I’m happy to read a study that has real data, but any conclusions we draw from things like this has to also explain the fact that in a vast array of areas where we have access to objective metrics like strength, speed, and general athleticism, records are set most years and there’s no sign of a “dead ball” era in sports across the board. This includes sports where people are heavily tested. Cycling is maybe the one example, but that’s probably as much the absence of doping (or less effective doping) as it is a diminishing innate biological capability.