There is another possible very cheap and simple solution: a long loop of cord or webbing with a tripod bolt set in it. Screw in bolt, put both feet through the loop, spread your legs and push the camera upwards to form a tight triangle of cord with the camera at the apex. If you get the length right (have adjustment!) then your camera and body are both held in position but can still follow action.
It does not work for all people or situations but always worth trying and keeping one in your bag ... very light and portable!