How strong are kids really?

Most kids I know that are seven and up seem to act very strong. How effective would a rear neck chokehold be from a seven-year-old to the average adult? Would they be able to punch/kick and successfully defend? From what I know kids these ages are very strong, how strong are they really? Is it really true that an adult can stop a seven-year-old hardest punch while picking up the child with a single hand? How is this given in they are going through absolute Hardest? I thought kids this age were strong?