We all know that, broadly speaking, there’s a relationship between how heavy you are and how much you can lift. Various other factors are at play, of course – two 83kg guys at 5’6 and 6’0 have different jobs to do while deadlifting, and even if they remain the same weight, they’ll (hopefully) look and lift differently after five years of training than as rank beginners. But all other things being equal, though us small folk may comfort ourselves with the fact we lift more relative to our bodyweights, bigger people lift more overall. How much more, though? Is really heavy better than pretty heavy, or are the extra kilos worth less the more of them you’re carrying around already?
The graph above shows the rough relationship between bodyweight, bench and deadlift (squats overlap with deadlift quite a bit and cluttered up the graph, so I’ve left them out). The table below breaks the relationship down into the apparent effect of an extra kilo of bodyweight on each lift, in both men and women, within three composite weight categories. This is all based on the results of the 2012 RAW World Championships; the results might well be different for novices or intermediate lifters, and I’ll probably look at that in future.
For men lifting raw at world’s, an extra kilo of bodyweight translates to around an extra 1.6kg on the squat, 0.9kg on the bench, and 1.1kg on the deadlift compared to someone lighter. Relative to the average lifts in the men’s 93kg category (250kg squat, 175kg bench and 280kg deadlift) this translates to around 0.6% on the squat, 0.5% on the bench, and 0.4% on the deadlift.
The numbers for women are 1.0kg on the squat, and 0.6kg on the bench and 0.9kg on the deadlift, or 0.8% on a 125kg squat, 0.6% on a 87.5kg bench, and 0.6% on a 156kg deadlift (the 63kg category averages). So although women are starting from far lower baseline lifts, in general, heavier women outperform lighter women to a somewhat greater degree than heavier guys outperform their lighter counterparts.
However, these are only averages, and the law of diminishing returns operates here as it does in every other aspect of lifting. As the graph above shows, the relationship between bodyweight, bench and deadlift is vaguely linear to a point, beyond which it plateaus out pretty markedly. What the table below shows is how dramatic this effect is between light and heavy lifters, particularly in women.
|Gain per kg bodyweight (kg)||Gain on average lift for category (%)||Gain per kg bodyweight (kg)||Gain on average lift for category (%)||Gain per kg bodyweight (kg)||Gain on average lift for category (%)|
|Men 83 – 105kg||0.7kg||0.4%||1.9kg*||0.8%||1.0kg||0.4%|
|Women 57 – 72kg||0.3kg||0.4%||1.5kg||1.1%||1.4kg||0.9%|
* indicates statistical significance, i.e. that the effect of extra bodyweight in this category is almost certainly not zero. Most women’s results don’t reach significance because the sample is too small, but the trend is still pretty clear.
What the table shows for light men, an extra kilo of bodyweight relative to another lifter appears to buy you over 2kg on the bench, and almost as much on the deadlift. The 2.1kg on the bench is, obviously, worth quite a bit more to you; it translates to another 1.5% on the average bench of 140kg in those categories, but your 1.9kg on the deadlift will only give you another 0.8% on top of the 242.5kg average. These numbers are only slightly lower for light women, to whom they are worth more again: an extra kilo of bodyweight might buy a 51kg woman 2.7% on the bench, and 1.1% on the deadlift, relative to a 50kg woman.
Once you’re in a medium or heavy weight category, though, the benefits associated with being heavier drop sharply – a 106kg guy has effectively no advantage over a 105kg guy on the bench or the deadlift, and a 73kg girl has no advantage over a 72kg girl on any of the three lifts.
You might think this is just because an extra kilo is less of a gain in relative terms the heavier you are to begin with, but the differences are too substantial to be explained by that; an 83kg guy is 5% heavier than a 79kg guy, and could expect to have a 8.4kg advantage on the bench (2.1kg for each of his extra 4kg of bodyweight). An 87kg guy would be 5% heavier again than our 83kg guy, but in contrast, he could only expect an extra 2.8kg on the his bench for his trouble.
Conversely, on the squat, our 83kg gentleman would have 6kg over his 79kg mate, and their 87kg buddy could expect 7.6kg over the 83kg guy. Even on the squat, though, a 110kg guy can only expect about a 4kg advantage over a 105kg guy, for the same 5% increase in bodyweight. So a 5% increase in bodyweight buys you a 3% gain on the average squat if you’re a light guy or a medium sized guy, and a rather tragic 1.4% gain if you’re a big guy.
In general, then, it looks like bigger is a lot better if you’re small, a little better if you’re medium sized, and not much use at all if you’re already big. The exception to this is on squats, where even the big boys can expect a modest return on extra kilos. Any average-sized or large punters hoping to GOMAD themselves to fame and glory on the bench, however, might have another thing coming. This might not surprise most people, as we all know there has to be a ceiling on what human beings can lift no matter how big they are, but I was surprised at just how quickly the benefits of being heavier appear to taper off.
Having said that, this little exercise is, of course, only comparing individual lifters to each other once they’ve reached, or come near to reaching, the pinnacle of their careers. Whether an individual lifter would actually get the same advantage from putting on 10kg that someone who’s naturally around 83kg has over somebody who’s naturally around 73kg is, potentially, quite a different matter. Novices will obviously gain both strength and weight as they train, and people who decide to drop a weight category might lose more or less from their lifts than the table above suggests. If anybody has had a significant change in bodyweight after the glory days of their newbie gains, I’d be curious to hear how much you gained or lost, and what it did to each of your lifts.