ACE Personal Trainer Practice Exam

In an open kinetic chain movement, which part of the body moves freely?

1. The proximal part of the body

2. The distal aspect of the extremity

3. The trunk of the body

4. The core muscles

The correct answer is: The distal aspect of the extremity

In an open kinetic chain movement, the distal aspect of the extremity moves freely while the proximal part is generally stabilized. This type of movement allows for the individual segments of the limb to move independently, resulting in increased mobility and a greater range of motion at a specific joint. For instance, when performing an exercise like a leg extension, the knee joint is allowed to flex and extend without the influence of the hip joint or other proximal segments. This kind of movement contrasts with closed kinetic chain movements, where the distal segment is fixed, such as in a squat, where the feet remain on the ground. In open kinetic chain activities, emphasis is placed on the movement of the distal limbs, often leading to targeted training of specific muscles without the same level of engagement required from stabilizing muscles found in closed chain movements.