Physical Therapy Assistant Practice Exam 2025 - Free PTA Practice Questions and Study Guide

During an anterior step down from a platform, the quadriceps in the stance leg engage in an eccentric contraction. This type of contraction occurs when the muscle lengthens under tension, which is essential for controlling the descent and maintaining stability as you lower your body.

While stepping down, the quadriceps must manage the force of gravity and the weight of the body, gradually lengthening to slow down the descent and prevent collapsing or falling. This controlled elongation helps stabilize the knee joint and supports proper alignment and movement patterns, ultimately reducing the risk of injury.

Understanding muscle contractions in this context helps to inform rehabilitation practices and exercise programming, particularly for functional movements that involve balance and control. Eccentric contractions are crucial in activities that require deceleration and lowering, making them important to recognize in physical therapy and rehabilitation settings. Other types of contractions, such as concentric, involve shortening the muscle, and isometric involves no change in muscle length, which are not applicable in this scenario of a controlled descent.