Officers responded to the gym in the 3000-block of North Broadway at about 6:15 p.m. and spoke with a 28-year-old man who said he was sexually assaulted by a 35-year-old man who was still at the scene, police said.
The man was taken into custody and charges are pending, police said.
The victim was transported to Illinois Masonic Medical Center in good condition.
Area Three detectives are investigating.
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