Just thought I'd drop in and provide a little information on the type of workout they were doing. Forgive me if this is all a bit vague and jumbled, but it's been a while since I've done anything with S&C and am typing this on the quick. It's called a metabolic circuit. Google "metabolic circuit huskers" and the first result will be a pdf that explains it in pretty good depth, with a full breakdown of the lifts and work:rest ratios. It was developed and used by Nebraska in I believe the 90s, and continues to be the foundational program used by coaches belonging to the Epley/Arthur coaching tree. It is the "strength" component in a split program, which I'd wager coach Duval is using and looks essentially like this ("Heavy" and "Light" just means % of 1Rm used for weight):
Monday Light "Power" (e.g. Clean shrugs, Hang Clean; plyometrics and speed work on the field)
Tuesday Heavy "Strength" (e.g Metabolic circuit; agility on the field)
Wednesday Off
Thursday Heavy "Power"
Friday Light "Strength"
It is a KILLER workout. The intensity of the lifts combined with the W:R ratio makes you feel like you are going to die. The closest thing I could compare it to is like the feeling after running a really hard 400 or 800 when you're not properly conditioned, only worse, for about 35 minutes. If you are in less than excellent shape you will not be able to complete it. Even guys who are in "good" shape will really struggle with it because of the unique and particular stress it imposes on the body. I believe at one point they wouldn't allow athletes to do it without first being in the S&C program for two years, and even after that they had to do a month's worth of preparatory workouts which were basically metabolic circuits-lite (2x10 vs 3x10, working at lower %1RM).
With all that said it will get results. It's almost like a cheat code for really jump starting physical development. Also, while it is akin to physical and psychological torture initially, you adapt to it pretty quick. I believe coach Duval said something to the effect that guys would be in survival mode at first, then later being able to really grab the reins and push it. That's a pretty accurate description of what the athletes will experience