The Bulgarians had a tradition of awarding quite generic Medals for sporting events, even major national and international events. In the early years of the communist rule this tradition slowly faded away for the generic Medals to be replaced by specific or "cover all" Badges.
This first Medal "For Participation" is for the 1948 Sofia Republic Autumn Horse Racing Horse Race of the National Union For Sport And Technology. These will have been created and awarded in a bespoke and extremely limited number.
Here is a Medal "3rd Place Weightlifting Plovdiv". Although it is undated it is more likely from the late 1940's than during the Tsardom. The "weightlifter" is very similar to the "worker" on the "National Order Of Labour" founded in 1945.
Here is a different "3rd Place Central Soviet Voluntary Sport Organisation "Red Banner" Women's (Skiing) Borovets 1951". For different skiing types as depicted on the fronts.