What does it mean if the proximal segment is fixed and the distal segment is freely moving?

When the proximal segment is fixed and the distal segment is freely moving, this configuration describes a closed-chain movement. In biomechanics, closed-chain exercises involve the distal segment of the body (such as the hand or foot) being in a fixed position, typically in contact with a surface (like the floor). This means that as the distal segment remains stable, the proximal segment of the body must move relative to it, which can contribute to greater stability and proprioceptive feedback.

Closed-chain movements engage multiple joints and muscle groups, leading to functional activities that reflect everyday movements, such as squats or push-ups. These exercises often enhance strength and coordination and are known to be particularly beneficial for joint stability.

In contrast, open-chain movements involve the distal segment moving freely in space, often away from a stable base, which focuses tension on a particular muscle or joint without the same level of stability provided by a fixed proximal segment. The remaining options pertain to other biomechanical principles related to joint positioning but do not accurately describe the scenario of fixed proximal and moving distal segments.