Which exercise is an open-chain exercise that isolates the quadricep muscle?

The leg extension is an open-chain exercise that effectively isolates the quadricep muscle. In this exercise, only the lower leg moves while the upper leg remains stationary, allowing for focused engagement of the quadriceps without significant involvement from other muscle groups. This isolation is beneficial for targeting the muscle during rehabilitation or strength training.

Open-chain exercises, like the leg extension, are typically characterized by the foot being free to move, contrasting with closed-chain exercises where the foot remains fixed or in contact with a surface. This characteristic of the leg extension makes it particularly suitable for isolating the quadriceps, as the movement primarily stresses this muscle group and allows for more precise control over the exercise's impact on the quadriceps.

In comparison, squats and deadlifts are closed-chain exercises that activate multiple muscle groups, including the hamstrings, glutes, and lower back, thereby not isolating the quadriceps as effectively. The leg press is also a multi-joint exercise, engaging various muscles in the lower body, though it does allow for some focus on the quadriceps. However, it still differs from the isolation provided by the leg extension.