I'm not Cathe, but I find that a nice variation of the hamstring roll-ins helps with hamstring strength and definition:
Put ankle weights on, and have a dumbbell handy; lie (lay?) face-up in front of a sturdy chair so that your butt is close enough in that when you place one heel on the seat of the chair your thigh is almost perpendicular to your torso. Extend the other leg straight up so that the entire extended leg is perpendicular to your torso. Place the dumbbell across your hips, low enough so that it is near the pubis. Press through the heel of the foot that's on the seat and lift your hips off the floor slowly and with strict control, and slowly lower back down. Repeat this for 8-16 reps, then reverse the legs and execute an equal number of reps on the other leg. Do as many sets of this as desired.
You can increase the intensity of this even more by angling the lifted non-working leg so that it is closer to 45-degrees of flexion rather than 90 degrees. Note however that this can really tax the hip flexors and in fact mass them up a bit, which might give you more mass in the quads than you desire.
HTH -
A-Jock
