Kitten Stretches When Walking Towards Me?

I would like to know if it is normal. My 3 year old cat has been doing this for at least a couple of months now, and I have seen him do it with other cats too. His name is Cuddles.

My cat always stretches when he sees me come to the door or when I’m leaving the house, but sometimes only a leg will stretch out and not his whole body. He also does this after i’ve been gone from home all day long as well as every time we’re about to go somewhere new/different or whenever he sees strangers around our neighborhood (like people that may be potential predators). For how long has your cat done this? And does your cat ever do anything else besides stretching? If so please tell me what those things are! Thank you very much for any answers!