I have hurt my back in the past doing deadlift's. I now do them with a trap bar. No back problems anymore and I do not scrape my knees. It keeps my form strict as well.

 

Someone mentioned this may be the DOMS (delayed onset of muscle soreness).  That may or may not be true.  The DOMS do not show up that day... they manifest themselves 24-48 hours after the lift session and should dissipate within 24-48 hours.  If your pain is immediate/same day and is not getting better it probably is not the DOMS.

Deadlifts can be very injurious to the low back/L1-S5.  This will happen if the weight is too high; speed is too high; and/or form breaks down resulting in a rounding of the low back instead of maintaining the natural curve (think stick your butt out).

I don't think I've seen the type of deadlift that was done.  If your goal is to strengthen the glute max then you should definitely be doing bent knee deadlifts (as opposed to straight leg which loads the hamstrings).  Up to 40 percent of the glute max is attached to the illio-tibial (IT) band.  In order to actually fire those fibers of the glutes the knee needs to be bent 25 degrees to create the necessary tension in the IT band so the glutes have a solid anchor point.

The #1 reason for back surgery is back surgery.  Take care of your back and choose your exercises wisely.  Load, # repetitions, speed/tempo (eccentric and concentric), #sets and rest between sets (and workouts) are all valid parameters to vary your workout.  Beginner lifters should use a slow tempo (3-4 seconds on the eccentric phase of the lift) with higher rep counts (12-15 reps) and choose a load that they can manage fairly easily for the entire set/session.

For new lifters, much of the strength gain early on is a result of neurological adaptation... the brain is able to fire more of the fibers of the muscle, than it is mitochondrial (ability to burn energy).  Enjoy each lift and stay healthy.

It fully depends on what you are training the Deadlift for as well, as in what are your goals?

Crossfitting aside, as one of the most knowledgeable trainers I know once said, "An exercise program's effectiveness increases in direct ratio to the amount of stuff you leave out that shouldn't be there." Since the deadlift is an Olympic lift that is EXTREMELY taxing on the Central Nervous System, does it make sense for your goals to do it for high reps and suffer the muscle strain? It seems to me that, like what you said before, you see a direct correlation between three factors: number of deadlift reps done, amount of fatigue during those reps, and those fatigued reps with bad form causing subsequent muscle pain/injury.

Dan John (whose work every person who trains should look at) says "Plan the Hunt, Hunt the Hunt, Assess the Hunt." There is clearly a weak link in the chain and it is good you have discovered it now. I am interested to hear how you re-evaluated your program.

Hoss, can you speak more to this please?

I've never sumo deadlifted but i often do 2-3 warmup sets of traditional deadlifts followed by 4 sets of roughly 8 reps each.  NOW, i don't lift much compared to some shorter, beastier dudes with my long a$$ arms and legs, but wondering your thoughts.

As for repping out on the deadlift, the more tired you get the more your form suffers.  And the last thing you want to be doing is having your form going down the toilet when you're doing an exercise that for the most part allows people to move the heaviest weight they can.

Hoss is right on here. Putting the central nervous system under the stress required to move heavy loads in an Olympic manner is bad enough, but when you start adding in fatigue, bad things tend to happen rather quickly. The last thing anyone should really do is turn a complicated strength movements with a low "margin of safety" (that is, if you f*ck something up, you are pretty much screwed) for metabolic work is straight asinine.

In my younger days, I competed in several strongman competitions.  The event I always dreaded was the deadlift for reps event as it would wreck my body for days afterwards.  Highly technical lifts like the barbell clean and jerk, snatch, and deadlift done for high reps is just asking for injury and is darn irresponsible to be urged to do in my opinion.

If you still wish to train in this manner, I'd recommend switching to sumo deadlifts over conventional.  It's a lot more forgiving on the body to bang out reps in sumo than conventional.

This post says it all really.
Definitely switch to sumo DLs if you're going to continue on the CF path.

Deadlifts themselves, are an awesome exercise, when performed in a controlled and concentrated manner. Form is everything, because real life changing injury is one wrong move away.