Hi all,
Ok, as a caveat, I am a final year physiotherapy student, but the nerve movement exercises he was giving you are called neural glides, neural flossing if you're an osteo, or something similar sounding. He will probably have done the slump test with you where you are asked to sit on the edge of the couch, you get put into position, and then you move either your head or foot to a new position to see if it relieves/brings on your neural pain.
In essence, nerves within the body can become trapped through tight muscles, and as such when you do particular movements, these nerves aren't free to move, and therefore give you problems.
The fact that you squat to relieve your pain would make me suspicious of lumbar spine involvement. You are relieving pressure on the nerve through squatting, but you are also potentially gapping the lumbar vertebrae. L5/S1 is a common source of problem and can refer to the places you state - i.e. your foot. In terms of your hamstring cramping, I would hypothesise that this is not related to sciatic type pain, but a remnant of the strain to your hamstring. How severe was it? If it was badly strained it could well still be weak - have you been doing any sort of rehab/strengthening exercises with it? Do you get hamstring issues without the foot pain? Do you feel like you trip up more, or have any foot drop or dragging? Any weakness that you have noticed to the foot/toes?
I have done a quick literature search on the effectiveness of neural glides for hamstring/sciatic problems, and the evidence is a bit sparse, but does point towards a benefit with performing this technique in the few papers available. The most recent one I could find that roughly matches what you have described is here:
CONSERVATIVE REHABILITATION OF SCIATIC NERVE INJURY FOLLOWING HAMSTRING TEAR
Maybe someone more experienced can give better anecdotal evidence from their practice. From personal point of view, I do neural glide techniques on people I see with sports injuries during my sports massage work, and it does seem to give relief from symptoms, particularly upper limb.
Exercise wise, you could try something like this:
33.3 Hamstrings Sciatic Nerve Mobility Exercise - YouTube
However, this position doesn't have the chin tucked towards the chest. I presume they are saying that they just want to tension the L3 downwards levels, but to put the whole neural system on a stretch, I would also advise have the chin to chest.
Hope that helps.