Back in the day when I went through basic we had to do out PT test run in boots. That was a stupid requirement.
Lots of foot and shin problems amongst the troops.
A big difference between running a mile, two, or three compared to 10, 20, or 30 yards when someone is trying to shoot you.
Boots and war belt for us! For those not military, war belt is webbing with a canteen and also a first aid kit, all else stripped off for the run. Weight is a thing!