This Sunday’s AFC Championship game between the Denver Broncos and New England Patriots will feature starting quarterbacks with a combined age of 77 years (and a combined height of 12 feet and 9 inches, if strange mental pictures are your thing). 39-year-old Peyton Manning, winner of one Super Bowl, and 38-year-old Tom Brady, winner of four, will be facing off for the 17th time in their NFL careers. Not bad for a couple of geezers.

Despite suffering partially torn ligaments in his left foot this season, undergoing a cervical fusion in 2011, and enduring a lifetime of sacks (including a painful-looking blindside tackle late in the second quarter of last week’s game against the Steelers), Manning has hinted he wants to play next year. Meanwhile, Brady has come out and said he wants to play ten more seasons, and he may have actually been serious.

Longevity and success in sports are largely due to genetics and luck, as we all know. Both of these future hall-of-famers have the necessary height, lanky frames, strong arms, timing, and inherent football-vision to be top QBs. They also, no doubt, have the self-discipline and resilience to practice, stay in shape and rehab injuries, and persevere against obstacles.

“Self-discipline” and “resilience” sound like clichés. Of course successful athletes have discipline and resilience. Any sports fan can think of an athlete who had all the physical gifts and sports IQ to be a star but bombed because they didn’t work hard enough and failed to avoid distractions. Who doesn’t like a story about a high draft pick that turned out to be a bust? Well, unless it was your team that made the pick.

But anyway, we aren’t just throwing words around. Caliper has worked extensively with major professional sports teams to identify the attributes of successful athletes and advise them on draft choices, and our research has turned up the aforementioned “self-discipline” and “resilience” in top performers again and again. These qualities are derived from specific personality traits that are measurable, scientifically validated, and quantifiable (in terms of percentiles). These traits include ego-strength, which describes one’s capacity to rebound from setbacks; self-structure, which describes one’s motivation to make and follow through on plans and decisions; attention to detail for spotting and correcting errors along the way; and level-headedness to avoid letting one’s emotions take over.

Knowing this, you can look at star athletes and see why they excel against competitors who display the same physical gifts but, perhaps, lack the so-called intangibles to be champions. You may see discipline and resilience at work, too, in a manager you admire. Perhaps you possess such attributes yourself.

Peyton Manning might retire after this season and, if not, surely will after the next, and Tom Brady’s body is certainly not going to withstand the rigors of pro football until age 48. But, for elite athletes, there are worse things than spending your “twilight years” playing QB in an AFC Championship Game.