Doing DL's while standing on secure blocks (we have a small platform..easy to make) is, as HedgeHog suggest, a learning tool and that's all. Anything near using serious weight should be avoided. Correct ab and lower back involvement (and how they work with one another) can also be learned better from this starting position. As well as the importance of timing the breath. Your just learning the movement, which should be kepted in mind during the total lift, not going for a PB. So a lighter weight (or even the bar) and higher reps can be preformed to set up the motor units.
SLDL's can be very rewarding when the regular 45's are used from the floor. A hundred to one fifty lbs below your regualr DL workout poundage can be used. If you do SLDL's off a block please hold caution in mind. GM'ing, in my mind, are number one with regards to strengthing the lower back and increasing the DL poundage. Also hold true in giving better squating power.
If you think full DL's are king and don't want to do partial DL's (around knee high) or lockouts (4-6" to top) than use a trap/shrug bar. The hands are in a more natural position and the knee's should not get in the way of the lift. You will not have to lean too much forward to avoid scrapping the shins or knees when using this type bar. And in return, put too much unneeded stress on the lower back.Good Luck.
