The hamstring originate from your ischial tuberosity, the bony bits you can feel when you sit down on your bum.
It’s also the distal part of your pelvis.
When your hamstring pulls it sends your pelvis into a posterior tilt and flattening out your lumber spine.
We can use our hand to feel when the lumbar spine starts to press into our hand. This is true hamstring length.
More than a 10 degree difference in hamstring length left leg compared to right then this may create unnecessary torque in your spine.
