Moving outwards from the spine and the pelvis, you have the hip joint which creates the anchor for the lower extremity. The hip is a ball and socket joint that moves in all three planes of motion. Mobility restrictions, weakness, and poor movement coordination at the hip are highly correlated with knee and ankle injuries https://www.ncbi.nlm.nih.gov/pubmed/29116830. The hip and the ankle act synergistically to absorb the shock of ground reaction forces during impact activities such as walking, running, and jumping. Failure to adequately absorb shock due to joint stiffness, muscle weakness, or a poor movement strategy commonly results in injuries to the ligaments, bones, and cartilage.
Lack of hip mobility, weakness, or poor movement coordination can also result in injuries to the spine - especially during flexion activities such as squatting. For instance, squatting deeper than your available hip flexion range of motion allows is a common mechanism for low back injuries such as muscle strains and disc herniations.