Holding on to something is guided by a strong reflex. We tend to use too much effort. From early childhood, we make the experience that holding on too little has negative consequences (we drop the glass of orange juice), while holding on too strong seems to be just fine. This tension tends to build up - not only in our hands, but also the wrists and the musculature of the whole arm. (You probably made that experience in the lesson about "soft hands").

Try for youself how much effort you need to actually lift a glass, hold a pen or press down a doorknob. The optimal effort would be just enough not to loose your grip.

Try making this in everyday life, whenever you lift or handle an object to form a new habit in working with your child.

Whenever I can, I work from below - "giving support" instead of "lifting up".