The correct answer is 4. Closed-chain exercises involve the body moving over a fixed distal segment, and these activities are often integrated into lower extremity strengthening programs. In contrast, chain exercises involve the distal segment, usually the hand or foot, moving freely in space. Thus, isokinetic knee extension and flexion require the distal segment to move freely in space, which is considered a form of an open-chain exercise.
Exercising on a stair machine requires the patient to maintain contact with the stair mechanism with their feet, which would maintain the lower extremity in a fixed position.
Limiting squats to 45° requires the feet to stay in contact with the ground while the hips and knees are gradually flexed, and the trunk remains erect.
Walking backward on a treadmill, or retro-walking, requires the lower extremity to be in contact with the treadmill for most of the activity and is therefore considered a form of closed-chain exercise.
Create a Free MyAccess Profile
AccessMedicine Network is the place to keep up on new releases for the Access products, get short form didactic content, read up on practice impacting highlights, and watch video featuring authors of your favorite books in medicine. Create a MyAccess profile and follow our contributors to stay informed via email updates.