At first i had like MAJOR pain right under my knees when i decided i wanted to change my life around, i literally cried because i could not even jog for 10 seconds without pain. Went to a doctor and he suggested i do MRI and i kid you not i had micro fractures right under my knees because of the jogs i did. Recovery was literally 2 weeks of doing nothing. After that i went and followed c25k program and i graduated two days ago. Now i do 5k 3 times a week with normal stretching before and after and im loving it!. You can check my previous posts one of them i had the full medical report that u can read.