Hip Flexor Workshop: Part B
Observing Range of Motion
In image 3 the thigh drops easily into extension. It is a sign that the one joint hip flexors are not tight.
However, the knee does not bend easily. Assume that the quadriceps are tight in this case.
In image 4 the hip drops easily into extension and the knee bends easily too. There is probably good flexibility in both one joint hip flexors and quadriceps in this case.