My cat was spayed a week ago and we were directed to keep her away from other pets and reduce her activity for 2 weeks. She has done everything she can to continue playing with our new kitten but I've managed to keep them separated enough, and her stitches have healed nicely. Tonight she randomly and swiftly climbed up our window screen, perched on the curtain railing thing, cried for help getting down...as I held my arms up to her to guide her she took a sudden and overconfident leap at them, slamming her flank into my open palm. Her stitches are fine but I'm worried about internal damage. It's been 2 hours and she seems fine so far. My question is what are the chances that damage has been done?
The only right answer if you are concerned is to have a veterinarian examine her.
That being said, while she is still healing a week after surgery, in all likelihood she is fine. You said the external sutures are intact, which is important. The vet will have placed internal sutures where her ovaries and uterus were, and there is a small risk that excessive activity could loosen these sutures and cause internal bleeding. Such complications would be very uncommon a week after surgery.
I think it is a fair plan to monitor her closely over the next 24 hours, and if you notice any behaviour changes, pain, vomiting, decreased appetite, lethargy, or other abnormal changes then to take her into the vet immediately.