The Glory and Beauty.

Proverbs 20:29 "The glory of young men is their strength: and the beauty of old men is the gray head"

Strength has a lot of meaning, literally, as a young man, they can do what the old man can’t do because of this strength, vigourgeous, energetic, some young turn their face to worldly things, that’s why the Teacher remind them to remember God "Remember your Creator in the days of your youth, before the days of trouble come and the years approach when you will say, “I find no pleasure in them” before the sun and the light and the moon and the stars grow dark, and the clouds return after the rain; when the keepers of the house tremble, and the strong men stoop, when the grinders cease because they are few, and those looking through the windows grow dim; when the doors to the street are closed and the sound of grinding fades; when men rise up at the sound of birds, but all their songs grow faint; when men are afraid of heights and of dangers in the streets; when the almond tree blossoms and the grasshopper drags himself along and desire no longer is stirred. Then man goes to his eternal home and mourners go about the streets. Remember him before the silver cord is severed, or the golden bowl is broken; before the pitcher is shattered at the spring, or the wheel broken at the well, and the dust returns to the ground it came from, and the spirit returns to God who gave it". (Ec 12:1-7).  Men lose their ability to perform, and the driving desire to perform some physical activity, their glory faded.

However, old men begin acquiring something in their 30’s that young men can hardly understand "wisdom". It is a combination of mental and emotional maturity, experience, and accumulated instruction. Though declining in strength and stamina, older men grow in knowledge and understanding until the very late years of life and it will see in their gray hair "a Crown of Glory"