Q&A: Pain Behind Knee/Max Deadlift Calculations/Cross Training/Pain Guidelines

My hamstring pain is right behind the knee. Should I go through the same exercise and recovery regimen as PHT?

How do you determine the max weight you should use for a specific exercise (is there a calculation/formula)? Once you are in the maintenance phase, can you reduce the weight used and it still is effective?

I love running long distances (marathons and 50Ks), but am willing to take a break while I focus on recovery for my PHT. Do you have any suggestions for other cardio that wouldn’t aggravate it?

Should I be pain-free post-exercise to progress? Or is low-level but stable pain ok to progress cautiously?