During intense exercise, your muscles produce lactic acid, a byproduct of anaerobic metabolism. This acid buildup can create a burning sensation and contribute to muscle fatigue. male fitness pro should be performing an arm work-out, during mid-day, photography style, through the lens of a Sony α7 III camera, equipped with a 100mm lens set to a wide-open aperture of F 1.2. --ar 16:6 --v 6.0 --style raw