Just as an example, there were evidently reports during the 2007 Glasgow airport attack that someone attempting to subdue the assailant and assist police kicked said attacker in the testicles… but somehow managed to do so hard enough to injure one of their own foot tendons.
the messed up thing about getting old is that you can start hurting yourself doing things that used to be “easy”. like lifting heavy weight or gripping something tight (like opening a jar). all of a sudden it feels like your muscles are breaking your joints and damaging your tendons/ligaments. its the muscle memory that gets you into trouble. good times, good times.