People who are not physically fit (tennis elbow) shouldn't even be in the team, but, of course, continue to be ad infinitum. So thanks a lot for these small mercies like declining the captaincy. And when you do make up your mind about retiring, try convincing the other physically unfit oldie Sourav Ganguly as well. He drops too many catches, scores too few runs, and consumes a large number of balls.
