It depends on how much weight, and how they gain the weight, I agree, but 40 lbs
is a lot of weight. If you getting while growing 2 inches and your frame is filling out, its a lot different than putting on 40 lbs to a full grown person (Von Miller was not near as good after gaining 20 lbs a few years ago and losing weight helped him). Some people will continue to get faster as their frame fills out. Its finding those guys that are late bloomers in that way.