Indiana's old S&C staff that Saban stole to Bama a few years ago, designed individual plans for each athlete that focused specifically on identified "weaknesses". As an example, they were actually able to get the players a measurable increase in their actual MPH top end speed...Saban saw this and they all came to Bama. (Top running speed increased on average 3 mph). Articles below get into what they did. Unsure if Duval did any of this.With respect to S&C different player positions need to be trained differently. Also each individual player's needs vary somewhat. Stretching and strengthening go together and training the whole body as a unit. Some will argue against stretching for building strength but that has to do with timing and the amount done and duration in relation to times. People recover somewhat differently. There's got to be some tailoring going on for each person. A lineman trains differently than a receiver, etc. Speed, power, agility and a number of things to consider.
It's hard to say what has been going on or not going on. Perhaps the attention to detail wasn't what it needed to be. Strangely enough, one's breathing habits can play a significant role restricting playing at a higher level. Things being marginally different can have a considerable effect. I don't know...To me Scott appeared and acted tired much of the time. Lack of sleep and other possible considerations really does affect one's ability to function at a high level. It's a demanding profession.
https://www.indystar.com/story/sports/college/indiana/2018/02/15/new-iu-athletic-performance-coaches-mix-cutting-edge-technology-familiar-lifts/336842002/
https://www.stack.com/a/how-a-unique-speed-training-program-changed-indiana-football/