Anatomy+
Biceps femoris (long & short heads)
The lateral hamstring. The long head extends the hip and flexes the knee; the short head only flexes the knee. RDLs and Nordics hit the long head hard; lying curls with a slight lateral bias emphasize this side of the hamstring sweep.
How to train this muscle
Knee flexion · Hip extension (long head) · Tibial external rotation