AFAA Personal Trainer Certification Practice Exam

In an open kinetic chain, what characterizes the movement of the limbs?

1. The distal end is fixed to a surface

2. All joints move simultaneously

3. The distal end is not fixed, allowing independent joint movement

4. Only the proximal joints are allowed to move

The correct answer is: The distal end is not fixed, allowing independent joint movement

In an open kinetic chain, the key characteristic is that the distal end of a limb is not fixed to a surface, which allows for independent movement of joints along the limb. This freedom of movement means that the actions at one joint do not significantly affect the other joints in the chain, thereby providing the opportunity for isolated muscle strengthening and dynamic flexibility. For example, when performing a leg extension exercise in an open kinetic chain, only the knee joint is primarily engaged while the ankle and hip joints do not need to move in unison. This distinct feature contrasts with closed kinetic chain movements, where the distal end is fixed, resulting in coordinated movements across multiple joints. In this way, open kinetic chain exercises are particularly beneficial for targeting specific muscles without undue strain on surrounding joints.