Is Ems applied to the hamstrings sufficient for their strength and hypertrophy in a program consisting of sprints, tempo, med ball, squats and Olympic lifts, or is direct barbell strength work required also?
Squats and Oly lifts work the hams also. Are you thinking of knee flexion?
No, only hip extension. Are knee flexion exercises neccessary for a sprinter?
I don’t think there’s much need for ham flexion exercises and they are more likely to cause a problem then cure one.