Leg curls with ankle weights
The exercise can also be done lying on the tummy with ankle weights, slowly bending the knees and bringing the heel towards the buttock, and then slowly bringing the leg down again. Leg curls improve hamstrings strength.
Functional and Neuromuscular Changes in the Hamstrings After Drop Jumps and Leg Curls. Sarabon N, Panjan A, Rosker J and Fonda B. J Sports Sci Med. 2013 Sep; 12(3): 431–438.