(1) I know that in the year that Bolt broke the 100m WR the first time, he said that he lifted weights in the offseason.
(2) I know that Bolt has talked about the 10+12 rep thing that some here have wanted to laugh at. But what hasn’t been mentioned is that Bolt talked about the weights helping strength endurance. There hasn’t been talk from Bolt or Mills about big weight numbers or explosive bursts from blocks. Bolt, in fact, talks about him not being like smaller, more muscular sprinters almost derisively. The weights being used in the Mills camp seem to serve different purposes, and John Smith is somewhat like that with the higher rep work than the lifters here seem to favor.
(3) Remember that the big category here is strength training, not just weight training. We know that Mills and Francis use sleds; We also know that Francis goes up to 50 pounds on sleds and also uses steep hills, as well as accels out of blocks on grass. If you don’t do some of the non-weight strength work, then you probably need more emphais in the gym.
In “you emphasize weights specifically” I’m really talking about a concentrated period in Verkhoshansky terminology, where you are empasizing strength gains in the gym, and remember that Charlie has this in the early phase of his GPP. Mike Young has made the point that you have to be “strong enough,” but just strong enough as emphasis on high strength numbers that diverts resources from track training can be detrimental. But if you are NOT “strong enough”, you might need to emphasize strength (and less sprinting) for a while, because combination makes it difficult to make major strength gains.