Long lever abdominal exercises are popular. However, they also pose a risk for the lumbar spine given the relatively poor abdominal strength/control and lever arm created by momentum and the iliopsoas muscle. The stress on the lumbar spine is high as the leg (s) come back down due to reverse muscle action via the attachment of the iliopsoas on the lower lumbar spine. As a result, this can cause a sizable shear force on the spine.

I counsel patients and athletes with prior history of disc pathology to be very careful with any long lever or ballistic abdominal exercises with straight legs as the physics may present higher risk than reward and create excess strain on the spine. While a single workout may not cause harm, there can be a gradual repetitive overload that creates weakness or harm to the disc and/or spine. This exercise from my Functionally Fit column promotes strength and core or pillar stability through resisting excessive spinal extension.