I have 2 boys. I wasn't very physical as a girl myself. Liked drawing & colouring in, reading, chatting with friends at playtime at school. I was convinced that whatever sex child I had that they would "take after me" with regards to Their interests. I disagreed with the "boys do play fighting" and said I wouldn't have toy guns and swords in the house. Ha. (They seemed drawn to them when I let them have free reign to choose eg a fairground prize) I didn't discourage them from choosing that and wouldn't have discouraged a girl either. I'm all about letting them develop their own interests but after making sure I expose them to what society views as "gender specific" toys and Interests too.
None of them showed ANY interest in colouring in or drawing or any craft beyond play dough really. I really did try. they would say "I've finished now, mummy" after 10 mins, "can I go into the garden and play football?" Leaving me to finish off their drawing! Now they are older the only drawing they do is cartoons where characters fight with each other or have special powers. Or they design a set of top trumps style cards with aliens or monsters.
They have both enjoyed gender-neutral (in my opinion) toys as toddlers such as toy vacuum cleaners and toy kitchen as well as "stereotypical boys toys" like cars and trains (trains were massive in our house). I bought them a baby doll but interest lasted 5 mins - mainly they wondered how it worked (it cried when you pressed a button etc) - showed now interest in play acting with it despite me pretending to comfort it etc and just threw it in a wardrobe so they didn't have to hear it.
There hasn't been any social conditioning in our house. There really hasn't. It pissed me off royally when a great aunt bought DS2 a blow up punch bag, telling me "boys love that type of thing". He wasn't that bothered by it actually so I gave it away.
However...They just can't sit still or quiet for long without an "aim" in mind. Eh ds1 likes Lego and will spend hours on building an item. But it's so that he and DS2 can play with it racing them against each other or bashing them together to see which one lasts longest. Not much imaginary play with them AT ALL (they did that a lot with Thomas trains when much younger though).
I think people that recognise a difference generally between how girls and boys play (therr are obviously some individual differences) are talking about a specific age group. Say, 7-11.
After that the physical thing seems to still be there (they jump on each other all the time and are quite touchy feely if they aren't pretending to scrap with each other and jumping on each others' backs as they walk around at break time) - an eye opener for me when I started working in a boys' secondary). But from my casual observation they start to get physically lazy unless they're stand-out great at sport and then they become gaming couch potatoes, a lot of them. But 7-11. I would say, yes, puppies.
With my two, (12 and 9) - leave them in a room seemingly occupied in something calm. You will come back 20 mins later and find them literally rolling round on the floor wrestling . Every time.
There is something in it. You can try and deny it, like I did. But there is.