How is running bad for our joints? Maybe if you do it on concrete in a bad shoe, but the human body was literally made to run - which is very apparent from its design (our thighs are basically a spring that can “charge up” slowly in the “up” phase of running for less energy usage + no hair and improved thermodynamics (people can literally run for longer distances than most other animals with very few exceptions)), and you can even feel it yourself, like no other sport has such a short getting up to speed phase. If you start running for a week, you will already feel a huge improvement, unlike in tennis or bodybuilding where it might take months to noticeably get better.