The only one is know of is the one that Urlacher trained at. I believe it’s called Competitive Edge or something to that effect. If I remember correctly they are really into sports specific training, especially performing drills with bungees attached. Seems a lot like SPARQ.
Yet again, when will we see athletes get smart and go train with a Charlie, Dan Pfaff, etc. for the combine/pro day?
Probably when their agents tell them to 
I own their book…basically a bunch of bungee resisted drills (also on 45 degrees runs…do not think the resistance is specific to anything…) no periodized weight training, almost identicla for all position…only interesting topic covered was pool training…
chip smith use resistance for everything possible, his claim to fame was brian urlacher.
Rivers ran the 40 in what is being reported as under 4.55 seconds with at least one team stopping the clock in as low as 4.51 seconds. Just for good measure Rivers posted an off the charts 42.5 inch vertical leap. RB Chauncey Washington also had a good day after he reportedly ran in the 4.35 range for the 40.
Funny thing is that neither looked very good while doing it, very long GCT for both. It’s on NFL.com
Washington is thick…
Grass = slower GCT.
Very true, especially FieldTurf, which in my opinion is very spongy feeling opposed to an immaculate grass field which feels pretty fast IMO
my bad, i thought that field was natural grass.