I have been performing single leg hyperextensions on a Roman Chair. I have progressed to where I can perform sets of 8-10 repetitions with 170 lbs of resistance. The resistence is in the form of three fifty pound Universal rectangular plates plus two conventional ten pound plates, which I am able to reach under, and are moved when I am contracting my hamstring(s).

My problem is that my hamstrings remain sore. For example, in late January the hamstrings remained sore for three weeks. At the end of this three week period, while the hamstrings were still sore, I decided to exercise them again. Consequently, three weeks after that exercise session my hamstrings are still sore.

I should note that while performing the single leg hyperextensions I experience little or no discomfort in the hamstrings.

The longest I can recall having soreness from other exercises in other body parts is three or four days.

Why won’t the hamstrings recover from this exercise? What is there about this exercise which so stresses the hamstrings that they will not recover?