Human Functions Test 1 Practice

Stabilization during movement comes from the core muscles, which brace the spine and pelvis to create a stable base for the limbs to work from. The core includes the deep abdominal muscles (like the transverse abdominis and internal obliques), the surrounding abdominal muscles, the pelvic floor, the diaphragm, and the muscles of the spine (such as the multifidus). When these muscles engage, they increase intra-abdominal pressure and stiffen the trunk, helping maintain proper alignment and transfer force efficiently between upper and lower body. This stability is what lets the glutes, quads, and hamstrings generate powerful, controlled movement rather than fighting to hold the torso steady. The gluteus maximus drives hip extension; the quadriceps extend the knee; the hamstrings flex the knee and assist hip extension. These are primary movers for specific joint actions and contribute to movement, but stability during those actions mainly comes from the core.