I would not totally dismiss the altitude issue. My first duty station was Ft Carson and it took several months to acclimate to the altitude. Full exertion is unaffected initially but the longer the exertion is repeated your muscles don’t respond as quickly. The Huskers should have rotated players often and put them on oxygen on the sidelines.That's just off season talk, pretty standard. Try not to buy into it.
The problem at NU is that those stories about the "improved" S&C is written about and regurgitated by two large in state news papers, a magazine dedicated to the team, several beat writers for multiple recruiting websites, and several dedicated radio programs. Every story is blown up, so the hype train gets going on a pretty insane way.
in the second half, there were many more missed tackles and yards after contact. They could have been sucking for oxygen they could not get their shoulders into the ball carrier- wound up reaching for arm tackles.
Even with the altitude, the second half had less energy, bad tackling, weak play calling, safeties missing deep coverages, and a missed field goal. Colorado had the mojo in the second half and just outplayed us.
I think we will see these problems many more times this against Wisconsin, Ohio State and Iowa. I can’t see us taking the Big 10 West now.