In my Pathology book by Goodman, it states that flexion activity is contraindicated for people with osteoporosis and we should focus on extension activities. I don’t understand why flexion would be contraindicated.

The results of a 1988 research by Sinaki and Mikkelsen indicates that flexion exercises for patients with osteoporosis are contraindicated. In their study, these authors demonstrated that patients who do flexion exercises versus those who do extension, extension and flexion and no exercise, show a severely increased fracture rate.

Trunk flexion places an unnatural load on the lumbar spine causing fractures. Flexion activities may cause small fractures over time weakening the spine further or they can result in one large fracture, possibly leaving the patient immobile or debilitated. The International Osteoporosis Foundation also advises against picking things up off the ground from a standing position and seated stretches that involve reaching forward towards the toes.

Even though the texts recommend focusing on extension exercises, sustained spinal extensions or spinal hyperextensions are also contraindicated for patient safety.

Reference 1, Reference 2: Sinaki, M., & Mikkelsen, B.A. (1988). Postmenopausal spinal osteoporosis: Flexion vs. extension exercises. Archives of Physical Medicine and Rehabilitation, 69: 277-280.