This post is dedicated to Daniel Law! Thanks for your contribution Daniel.
Romanian Deadlifts - this exercise is where you start with the bar in the high hang position - basically with your arms straight. You proceed to bend over from your hips. This is a great exercise in strengthening your hamstrings and back muscles as well as learning how to move from your hips and not your back. This exercise is also good if you have bad knees or weak quads as you don't use them so much.
Warning - Doing This Exercise Incorrectly Can Cause Injury!
I have seen too many people over the years do this exercise incorrectly. Most people lack the flexibility needed in the hips and so they bend over from the lower back...this can cause a disc injury!! The tell tale sign is like the guy in black on the right - He is rounded in his lower back.
Who Should Do This Exercise?
This is one of my favourite exercises too! I teach it to nearly all my back pain patients. Learning how to bend from your hips is essential to protecting your back. Doing this movement properly allows you to bend over and pick up heavy things more safely. Having stronger back and leg muscles help protect your back and increase your strength. Also, you can increase your flexibility in your hips and hamstrings with regular practice. What is there not to like about this exercise (when done properly)!?
The Technical Stuff...
There are lots of things to consider: Grip, weight, foot position, knee travel path, hip dissociation and movement, a strong straight back with properly balanced abdominal control, a torso that is not too extended but not too flexed, shoulders that are in the right position and where exactly should you put your neck - all of these things can be covered with a good physio or one of my degree qualified exercise scientists.
Here is one that looks ok...
Here is a video where this guy DOES bend in his lower back too much (despite what the guy in the video says)