Anto saidThe main use of this kind of study will probably be as an easy excuse for people who aren't exercising hard enough or consistently enough.
It also can help people better understand why they may not be improving despite how hard they work as well. I think it's good info to know, help people from just running themselves into the ground trying to attain goals that may not be possible for themselves.
I think people that are out of shape have more than enough excuses not to be in shape. The trick is overcoming obstacles through intelligence, knowledge, dedication, desire, diligence, and a "never ending pursuit of constant improvement".
I agree many people kill themselves at the gym while burning a lot of time and calories, with desire and dedication, and nothing to show for it. Most of the time they are making big mistakes they are not aware of, and to blame serious genetic issues is almost laughable. That same person, with a knowledgeable trainer all of a sudden reaches their fitness goals in a few months.
I work at a gym, I see certain guys that work out 5 times a week, showing up through hell and high water for years at a time. They have absolutely nothing to show for it. Although I don't know their diet, from what I've seen at the gym it's because they never challenge themselves or their body to reach a fitness level that they have yet to obtain. They are lifting the same amount of weight they were lifting two years ago, and with the same routine.
Genetics obviously plays a key role in obtaining the upper echelon of fitness at the olympic level, but honestly, ALMOST everyone can achieve an incredible fitness level. Unless you have diabetes, arthritis, asthma(the list goes on I'm afraid) you really don't have too many excuses.
I think Morrissey said it best, and you should put this in your iPod for your workouts to remind yourself: