Yay i get to be superman/woman. Please read the bottom of my previous post, where i clarified my mistake. As yet i haven't tested with a partner however at the gym today i did some testing of my own.

On the hip ext machine at 60 kg, i found i could do around 20 reps on the right side (with some right sided SI niggles) and about 30 reps on the left. It just felt easier. I stood with straight legs and started the movement with my legs together, mimicking a SLR. It was hard for me to tell the relative contribution of hamstrings to gluts. I know the hamstrings were working, but this is also affected by the setup of the machine itself with the pad behind the knee. I also really felt the hip abductors of the support leg working hard- no differences noted though. An interesting feeling happens when i extend the hip- i feel like almost bruising between the lower sacrum and the pelvis but it feels good to keep extending and tensing the gluts it lessens.

On the seated leg curl machine, i did single leg curls. I'm not sure of the exact weight as it was just numbered. The left and right sides were approximately equal, i could get a rep or two more out of the right than the left if i pushed it. I think that's pretty normal though, a leg dominance issue. However, i had a harder time controlling the left leg, returning the weight smoothly without jerking or stopping in random places.

I tried leg ext machine and could actually do about 5 or so (i say or so because i wasn't 100% motivated!) more reps on the left than the right. I think this may be because about 3-4 years ago, i injured my left ITB and did heaps of VMO exercises on the left side. Like before, the left side was jerkier and less controlled than the right- i think this is a motor learning/control issue from not using that side as much.

Thanks for all your help