I have done a whole heap of exercise in my life time. I started with team sports at school (loathed it!) then into my 20s and 30s I was a gym bunny on and off and latterly it’s just Yoga, Yoga and more Yoga.
An intrinsic part of exercise is stretching muscles effectively so you can keep your muscles long lean and knot free.
The mechanics of effective stretching for me is focused on the ligaments and tendons that join muscles to bones. I am not going to blind you with anatomical science but wholesome stretching doesn't just involve just stretching your muscles any which way, but mindfully done, you can release a whole lot more than just tightness in the body.
I am a total convert that our emotions create a storehouse of stuff in our body and our breathing can hold a major key in the deep release and subsequent ease of our body/mind; our exhale breath specifically.
The exhale breathe is simply a breath of surrender, a letting go and during stretching if you exhale your body/mind can release the past at astoundingly deep levels. Unconscious tension always resides in the body on one level or other, so stretching takes our attention to what is tight and the tightness is often a sign we are holding mental/emotional tension.
Next time you hit your mat try the following:
Stop, be still
Draw your attention into your body
Take your time!
Get into a Yoga posture where stretching is required
Take yourself to a comfortable limit where you feel the challenge in the muscles as they stretch
Take at least 5-10 breaths where you focus solely on the exhale breath
During each exhale, see if you can just surrender. Close your eyes and take your attention into your muscles. Release the tightness, let go whatever thoughts/feelings come up, give up trying to push yourself.