of yoga.

There is a woman here in her early 70s who takes class with me, and she can totally whip my butt on all the poses. She's been practicing for around 7 years, and her flexibility and strength are equivalent to someone decades younger. She made me a believer! So, no, the problem is not "too many birthdays", the problem is lack of use & stretching. It's never too late to start.

Even if you don't care for the spiritual aspects of yoga, the body changes it will bring are undeniable. I'm 51 and a convert!