Let us speak on matters of logic. When one references the word “deadlift”, I do not think it is unreasonable to understand this to mean the “conventional deadlift”. We have taken to the fashion of adding the word “conventional” in front of deadlift as a matter of redundancy due to fairly recent developments of other deadlifting techniques, similar to how one now says “back squat” when referencing what is simply “the squat”. In turn, when we analyze the programs of yesteryear, if we view the word “deadlift”, it is fairly reasonable to imagine the author intended for this to be what was simply “the deadlift” when they wrote the program, rather than possibly “a deadlift”.
Always "a" deadlift, never "your" deadlift
In point of fact, I would be so bold as to state that the entire reason a sumo deadlift is even classified AS a deadlift stems purely from powerlifting competition rather than the simple evolution of weight training. In true powerlifting fashion, competitors analyzed the rulebooks of their federation, noted a requirement to move a bar from floor to lockout, noted no stipulation on hand or foot placement, and (those who had the leverages best suited for it) took advantage of this by developing a different way to deadlift. Contrary to popular internet opinion, powerlifting is not a sport where the strongest person wins, but instead a sport where the person who lifts the most weight wins. Maximizing leverages and minimizing ROM is crucial to victory, and breeds interesting techniques in the pursuit.
Don't hate the player, hate the game
We must note, however, that the sumo deadlift in turn merely meets the letter of the deadlift, but not it’s spirit. Yes, it is in fact a method of moving weight off the floor to lockout, but a quick glimpse will allow one to understand that it is vastly different from the conventional deadlift in terms of both execution and emphasized musculature. Do not misconstrue this statement, dear reader, as an attack ON the sumo deadlift, as is popular on the internet. I in no way am denigrating those who utilize the sumo deadlift, in competition or in training, for in the case of the former it is well within the rules and I applaud their competitive spirit, and in the case of the latter, as long as they are meeting their goals I applaud their efforts. Nor am I in any way saying that the sumo deadlift is EASIER, as is once again a very common attack levied against the movement. As a lifter who is far more oafish than elfish, the technical nature of the sumo deadlift is far more difficult to me than a conventional deadlift, and the reason I pull conventional (aside from the fact that sumo is not allowed in strongman comps) is because, for me, THAT is the easier deadlift. I am simply stating something that I am sure conventional and sumo pullers can both agree on: they are different movements.
The sumo deadlift is renowned for being far more technical than the conventional deadlift, whereas the latter is more about brute strength. The sumo deadlift recruits far more heavily from the quads and hips, whereas the conventional far more from the lowerback and hamstrings. The high bar squat tends to be a better assistance exercise for the sumo deadlift, whereas the low bar squat tends to benefit the conventional deadlift more. The list goes on and on. The point here is to understand that, despite the fact “deadlift” is in the name, these are different movements, which accomplish different goals and require different training approaches.
The most casual observer can understand that, despite this being the same guy, he's doing different things
Understanding this, I cannot understand why a non-powerlifting trainee would be inclined the substitute conventional deadlifts with sumo deadlifts in any program. As far as logical substitutions go, it is pretty far off, trailing behind choices such as Romanian deadlifts, stiff legged deadlifts, top down deadlifts, deficit deadlifts, mat/block/rack pulls, or pretty much any other deadlift variation where the mechanics still mirror the conventional approach. A powerlifter trainee in pursuit of a higher total has the most logical choice for their substitution, as they are simply utilizing a legal movement that will allow them a higher total, but for someone that simply desires to get bigger and stronger I ask, why this movement?
It seems we have once again missed the forest for the trees, thinking that the intent of deadlift is simply “pick weight up off of floor”, instead of thinking that it was put into the program as a way to develop the explicit musculature that a conventional deadlift develops in the way a conventional deadlift develops it. We are focused on form versus technique, fixating on the way the bar looks when it is moving rather than the way the body moves the bar. This logic is haphazard at best, akin to substituting a jerk for a strict press under the idea that, in both cases, the bar starts off in the racked position and ends up overhead. As with all things in training, we must ask ourselves “WHY are we doing this”?
My guess? Drugs.
It is from this that I am inclined to strike even harder at the trap bar lift. First, you will note my refusal to refer to this movement as the “trap bar deadlift”, as is witnessed in common conversation, due to the fact that it is these verbal gymnastics that lead to this confusion in the first place. The trap bar lift is its own lift entirely, and though it does involved breaking a dead weight off the floor, should not share classification with the deadlift proper. If we were to grant any movement that involves moving a dead weight the “deadlift” moniker, it would be necessary to have such absurdities such as “the bench press deadlift from pins”, or “the overhead press deadlift”.
In truth, the trap bar lift tends to share my similarities with the squat or hack squat in terms of muscle recruitment and technique employed, and its saving grace of being “easier on the lower back” is once again explicitly why it makes a poor choice for deadlift substitute. The deadlift is most definitely a brutal movement to the lower back, which is why any movement that removes this quality is most assuredly NOT an ideal substitution for the lift, for you are missing out on affecting some of the most critical musculature of the movement. I would even contend that the safety squat bar squat shares more in common with the deadlift than the trap bar lift, for even though a dead weight is not necessarily being broken off the floor, the upper and lower back are still being incredibly taxed and the mechanics of the low/high bar squat do not necessarily directly transfer to the movement. At the very least, if given the choice between the two movements and being told I had to pick one to improve my deadlift by 30lbs, 100 times out of 100 I would pick the safety squat bar.
This counts, right?
Once again, we witness that the choice of substitution hinges entirely upon the notion that, as long as a weight is being broken off the floor, we are accomplishing the goal of deadlifting in a program. In general, if we substitute a movement in a program and the end result is we have made things EASIER for ourselves, it is a safe bet that we have also made the program less effective, and the trap bar lift entirely exemplifies this. Again, I ask dear reader that you do not read this to be an attack on the trap bar lift ITSELF, simply a critique of its function as a deadlift substitute. The trap bar can definitely have its place in a routine, and I personally have employed it for high rep sets where the goal was to acclimatize the trainee to misery and strain due to the fact that, as fatigue set in and form deviation was present, there was less significant risk for personal injury compared to when using a barbell to deadlift. However, as far as actually achieving the same result that a deadlift does, it is lacking.
In sum, I reiterate my opening premise that not all deadlifts are created equal. We are willing to recognize the difference between the deadlifts when doing so is advantageous in us utilizing the one best suited for our anatomy or history of injury, but unwilling to acknowledge this difference when it comes to understanding the impact on our progress. Any time a substitution is made, it is the INTENT of the original movement that must be matched, not the appearance. As long as this is accomplished, we will meet our goals, but if it is not, we are simply spinning our wheels and delaying our ability to grow bigger and stronger.