When animating limbs with IK, the resulting motion often looks like the character is a marionette with its wrists on puppet strings. This is the result of simply animating the trajectory of the IK handles in straight lines. One solution is to animate your character s limbs with FK, which will result in arc motion by default. Simply setting an initial translation keyframe at point A then a destination key at point B will result in a linear trajectory and a marionette look. Intermediate keyframes are often required to create an arc trajectory.
Linear trajectory is okay, assuming that is the intended result.
Just remember that such motion is not the normal tendency of a jointed character. And since very few real-live characters ever actually freeze completely, when a 3D character does so, it can look unnatural and the action of the scene can die completely. Use moving holds instead, where your character maintains a small degree of motion. Just enough so that the scene doesn t entirely stop dead, but not too much or the pose will no longer be a hold . Perhaps he takes a breath or scratches his ribs.