How the Length of Your Bones Affects Your Power Output
In a recent article I discussed various methods of performing a bench press. One of the take-home points was that power output was highest when lifting explosively with 55% of an athlete’s one rep max (1RM). Although that effort yielded the greatest power for the weights used in that study, the actual best weight to use for the highest power production might not be 55%.
Indeed evidence is conflicted over what percentage of 1RM actually allows the greatest expression of power. In fact, it seems that from exercise to exercise and even person to person, the best weight to use for power output is variable. A recent study in the Journal of Strength and Conditioning covered why this might be.
The researchers looked at each athlete’s anthropomorphic measures, meaning their actual unchangeable physical characteristics like arm length, and some changeable measures like arm girth. They tested each athlete, in this case rugby players, for their 1RM and then determined at which percentage of that weight each athlete could produce the most power.
What they determined was that limb length was negatively correlated with the weight at which the greatest power was produced. That sentence was a bit heavy, so let me break it down a bit better. The biggest correlation was in upper arm length, basically your humerus - from shoulder to elbow. The longer the humerus bone, the lower the weight you need to express the greatest power. People with long humeri averaged maximal power output at about 22% of their 1RM, where people with shorter humeri expressed the most power at an average of 38%.
The same negative correlation applied to muscle size and experience. The bigger and stronger the athlete was, the less weight was needed to achieve the greatest power output.
The recommendation by the researchers is to use this information to determine what weight is appropriate for a lifter who wants to train for the development of power in the upper body. The longer limbed the person, or the bigger and stronger they are, the less weight will be necessary to accomplish this goal. It’s a bit surprising just how little weight was necessary. The average for all the athletes was right around 30%.
Now, you may have seen powerlifting protocols recommending heavier weights than this. That advice might still be good. In the study the researchers actually used a “bench throw” exercise, which was a bench exercise inside a Smith machine in which the athletes would actually release the bar, trying to launch it well above themselves. Because with a regular bench press this would not be safe, you would likely need to press a weight up as fast as possible and hang on to it at the end. As this will slightly slow the movement, a heavier weight would be required to achieve the peak power at that reduced velocity.
With this evidence, athletes interested in developing upper body power production might want to reduce their loads, or even look into alternative methods in which their weighted implement can be released. It seems these lighter loads are the best for the expression of power, and similarly are probably best for the development of power.
1. Christos K. Argus, et. al, “Assessing the variation in the load that produces maximal upper-body power,” Journal of Strength and Conditioning, DOI: 10.1519, 2013
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