Which type of exercise involves a distal segment of the body moving freely in space?

The correct answer is open chain exercise. In an open chain exercise, the distal segment of the body, such as an arm or leg, moves freely in space while the proximal segment remains stationary. This type of movement typically allows for greater range of motion in the isolated joint being exercised, as the limb can move independently without being fixed to a surface.

For example, movements such as leg extensions on a machine or arm curls with dumbbells are considered open chain exercises because the feet or hands are not anchored, allowing them to move freely through their complete range of motion without the resistance of weight-bearing load. This aspect makes open chain exercises particularly effective for isolating specific muscles and focusing on strength training.

In contrast, closed chain exercises involve the distal segment being fixed, such as during a squat or push-up, where the hands or feet are in contact with a surface, resulting in a different type of joint and muscular engagement. Understanding the distinctions between these exercise types helps athletes and trainers select the right approach based on training goals and rehabilitation needs.