How does a joint move when there is tension on the muscle attachment?

When there is tension on the muscle attachment, the joint experiences forced movement toward the tensed muscle. This is due to the fundamental principles of biomechanics and muscle physiology.

When a muscle contracts, it generates tension through its attachment to bones via tendons. This contraction pulls on the bone to which the muscle is attached, creating movement at the joint. The direction of joint movement typically occurs toward the origin of the muscle, where the muscle is anchored in place, facilitating the movement of the distal segment of the bone at the joint.

For instance, during a bicep curl, the biceps brachii muscle contracts, creating tension that pulls the forearm upwards towards the shoulder, resulting in the flexion of the elbow joint. This movement illustrates how the muscle's tension directly influences joint movement, thereby supporting the understanding that when a muscle is tensed, the joint is influenced to move closer to the muscle origin rather than away, nor does it remain stationary or increase its range of motion without the action of muscle tension.