I have a trainer this winter that measures watts, but, last riding season I had a Polar HRM, and no way of knowing watt output for recorded rides. All I have is the calories used, time, dist, HR, ect. I have found the formula to convert watts to KCalorie, but not KCalorie to watts. Is it possible ? I would like to have some idea of power output from this past season, to get an idea of where to improve next.