It’s not hard to see why he won the gold medal at the 1920 Olympic Games, likely around the same time this picture was taken.
Note the cannon on the wall behind him. Yes, it was used specifically for lifting purposes.
In 1925, Cadine performed a one-arm swing with 90 kilos which was actually greater than his own bodyweight. Cadine could also right hand snatch 211 pounds and one-hand deadlifted the famous Apollon Wheels.
Also of note is the sand-pit floor — you’ll see this feature a lot in old school physical culture gyms as it made it so globe barbells and dumbbells were not damaged if they were ever dropped.