yeah, running on concrete is hard on your joints. it can actually cause permanent knee-joint damage if you do it too much. thats why its good to run in gyms on like treadmills n stuff. my mom has some knee problems when she goes on concrete too much.
DON'T WASTE YOUR MONEY ON INTERNET HEIGHT SCAMS - 99% OF THEM DON'T WORK - - YOGA STYLE STRETCHING, KICKING, HANGING & EXERCISES ARE THE ONLY WAY TO INCREASE YOUR HEIGHT IF YOU ARE AN ADULT (OR RISKY, EXPENSIVE SURGERY!) WE'VE RESEARCHED EVERYTHING AND CAN TELL YOU WHAT'S A SCAM AND WHAT IS WORTH CONSIDERING. IF THESE SO CALLED "MIRACLE" PRODUCTS ADVERTISED BY THESE INTERNET COMPANIES WORKED, THEY WOULD BE ON BILLBOARDS, TELEVISION AND THE RADIO AND WOULD BE KNOWN WORLDWIDE!!!!!