I’ve been doing CrossFit for 7 years and have never been able to do a pull-up. It wasn’t that I was completely incapable. I just blanketed my energy over all movements. It wasn’t until I dedicated 15 minutes a day, every day, for 30 days that I was able to do a pull-up. Why? Because I focused my effort.
It’s the same thing as watching my son with a magnify glass. Hanging the glass over a wide area distributes the light evenly but channeling it at an angle in a narrow, intensified effort produces fire.