If a random DF board poster (admittedly, one who goes to a gym) can barely keep up at 20kph, I'd say 26kph is pretty darn acceptable top speed for a professional runner.
Maybe the gear I used to measure my speed is faulty. Or your assumption is faulty. I will admit that my gym is a bit shady and my dad's car is rather old. (This may cause a legal issue...)
20 KPH is a rather high speed. According to my treadmill at least... Hell even at 15KPH it's insanely fast. Faith, while being a trained runner, isn't running a sprint. Considering the stamina she seems to have, it would be expected she could run maybe a few kilometers under the conditions she exposes herself to. But as any trained runner would tell you, it's extremely stupid to run full speed while performing free running. Running on a 100 meter dash is nothing like free running or parkour.
Hell the world speed record for a 100 meter dash is 9.5 seconds. That's 36~ KPH.
Hold your stinkin' horses boy. Nobody can sustain such speed for more than a few seconds before practically fainting. We're talking about 100 meters here. Faith runs about a kilometer or two per level. She runs at 12 KPH. A trained runner can maintain 12 KPH for an hour or so before getting tired. Faith exerts a lot of effort. I consulted a recent Ph.D graduate that did a fair share of study on running as part of his Ph.D. Before you ask, the recent Ph.D is a friend of mine.
Go to any local gym. Ask any of the regular treadmill goers. They will mock at you for saying that 12 KPH is slow. It is a reasonable speed for running. Ask any true traceur you know. They will say the same.
20 KPH is about as fast as I can possibly run. It's about as fast as most people can run. Those "Trained runners" you see in the Olympics dedicated their lives to becoming that fast. But they can't maintain that speed for a very long time.
Faith is very nimble and athletic. But running at 26 KPH is humanly impossible under the conditions she's in. Vaulting over fences? Escaping cops? Sustaining impact over and over again? GETTING FILLED WITH BULLETS. (That's what she said joke cue.)
Not to mention the worst of all. The pressure.
A reasonable run speed for Faith would be 15 KPH. 12 is the normal run speed. Faith is a highly trained runner. We can assume some handwaving since the game is set in the future. Hell maybe Faith is on drugs. But we can't just assume that. The game has to say that. Referring back to the lolwhut storyline.