Hi. I am training for half marathon since February, from there i have managed to run around 6-8 miles. But recently i have not be able to run more than 1.5 miles as my knees gave away all the time.I don't have arthritis on my knees, and I have tried to use rolling foam but still the pain keep coming back everytime i run more than 1 mile. Is there anyone know why and what caused it? Is there anything i should do to fix this? The half marathon is on June, so i need to get out there soon. Thank you.