Just imagining the physique of an elf who’s lived a couple thousand years of running up and down literal trees, fighting and clambering around… that’s got to be quite something.
The tallness, corded muscles stretched across long bones, someone who looks lanky only because he’s so tall, but taken altogether, Legolas would be terribly strong and frightfully capable.
“Tall as a young tree” signifies uncommon height.
Tolkien explicitly states that he is “immensely strong” and could “draw a great war-bow with ease” and we may assume speed.
This guy would be such a mind-bender to try and figure out, because at first glance you might think he’s just a tall, lean dude. He’s a fair elf, and maybe he looks a little dainty at the first glance. But the proportions just serve an illusion. He’s big, but he’s also very fast. But not only is he fast, he is very strong. Faster than such a big guy should be. He’s not a broad tank of a being, he doesn’t have the powerful and broad dimensions of a hefty strongman or a stout and strong dwarf, but he is strong enough to do demanding tasks that require great strength at startling speeds with that deceptive physique.
He’s too big, he shouldn’t be able to move that fast, no man could ever be that big and move that fast… but also, you can’t hear him either! He should be clomping around like a horse with all those bones and muscles to haul around, but he’s light-footed and you would never hear him coming. In order to be that strong, he’s got to be heavy right? It’s got to slow him down, right? Except it doesn’t. It’s like none of it weighs him down at all.
You don’t really realize the dimensions of this guy and how scary he could actually be until you get real close. And then you realize he’s huge. He’s tall. He’s got muscles that work to make all the insane things he does look easy. He walks like none of this weighs him to the ground at all. His bow would humble the greatest bowman among humanity, and he makes it look like child’s play to draw over and over again. There’s such presence to him that you should at least be able to hear him coming, because you’d hear any man that tall and strong coming towards you. But you don’t.
He should be scary, with all these things added up…
But he smiles and laughs easily, he sings to himself as he does things, he talks to kings and lords and peasants and children all the same. He acts like a Most Normal Guy, except he’s generally quite cheerful as well in the middle of terrible happenings.
And then you learn his father is a king. The last Elvenking left in this world. He is his son and heir.
And you would never know, because he never says it for himself.
You only learn because someone else says it out loud.
“Oh yes! That’s Legolas of the Woodland Realm, one of the Fellowship of the Ring, son of the last Elvenking!”
This towering, uncanny, fair creature is one of the most powerful people in Middle Earth, and you would never know beyond the hint of his physical strength and presence. His focus is not on himself, always reaching outward to his friends. He is not prideful in his own power, but concerned with the people around him.
Looking only at him, you would be charmed and unnerved in tandem, because he is so very tall and strongly-built, and also humbly pleasant and cheery.