Here is a photo I took of my grandson in May while we were at my granddaughter's indoor soccer game. ISO 6400. Tamron 70-200 f2.8 and my K3. A little noise reduction applied. Forgive the arm movement. I call the little guy "The Blur" as he is a perpetual motion machine. The only way to solve the blur problem is to use an industrial grade strobe light at 1/1,000,000 second flash duration.
My K3 has been almost flawless. In Yellowstone this past June, for some reason, the shots started exhibiting weird colors. A reset to default solved the problem. First and only problem I have ever had in over on year of ownership. It is a great camera.