The flawed
assumption for decades has been all about "impact" and how that's somehow the source of all running injuries. Cushioned shoes have been the solution desperately searching for that problem. But every time a study is performed to try to find a link between horizontal impact or load and injury ... inconclusive.
More recently they've found a very strong link along the
horizontal axis:
https://www.runnersworld.com/news/a21343715/lower-your-running-injury-risk/
tl;dr - step your feet too far in front or scratch them back too far behind and you get injured. You know what also happens when you over-extend your feet like that? Your hips twist too far, your lower back twists too far ... you get lower back pain.
Turns out human legs are
incredible shock absorbers. We can handle vertical load all day long just great. What we can't handle is a lot of excessive horizontal jarring. Put on a pair of modern athletic shoes and what to you get? A snug fit and super grippy rubber tread. Get those out on a solid, paved surface and you've got way more grip than evolution prepared us for.
Take the shoes off. Run on concrete. If you're over-extending your legs that skin will hurt. Keep going and that skin blisters. Maybe tougher skin will help? Nope. Skin gets thicker over months and years of unshod running but excessive horizontal braking will now result in thicker blisters. I spent a year praying to the Magical Tough Foot Fairy that one night she'd bless me with tough feet. All I got was more bruises and blisters. Just doesn't happen that way.
Not only are we able to handle vertical load better than horizontal think about what direction your momentum is going while running. How much does your head bob up and down? A few inches? That's your vertical oscilation. How long is your stride length? A few feet? That represents your horizontal movement. It's greater than your vertical by an order of magnitude. Literally 10x more is going horizontal than vertical when you run.
That's why even just a little bit of over-striding is so bad. If you never got injured over-striding you're still slamming on the brakes with each step making you inefficient and fighting against your efforts to move ahead.
So think about that for a while. The idea that "impact" is a problem is an old, flawed assumption that's simply not been proven. Your legs aren't just great shock absorbers they're loaded with springy, elastic tendons that have evolved to bounce you along hard ground effortlessly. What would you rather bounce a basketball on? A wrestling mat or concrete? What would you feel more stable standing on? A waterbed or concrete? That's what your relationship should be to soft surfaces vs hard.
And all that is to further prove why forums like this exist. When you take the shoes off and expose that easy-to-blister, super sensitive skin to concrete you finally start learning how to move better. Evolution crafted our legs to work their best and strongest in tandem with the specific properties of bare feet. Shoes with a snug fit and super grip encourage you to over-extend those legs and use them where they're weak and vulnerable. The whole rest of your body takes the brunt of that abuse resulting in a host of problems including back pain.
Sitting all day certainly doesn't help. But keep all this in mind when you run. Square your hips, square your shoulders, tall posture, head high, feet working the ground directly under your hips. Those same tips apply to every sport not just running.
edit: and since you ask about distance running and barefoot: I've done two full marathons in totally bare feet on city streets. I've also done 20 miles of a 50k across gravel, dirt and rocks unshod and 11 miles of a 50 miler that way. The rest of the miles for those ultras were done in my trusty, hard-soled Luna Origen sandals. Literally car tires with leather straps. Best trail footwear I've ever had! Even after all that ... I ran a 1/2 marathon in bare feet in October after training all year for that 50 miler. Blisters! I hadn't run at that kind of fast pace for that long before. I supposedly have "tough feet" due to years of unshod long distance experience. But push myself too hard, do something I haven't done, let my form slack. I got those thick blisters I talk about. It inspired me to start doing 100m dash repeats on the street unshod to learn better.