Mentzer is on the thumbnail but the video primarily features Mendenhall.
Matt Mendenhall came along in the 1980s and he was in the class of bodybuilders that were good enough to become a professional but never quite made it and they stand out for that reason. A few other people in that category would be Rory Leidelmeyer and Gunnar Rosbo. One of the things that stood out with Mendenhall was the calf bump and you see it in Pumping Iron on Schwarzenegger’s calf, like gnarly impressions in Gold’s Gym when he’s flexing his calf muscles. You also see it on Mike Mentzer, an actual bump sticking out of the lower part of the calf, and this is pre-synthol. It’s something that’s natural and more prominent on some people but nobody, but nobody, had this to degree that Mendenhall did. Mendenhall’s calves stood out so much because he had narrower ankles narrow knees which made his calves look all the bigger and when he would put one leg forward, tilt the ankle up, and flex the calf, he had a clear bump that was just unheard of, still is unheard of to this day, to that degree, although people like Phil Heath comes to mind as someone that has it. You can look at Anatomy pictures that show detailed drawings of calves and they do have all have that gnarly type of look that Schwarzenegger has when all the fat is stripped away and the more the calf is developed. The the leaner you are the more chance you’ll have that bump on the inner calf.