This quick point is related to T0ddday's post about dads, stereotypes, culture etc..
If we are subjected to those stereotypes as we grow up, there's a good chance we will believe them. And by simply believing them, it goes from being a stereotype to a "physical barrier" in our brains. I think our brains are full of those barriers, in all kinds of different forms - not just athletics. So if all of a sudden we want to "defy our genetics", which might actually just be - realize our true genetic potential, we have to destroy such barriers in our brains as we attempt to progress. I've been guilty of it myself by saying "defying my genetics". I try not to mention "whiteness" as being a limitation, though it is somewhat implied when I say defying my genetics. As a coach, I would make sure not to use such stereotypes in front of kids/athletes, and also make sure to call out athletes or their parents for using these stereotypes etc.
TLDR: stereotypes become physical barriers in our brains if we end up believing them. I'm not a neuroscientist, but I imagine an "inefficient series of dendrites" and such that weaken the "go get it" signal.
As for myself, I often think about my brain being a limiting factor: especially for running. For jumping/sprinting, I often tell my brain to "let go" and "give me more". Maybe i'm just nuts, but I really feel like my brain holds me back more than my muscle/tendon physiology. One reason I think this is, when i'm feeling REALLY GOOD MENTALLY, I can get much more out of my jump/sprint/run sessions. If I let any self doubt creep in, the quality of jumps/sprints/runs decrease dramatically (sprints less so, jumps/running more so). So I kind of feel like i'm in a battle with not only the physiological factors related to muscle/tendon/nervous system, but also with my brain. I feel like there's things in there "blocking me" from turning it up a notch ... perhaps protective mechanisms given my current fitness/strength etc. I mentioned a "governor device for engines" in a previous post... that's kind of what it feels like.. how to remove the governor and inject the NOS??? 
I'm finding that more and more difficult with my own kids. I had never really thought about the impact of stereotypes because I try not to use them but when your kids ask you a question related to it you really have to think and be careful about not giving the easy answer. Also, it's very hard to control what teachers, coaches and other students and parents are saying because that's where a lot of stereotypes can stem from. Nearly all of it unintentional too.
Yeah I mean this is a really complicated issue especially when dealing w kids. It's basically that we have to balance three things - barriers, stereotypes and realistic expectations/limits.
I think the barriers that Andrew talks about are totally real and their is a bunch evidence to support how damaging they are... Just think about Roger Bannister and the four minute mile. Before he ran it people just were so sure it couldn't be done... Then he went out and did it only training 3 hrs a week (he had limited time due to his schedule as a medical student and only did 400m speed repeats on his lunch break)... Within 10 years highschool kids had done it and somebody had run a sub 8 minute 2 mile! He broke through the barrier for everyone and then it no longer had power over people and now it's not looked at as an amazing thing at all! These barriers really hold us back from make individual progress or progress as a society or human race! I hate when people have political ideas and people say things like "well a world without war is unrealistic cause humans are naturally violent war loving creatures"... It's like yeah maybe... But for sure if you keep saying that!!!
As far as stereotypes about race go they are mostly harmful if they involve any trainable quality... There are a fun non harmful ones - over here we have a stereotype that Samoan people are generally really nice guys. I don't see much harm in that - people expecting others to be nice is a good thing (we are far too fearful of others due to shows like CSI that make people think the world is full of psychotic killers) and if Samoans are effected by the stereotype and be nice rather than mean - well I don't really see much harm in that! What's important to realize is that stereotypes can be harmful without being explicitly negative. People don't see the harm in the stereotype that black people run faster or Asians or good at math cause they don't understand how it effects others. It's harmful for members of the race that the stereotype is about because of the pressure it puts on them. In the case of math - the stories about Asian students committing suicide at MiT because of the immense pressure is an obvious reason why it is bad. Or the fact that a black athlete who isn't fast will get branded as a lazy person who won't work hard while a semi fast white athlete gets praised as being extremely hard working! That's wrong and damaging to everyone! And then of course there is the contradiction that people are using empirical data as justification for believing some positive things like being good at math or running fast but claiming to not believe it at all for negative things. I am always like "wait you think it's completely clear that whites are slow and blacks are fast cause a black guy won the 100m but you don't think poor test scores indicate that black people are not as smart?" Hmm.. I don't believe you, I think you think there is truth to both but you just don't want to admit one of them!"
The problem though is that if we ignore stereotypes and limits completely and tell kids to do this we risk giving people unrealistic expectations. This balance is so challenging. I don't want white kids to believe that they can't run fast but at the same time I don't want any kids telling themselves that they don't need to do their homework because they have no natural limit and if they train they will be the fastest man in the world!
Balancing this is hard. They way I try and do it is emphasize that we do have limits - both genetically and lifestyle imposed. However you don't know what the limits are until you work hard at something... The harder you work the closer you get to figuring being able to get a handle on limits and when you do get some idea of what your limiting characteristics are you shouldn't necessarily just ignore them because your filled with self confidence that barriers are always bad!
In fact, part of the cruel irony of this is that while believing in your limitations and barriers can keep you from reaching your potential - so to can completely ignoring them... One of the greatest examples of this is Andrew himself! Think about Andrew's accomplishments and how he reached them. He tried to get strong and jump high. He read and researched and realized that he was limited in using the full squat to build his strength for his vertical - he recognized that limit and ignored dogma and half squatted and quad jumped his way to become a white guy jumping almost 40'' inches and blasting through barriers and making dunk videos. Getting near 40'' is an accomplishment. He power jumped his way to doing a DLRVJ that was damn near elite level through hard work. Could he have got to 42? 45? 50? Who knows. But along the way he realized some limitations (or a better way to phrase it might be some areas where he was less advantaged rather than more) and is now embarking on reaching the elite 40/40 dunking club. But he realized that he might be limited in how far he can progress jumping with a power two footed jump and realized that his best strength might not be carrying the mass and muscle necessary to jump like this and accumulate injuries - so he is switching to jump off one leg. This is achieved only by working hard and being realistic and knowledgeable about ones strengths. In the beginning there is no need to consider limits - he kept gaining cause he kept improving... without self-belief that he could jump he never would have made these gains... But at some point blind self belief that he can achieve his goals however he wants if he works hard could keep his focus on two footed jumping exclusively and he wouldn't be able to jump as high in the long run... This is why you have to be realistic with your body and know where you excel. It's also why you should have a general goal (like dunking or running fast) rather than a specific goal like running an incredible 200m or jumping high via squatting and two footed jumping only...
I had a track teammate who would dominate in practice and usually beat me in the 200m. The guy only wanted to run the 100m though. He was full of self confidence and in someways it served him well. He believed so strongly that if he worked hard (and he was the hardest worker) he would be great. He insisted he was a 100m guy but in meets would always near 11 and only broke 11 one time. He was full of excuses and mad that he dominated us in practice where we were fatigued and couldn't bring it in competition. FINALLY, his last year he ran the 400m with little training and ran 46.1. The were so many signs that he would excel at the 400m but he refused to do it because he ignored his "limits" or strengths and had to specific of a goal. If he just wanted to be fast he could have probably achieved so much***.
*** Just to illustrate how hard this can be it's important to consider who should make the switch or make a training change. It should only be you or someone you know extremely well... This is why it's so important to be mindful and aware of your training, your strengths, what works for you, etc. You have to balance patience with your coaches training and progress and work extremely hard while also being aware of what specifically works best for you... I have seen this happen countless times - a young sprinter comes to college after he had a good career in highschool running fast times in the 100, 200 and 400. Perhaps he runs 10.9 off of highschool training that includes cross country, basketball, and some poor track work. He hasn't lifted at all or done any real speed work. If he is lanky and white the coach will take him after the first day and use stereotypes to make the decision that he is a 400m or even 800m guy and force him to do an event where he never excels simply because the coach imposed a racist limit on him rather than give him the speed work and strength training that could have made him into a great sprinter... I truly believe that if someone like Christophe Lemeitre had grown up in the US he wouldn't be the first white guy to go sub10 because some idiot college coach would have forced him to run the 800m. If the athlete isn't aware he won't put up a fight when someone imposes limits based on stereotypes or limited data and it will cost him his ability to succeed...
We can look no further for an example than Usain Bolt. There is some terrible myth that Usain is lazy - but the truth is that it's just a myth - the guy pukes at practice daily. His coach used stereotypes (that he is tall) to decide he could only be successful in the 400m and maybe the 200m despite the fact that he ran an out of shape explosive 200m in 20.5 as a 15 year old... Bolt struggled at the longer distances and gave it a shot but at some point he knew his body and his ability well enough to ask/beg his coach for the chance to run the 100m.... His coach allowed him to and the rest is history...
TL;DR - Racial stereotypes suck. Stereotypes that involve achieving something that takes hard work are terrible for everyone. Ignore them and believe in yourself and know that you can do anything - but in the back of your mind be mindful that you might not be able to do ANYTHING but that you surely won't achieve it if you don't believe it... As you evolve as an athlete don't let limits and barriers effect you BUT be mindful of where you might be more successful if it is a change in technique, training, strategy or even and keep your goals general enough so that you are afforded the flexibility to achieve them in whichever way works best for you... In short, it's kind of like religion or faith in god. Love sport and athletics and believe that you can succeed and be great - but realize that (god) success works in mysterious ways - you will get your goal if you believe in yourself but it might not be how you envisioned it or exactly the same goal you had when you started out!
