I really believe that. It is the best big assistance exercise for your whole posterior chain. Traps, middle back, lats, lower back, abs, glutes, hamstrings.
I found out lots of endurance athletes are quad dominant. They suffer from knee pains, strained hamstrings, lowe back chronic pain. Enter the Romanian deadlift.
Hypers for lower back? GHR for hams? Leg curls for hams? Hip extension machine for glutes? GM for lower and middle back? Nope. You do not need all these exercises, you can get all in one, the Romanian deadlift.
I personally use Romanian DL once a week for volume work. I also pull conventional the same week. Yep, pulling twice a week. I really think it is the bare minimum. With Romanian DL I do 4 heavy sets of 5-8 with roughly 50-65% of may max pull or I do 2 sets of 20 with roughly 40-45% of my max pull. I do the Romanian DL as my last exercise of the day because I am tired as hell after. The 4 set of 8 are heavy and taxing but those 2 sets of 20 are the real treat. You'll be puffing as a locomotive and the next day your hams, glutes, mid back, lats and traps should be fried. But not the lower back. I will explain this later when discussing proper form.
Set-up
Closer than shoulder width stance, shins against the bar, knees slightly bent, no belt, overhand grip. Use straps if you must. Your upper back slightly rounded (yes, it's ok), arms gripping exactly when they fall from shoulders, lower back flat (not arched, not rounded), ass waaaay back.
Pull
Brace your core, pull in air, inflate stomach incl. obliques, pack your shoulders and start pulling by rocking back even more and putting all the pressure on your hams and glutes. Lower back must not round or arch, it must remain flat during the whole pull. You do not pull the bar up, you pull back towards your body. During the whole pull, the bar grazes your shins and thighs. It is your ass that travels backwards. Once above the knees, thrust your hips forward, squeeze your glutes and mid back. The next day your hams, glutes, lats and mid-back should be sore. Your lower back might be tender from doing the static work but never sore. If your lower back is sore, you did it incorrectly. The rotation axis is in your hips, not lower back. You return back the exact same pathway and pause the plates 2-3cm (1 inch) above the ground, wait there 1 sec and pull up again for another rep. Your lats will fight like hell during this pause keeping the bar where it should be and if you do it right, your lats will be sore as hell the next day. I personally think the Romanian DL is the best lat exercise out there. Yes, I just said that.
Romanian deadlifts boost your pull and squat and pack slabs of muscle on your hams, glutes, mid back, upper back, lats. Your whole posterior chain will get stronger. No more low back pain, no more strained hams.
I do not understand why so many people treat it as a fitness exercise using 2 x 10kg plates on each side and going for an exaggerated stretch. C'mon, put some weight on the bar. If you want stronger posterior chain you have to pull heavy. Period.
Now pull some damn weight!