I remember when I did it. I made a sudden increase to the load in my hamstring exercises. Afterwards I could feel a sore spot right up in the origin. So high I thought it was my glutes. Since then it has been the first thing I felt every morning. However, after just one session of eccentrics, this morning I woke up and was almost entirely pain free.
It’s almost like the problem was caused by a hard concentric contraction that bunched up the fibres, but the eccentric stress has stretched them out again.
I can’t believe how well and quickly it has worked…