I still remember fifty five years ago when members of the local high school football team, and after graduation, were drafted and rejected by the military due to football injuries.
Meanwhile, the rest of us, who did not play football, ended up in SE Asia.
In a similar vein, the military docs started doing leg circumference measurements above the knee because knee injuries, repaired or not, quite often led to some atrophy in the upper leg muscle. This could indicate a potential for injury that wouldn't otherwise exist. I'm not aware of any washed out due to that but know that there was careful scrutiny.
“I still remember fifty five years ago when members of the local high school football team, and after graduation, were drafted and rejected by the military due to football injuries!”
I had two cousins, in my age group, who flunked their physicals and missed Nam. They could barely walk without pain at age 60, and they have gotten worse. Mentally, no problem, and both got Phd’s in tough fields.
Several friends, who played highschool and/or college ball had the same outcome.
One friend played in the Rose Bowl in 1941 with those funky helmets, 4 years of high school and 4 years of college football as a running back and linebacker. Joined the Army and got in the Army Air Force and became a General in the AF reserve later in his life. He had a few limps and gimps, and his mind was as sharp as a tack until he died in his 90’s. His brother played the same years of football and was mentally there until he died in his 90’s.