Certified Personal Trainer (NSCA) Practice Exam 2025 – Complete Prep Guide

To determine which exercise produces the most work using 220 lb (100 kg) at 90 degrees of knee flexion, the back squat is the most effective choice due to several factors.

The work done in an exercise is influenced by the distance the load is moved vertically during the movement. In the case of the back squat, the depth of the squat typically allows for a greater range of motion at the knee joint compared to the leg press variations. At 90 degrees of knee flexion, squats engage not only the quadriceps but also involve the glutes and hamstrings more significantly, leading to a comprehensive and effective movement pattern. Moreover, since the load is directly supported by the individual's body, stability and core engagement are maximized, enhancing the overall work performed.

In contrast, while the leg press is also an effective exercise, variations in the angle (such as the horizontal leg press, 15-degree leg press, and 60-degree leg press) can alter the range of motion and the biomechanical demands of the exercise. The horizontal leg press may not utilize as much vertical movement, which can reduce the overall work done. The different angles of the leg press can also change the distribution of force across muscles and the amount of knee flex