sit ups

Dumbbell adapted to be held behind user's head while performing sit-ups
The difficulty of sit-ups tests: an empirical investigation
Muscle Activity During Sit-Ups Using Abdominal Exercise Devices
Neurologic complications of sit-ups associated with the valsalva maneuver: 2 case reports
Relationship of push-ups and sit-ups tests to selected anthropometric variables and performance results: a multiple regression study
Exercise device for use in the performance of sit-ups
Apparatus to aid in performing sit-ups
Rectus abdominis rhabdomyolysis after sit ups: unexpected detection by bone scan.
Sit-ups, other exercises may injure older patients with osteoporosis
Relationships between Sit-Ups and Abdominal Flexion Strength Tests and the Thickness of Each Abdominal Muscle