Back when I was in military service, we had a fitness test that involved a 2.4km run. In order to get an “A” for that part of the test, we had to run it in under 9:45. A month before the test I was doing 11 minutes. I spent the next four weeks doing 3-4km runs in my heavy field boots and jeans till I could clear the 2.4k in 10 minutes. On test day, I ditched the jeans and boots for PT kit and runners and ran 9:15. Success from running in jeans!
Write that down. Remember it.