I want to talk about to do healthy sport. Every day more and more friends and acquaintances start to do extreme sport and they are thinking that they are doing healthy sport. In my opinion, to begin to run marathons at 40's is doing extreme sport. I'm more 50`s and the body feels that the time falls above you, as a consequence, the knees say, for example: I'm 50 years old!
I have always done sport due to in my family, for instance, my brother started to do gymnastic early age, my mother and my grandfather they used to walk by the mountain when they could, ... I understood that doing exercise was an integral part of my live. Moreover, to do sport was necessary to be a healthy life as well.
Why people to start to do sport that maybe could be bad to the body?
In my point of view, when people mature/grow they want to have new challenges in their lives. I think that their mind it will feel good when they get this objective. In this point, I agree with them: people need to have goals, and this is a point a favour.
On the other hand, I disagree in this kind of objectives because the consequences to the body could be bad. Furthermore, it seems that if you don't do some extreme sport, you are a weak person. Messages from Facebook, Instagram, Twitter... are related that: you have to do things that it involves a big physical effort because only then you will be a strong person. These messages are very negative to person who has weak mind.
In summary, I think to do sport should be part in our lives, but healthy sport that you can practice it any age.
I always say to my students that the best business model to the future will be customized prothesis knees. When I see some people run and if I would make these prothesis I would give them a business card with my telephone number. I'm sure that someday they would call me.
It mustn’t forget why a marathon is called like this and what it happened to Pheidippides after to run 42.195 kilometres.