I'm a terrible runner endurance-wise, I can go maybe 3 miles and that'll do me just fine for any jog. Speed-wise? Ahhh..... no so much. Faster than a few, slower than a few. Sometimes I felt like I played sports in high school in spite of, rather than because of, any running proclivities.
However, my dad ran track in high school and he was always running when I was a kid. I remember when I was little and my mom worked during the weekend, he'd take me to the local high school track and he'd run laps and play with me on the football field... letting me 'outrun him' while I carried a football almost half my size down the field. Sometimes he'd want me to run a lap with him as he slowed enough to allow me to keep up (which, in retrospect, must've resulted in a semi-fast walk for him, actually). I'd always tried to get past him running fast down the long stretching straight-aways. It was at this point, my dad - whether he knew it or not - gave me apice of advice that in many ways has helped shape much of my attitude towards work and competing in general.
It's funny when you're grown up what you remember in moments as a young kids in retrospect. I cannot remember a single conversation word for word except one sentence which my dad told me in an almost off-hand way: "When you're racing around the track, do your best on the corners, look to pass others there, because everyone tries to pass each other on the straightaways..."; meaning, go your fastest, focus on passing at that point, bear down just as much then. He said his track coach always told him that in was in the corners that a race can be won (or lost, I see now). Everyone focuses and bears down on the straight-aways; the corners can be mistaken for places to 'get by' on the way to the straight away.
Now, I have no idea as far as track & field whether this is true, false, or just made-up. But it sure-as-shootin' seems to me this is dead-on for competing. In track and in all-else. The corners are your moment for differentiation.
Think of your job requirements as your straight away; you know what you have to do and you go out there and do it. It's not always easy and not everyone does it, but most can and do walk the line they see in front of them. Then there are the corners; the moments when others may rest, or may get distracted, or, even, may simply say to themselves & others, "That's not my job, I don't have to do that...". And, of course they are right. But those are the corners, and believe it or not, the corners can be the easiest place in the world. Where you may find others trying to just get to the next straight-away (job requirements), you will will be proving yourself invaluable to your team (company).
And, you know what else? Your company, or even another company, will end up seeing that there are others who can do what you do and you should be ahead of them, because you can do more. Then... you've won the race. Wash, rinse and repeat.
(Oh, and by the way, still push yourself during the straight-aways)