The EIC matchs we shot a couple months ago had us running over 100 M for several of the different shoots. One had us climbing stairs to take positions in a window shooting down into a depression at targets at unknown ranges. I completely blew that one, but I think the biggest problem was shooting at targets at unknown ranges and elevations.
The Patton match was a sprint (200 M I think) followed by a pistol shoot, but we had time to catch our breath after the sprint, so the bigger issue was general physical condition than stressed shooting. By that I mean being in good shape allows your heart rate to return to a normal number in a few minutes after the sprint, which is a different issue than training to shoot while your heart rate is high. The first you can train for at the gym, but shooting with a high heart rate needs to be trained for at a range.
Most shooters without real training have a Bunker hill mentality and envision any action they might see as being where they will hunker down behind cover and take slow aimed shots at an adversary approaching over open ground. They don't have any idea of the elements of manuever and tactical movement that are required to be effective as part of a team or small unit.
Some readers here agree with what I'm saying and see the sense in it.
There is also a sizable percentage of the members here who have no idea about the requirements to be effective in a fluid battlefield. The percentage that doesn't have the physical abilities is even larger, and the percentage that doesn't have the training is even larger than that.
There are some guys that have the knowledge but not the physical abilities. Mostly that's because they got injured, old, or fat. That's life. Do the best you can to get in the best shape you can.
There are some guys that have the athletic abilities but not the knowledge. Find one of the guys described above and train.
Then there are the guys that are content "knowing" that they'll never have to take a shot at another human being, or if they ever do it will be zombie hordes that can be picked off at long range until you run out of ammo, and anyone who prepares by tactival shooting is unrealistic.