Science Looks at Bodyweight as a Factor in Lifting Weight
Many Breaking Muscle readers are bodyweight exercise enthusiasts, much like myself. It’s always plain to see when comparing performances of bodyweight trainees that the lighter athletes often perform better. This makes a lot of sense because they don’t have as much weight to move, and any time you lower a load, you can perform more reps. A funny thing happens as soon as we start doing weighted lifts, though - we forget about our bodyweight.
Since bodyweight can be highly variable when compared to strength, which is what we call relative strength, coming up with an equation for how much weight to lift when training for power is much more difficult. Indeed, there has been a lot of speculation of late on why the ideal weight to use when training for power is so variable. While there are many factors involved in this equation, bodyweight is a major one that I’ve never seen considered before. In a study this month in the Journal of Strength and Conditioning, researchers finally factored bodyweight into the equation.
In the study researchers compared the results of four different groups. One lifted heavy weights of 90% of one rep max (1RM). Another lifted for maximum power without bodyweight included in their values, which amounted to 48 to 58% of 1RM. A third group lifted for maximum power, but with bodyweight included in the equations, which amounted to 20 to 37% of their 1RM. The final group was a control.
Researchers determined that including bodyweight into their equations had a substantial effect on what was determined to be the optimal external load. That is to say, when adding in bodyweight, the loads were much lower. What researchers discovered when training each group for 6 weeks was probably no surprise. Each group had some benefit in all ranges of strength and power, but the greatest benefit occurred in a range of weights that participants actually lifted in. In other words, the people lifting heavy got stronger, the people lifting a moderate amount of weight became best with moderate loads, and, you guessed it, the people training light became good with light loads.
Unfortunately, the discussion of bodyweight seems to be mostly semantic. I see no reason per se that I need to really consider bodyweight in this particular study. The researchers only used bodyweight to lighten the load, so of course this resulted in some variation, but the loads between groups were too different to be able to determine anything of substance here.
That’s not to say it’s a waste. At least it makes us begin to think about the effect of our bodyweight, particularly when training for power in which our own body may be the greatest portion of the load on even the heaviest exercises like a back squat. Since I need to overcome the force of gravity on not just the bar, but also on me, it would seem prudent to maintain the highest relative strength I can by staying lean and mean, even if my goal is pure strength and power.
1. Ilias Smilios, et. al., “Maximum Power Training Load Determination and Its Effects on Load-Power Relationship, Maximum Strength, and Vertical Jump Performance,” Journal of Strength & Conditioning Research, 27(5), 2013
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