Do you have tight hamstrings? You aren't alone. In fact, just a few years ago I could barely reach down and touch my knees! Sitting around in a cubicle, then the car, then watching TV definitely didn't help.
And my tight hamstrings effected my golf game, specifically my posture. If I were to take a look at my setup a couple years ago, you will notice that I was very much bent at the knees. This was because my hamstrings were too tight, and I could not actually lengthen them to get into a taller posture. It also prevents a player from being able to get the appropriate hip-hinge at address and maintain it throughout the swing.
This also plays a major factor in using ground force throughout the swing, and being able to get through the impact position in a strong post position.
If you can't touch your toes then this is a major indicator that you'll have some of the same issues in your golf posture and swing. But, we don't want to just try to touch our toes...