My morning commute was ruined by a quote that came from Texas head football coach Mack Brown. Sure, I don't think anyone has ever held Brown in high regard as a great thinker or scholar, but this is something he needs to get straight.
He mentioned in an interview that penalties “have been one of our Achilles' heels lately.”
OK, here's the deal. You can only have ONE Achilles' heel.
Back in mythology, Achilles was a great and seemingly invulnerable warrior because he had been dipped in the River Styx. But, he was held by his heel when he was dipped, so that spot would be his only weak point. The rest of him, immortal. The ONE heel, his ultimate downfall.
So, if you've got three or four areas on your team that are causing you to struggle or lose, you don't have three or four Achilles' heels.
If you're playing perfectly in all other phases, but you're being brought down by ONE aspect (i.e. penalties, turnovers, special teams, weak quarterback play from numerous 5-star recruits), THAT'S your ONE Achilles' heel.