At a first glance it may seem as a simple exercise. It does not require much special equipment, and if there is no bench you can even use a couch or a bed. Seems that it trains a minor muscle, muscle that's responsible keep our spine health.
Spinal injury is the second most common injury in the fitness industry after shoulder injuries. Statistics do not lie, if you among those who do deadlifts, Good Mornings and Barbell rows. The only thing that separates you from injury is how strong your lower back. And it is probably weaker then you might think due to the sedentary life most of us live.
This exercise is unique in so many ways.
The safest exercises to strengthen your lower back. CHECK!
Can be done even with back pain and disc injury (herniated disc)* CHECK!
Hard enough to stimulate muscle growth. CHECK!
Feel that the exercise is too easy? Put on your heavier boots.
*With any back pain, you should always consult with your doctor before you do any exercise.
Focus on lifting the glutes - The exercise should work your lower back and glutes, focus on lifting the glutes up, not on lifting the feet or legs.
You can bend the knees to make the exercise easier If you find straight legs being to hard, bend the knees until the feet touch your butt, then raise the legs while bended.