Create a highly photorealistic fitness portrait of a young athletic man performing standing barbell curls inside a modern professional gym. He should be captured midway through a controlled repetition, holding the barbell with both hands while keeping his elbows close to his torso. He wears a fitted black sleeveless workout shirt, dark athletic shorts, and training shoes. His physique should look naturally muscular, with visible definition across his biceps, forearms, shoulders, and upper chest, but avoid exaggerated bodybuilding proportions. Position the camera slightly in front of him at chest height so his face and upper body remain prominent. His face must be completely visible, sharply focused, and evenly illuminated with soft frontal fill lighting. Give him a concentrated expression with a subtle sense of determination. The background should include a dumbbell rack, weight plates, benches, cable machines, mirrors, and realistic gym flooring, softly blurred for depth. Add a natural post-workout sheen to his skin and subtle perspiration around his forehead and arms. Ensure anatomically correct hands, fingers, wrists, elbows, and muscle structure. Use realistic skin pores, detailed hair, authentic fabric texture, natural shadows, cinematic depth of field, realistic color grading, and premium sports photography aesthetics. The final image should look like a genuine professional fitness campaign photograph rather than CGI.