Hamstring pain? Weak hammies? The hamstrings have two major functions: extension of the hip and flexion of the knee. People can be great at one and not the other. For instance, someone recently mentioned in our community that they have no issues deadlift and doing hip extension exercises, but as soon as they do knee flexion exercises, their hamstrings start to cramp. Cramping of a muscle is often a sign that the muscle itself is weak - or that it isn’t used to being activated in that particular