Final answer:
The Sit and Reach Test is the most common assessment for low-back and hip joint flexibility. The hip joint, which is a multiaxial ball-and-socket joint, contributes extensively to this kind of flexibility.
Step-by-step explanation:
The most commonly used assessment for flexibility in the low-back and hip joints is the Sit and Reach Test. This test is designed to measure the flexibility of the lower back and hamstring muscles. The hip joint, being a multiaxial ball-and-socket joint, provides a wide range of motion, which is critical when performing tasks such as bending down to touch your toes.
During such a movement, the correct answer to what angular movements occur at the hip joint and knees is that the hip joint is extended and the knees are flexed. The hip joint is integral in this motion, and it is a complex structure made stronger by supporting ligaments that pull the head of the femur into the acetabulum when standing.