Anatomical Structure

Anatomical structure affects movement ability in the hip by the single non jointed structure of the pelvis. The pelvis rotates all three planes of movement. One movement is the rotating of the femur so that the acetabulum is positioned toward the direction of approaching femoral movement. Another is the posterior pelvic tilt, when the anterior superior iliac spine is tilted backward, it position the head of the femur in front of the hipbone to enable flexion. Lastly, anterior pelvic tilt enables femoral extension, and lateral pelvic tilt toward the opposite side facilitates lateral movements of the femur. Movement of the pelvic girdle also coordinates with certain movements of the spine. There are six muscles which are responsible for flexion
They are mainly movements permitted at the tibia femoral joint. The three hamstring muscles play a role as the primary flexors. Muscles that assist with knee flexion are the gracilis, sartorius, popliteus, and gastrocnemius. (Hall,236)The quadriceps muscles affect the movement by consisting of the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius, they are the extensors of the knee. Tension development in the semimembranosus, semitendinosus, and popliteus produces medial rotation of the tibia, with the gracilis and sartorius assisting. The biceps femoris is solely responsible for lateral rotation of the tibia. Abduction and adduction moments at the knee can also be actively generated by contracting of the muscles crossing the medial and lateral aspects of the knee to resist externally applied adduction and abduction
Fractures occur although the pelvis and the femur are large and one of the strongest bones, the hip is high for repetitive loads ranging from four to seven times body weight during locomotion. Fractures occur frequently in elderly with osteoporosis which occurs during the support phase of walking. A contusion happens when the muscles on the anterior aspect of the thigh are in a prime location for supporting blows during participation in contact sports. Strains occur because most daily activities do not require every day hip flexion and knee extension; the hamstrings are not commonly stretched unless exercises are performed for that specific purpose. The knee common injuries are anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament injuries blows, meniscus injuries, and iliotibial band friction syndrome, patellofemoral pain syndrome, and shin splits. Injuries to the ACL are common in sports because it involves pivoting and cutting. Most of these occur when the femur is rotated on the planted leg with the knee close to full extension during cutting, landing, or stopping. These kinds of activities such as accelerating and decelerating involving sudden changes in direction which produce large rotational moments of sudden forces at the knee, particularly when such movements are not planned. Posterior cruciate ligament (PCL) injuries most commonly occur from sport