The people I know that complain about injuries don't actually exercise
I am no stranger to the bars / pubs. I regularly go to them in order to get some social time but I have to really keep my wits about me because one of the things I have a difficult time controlling no matter how dedicated I am, is my consumption of alcohol. I still go there though and people will often talk to me about how fit I look compared to years ago when the pub was basically my only avenue for doing really anything other than work and / or sitting at home watching Netflix.
I meet a lot of people there and many of them ask me advice about what my program is to lose and sustain weight loss. While i try to break it down for them in non-patronizing way and also attempting to let them know how achievable it actually is, I more often than not will run into the same excuses that I have heard so much over the years.
- My knees are too banged up for that
- I have shin splints
- I rolled my ankle years ago and can't put that much pressure on it
Bullshit

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I run a 10k 3-5 times a week. I am in my late 40's. I spent almost all of my late 30's and early 40's being a slob and sitting on my fat ass all the time. I used to get winded just walking up stairs. I avoided physical situations. I too complained about "bad knees."
The problem with these excuses is that it seems like almost everyone is looking for an excuse to justify their own laziness. They almost always have never had a clinical diagnosis either, they just felt like their knee hurt one day and webMD'd it and made it official.
As far as knees being "bad" is concerned, take a look at this website that is owned by a respected orthopedic care facility that doesn't sell anything related to running and how they have scientific evidence to prove that running is actually VERY GOOD for your knees. Yes, you read that right. Even though your knees may hurt after you run (mine do) it is kind of the same thing as your chest muscles aching after a bunch of push-ups. It's supposed to feel that way.
When it comes to older aged people, this excuse becomes more prevalent. However, an extensive Stanford University scientific study involving 5 MD's concluded that non-runners of the same age group and overall dynamics are 5 times as likely to develop genuine knee problems than runners are. Another study, that is too doctor-ey to really be consumed by most people, involved 75,000 participants across many types of exercise concluded that runners had a significantly reduced risk of arthritis of the legs than people engaged in less strenuous activities.
So cut the crap folks.
The reason why your knees hurt "more" than mine do when I go running compared to you is simply because I am used to it and you are not. There is no medical reasoning here to justify your lack of activity. In reality, the longer you put this off by making this tired excuse increases your inability to get involved in it at all in the future when you probably would really like to be involved in simple activities such as walking without pain.
I see jogging as an investment in my future as well as just kind of feeling better about myself when I complete something that was once very difficult for me to do, but now is just something that I knock out of the park a little bit better each time that I do it. When I was doing 5k's, I really struggled and would often give up before it was over. Then, MAGICALLY (sarcasm), over time the 5k became child's play and I had to step it up to 10k to feel as though I was doing "enough." Eventually, that number will continue to rise and rise and the hope / goal is that I will become an absolute unit that can run marathons.

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If your knees hurt after a run you need to understand that this is 100% completely normal. World-class runners and triathletes have knee pain after a run also. So again, cut the crap!
I don't lecture these people in my life that bring up this tired excuse when I speak to them, because I am not a pompous person. I don't brag about my physical achievements but I will recognize a compliment when I get them because I have been to the other side. I was a fat F**K that didn't give a damn about his size for YEARS. Then, one day, I took a look in the mirror and hated the guy that was in it.
I would imagine there are plenty of other people out there that feel the same way and to you, if you are one of these people, I have to say that there is only ONE person that can change this, and that person just happens to be staring back at you in the mirror as you look into it with disgust.
Seeing your reflection and not hating what you see there is quite an experience, and everyone without some sort of major real injury is able to accomplish this.
So stop talking about your "bad knees" and get out there and do it! You want my results? Well they don't come easy and they don't come free or fast. You have to work for it and after a week or so of "my knees hurt from running!" you will find that this pain starts to disappear and when you do get it, you relish it. It becomes, just like muscle soreness after a good lifting session, a sort of indicator that you did enough.
There are no shortcuts in the fitness world, but it involves dramatically more than sitting on a bar-stool and making excuses.
You gotta put in the work and eventually, the work itself becomes the reward.

I am not a qualified expert in this field. I have zero accredited certifications to give advice. What I do have is having graduated from the school of life as I saw myself go from elite athlete, to fat ass, and then back to fit and the strongest I have ever been in my life. I made a lot of mistakes along the way, but maybe you can learn from them so you don't have to also make those mistakes