I can touch my toes but my dh cannot. Looking at him, it is not the length of his arms or legs. It is because his back cannot bend forward. If he is sitting on the floor with legs straight and extended, his back stays about 45 degrees to the horizontal however much he tries to force it down.
I can fold up like a suitcase closing and touch my knees with my nose. However, I cannot do the reverse bending backwards. I longed to be like a ballerina where the back bends backwards at the waist to 90% of the pelvis, like a dying swan. Looked so good. Nah, I'd have to break my back first.