This hamstrings play a small role at the bottom of squats when the pelvis tilts anteriorly. That creates a stretch reflex response at the “Proximal” end, causing the hams to contract, but it’s not an active contraction. The lion’s share of the work is being done by the glutes and the quads. The former pulls the femur back down and pushes the pelvis forward and up. The latter pushes the femur down and back and the tibia up and back.
Good find, btw.
Must say you Sir seem wery knowegable in anatomy.
What is Your occupation if i can ask?

And i heard that about sprinting.
Use some form of it running up and down a hump of sand.
Also jumps to front and side to side.
Of course Squat is my main movement.