Raise your hand if you’ve ever seen someone doing a “squat” that amounts to a quarter of a rep and you shook your head at him or her. Without seeing you, I’m going to guess that pretty much every reader of Breaking Muscle has had this experience. If you’re going to do something at all, you might as well do it right.
But as we have seen, science doesn’t always agree with our common sense, so it’s worth studying. In fact, in this case, it might make some sense. There is value to doing isometrics and full-range isotonics, so perhaps partial range work has some merit. Indeed, many successful athletes regularly employ partial range work. The board press is a great example, regularly performed by powerlifters. In a recent study in the Journal of Strength and Conditioning, researchers sought to explain where we would draw the line on range of motion.
The study was 12 weeks long, and during that time the participants did leg work 3 days per week. One group did their leg work from 0 to 50 degrees, where the other did the same work from 0 to 90 degrees. The work out was pretty rugged with various forms of squats and other leg exercises taking place on all 3 days.
As it turns out, our common sense is correct. After the 12 weeks the strength and size of the muscle was greater in the group with the longer range of motion. Researchers also measured fat stores within the affected muscle and they were reduced more in the group with the longer range of motion.
Pretty cut and dry, but wait, there’s more. The clever critic will point out that shorter ranges of motion allow for greater loads, and perhaps that could actually make them superior. The researchers anticipated this, though, and those results where the shorter range of motion performed poorly did utilize heavier weights. In fact, the shorter range of motion group used 10-25% greater weight than the longer-range group and still didn’t do as well in the end results.
It doesn’t end there either. The researchers analyzed the internal loading directly on the muscle itself. As biomechanics change throughout a single rep of an exercise, so does the internal load, even when the weight you’re lifting doesn’t change. Well it’s good researchers did this because they discovered that the load on the muscle in the longer range of motion was actually greater even though participants were lifting less weight. You didn’t read that wrong. Less weight and greater load. Given the results it makes sense, but now you know why.
I’d like to see a study in which an actual full range of motion is examined. 90 degrees isn’t exactly ass-to-grass squatting. Do the results continue as the range of motion goes further? The greatest intensity would be at about 90 degrees theoretically, so perhaps the results would be less.
For those of us who raised our hands at the start of this article, we have an even greater reason to scoff than we thought. It’s not just common sense. We should strive for good form and full range of motion in our exercises for the best results.
1. Gerard Eugene McMahon, et. al., “Impact of range-of-motion during ecologically valid resistance training 2 protocols, on muscle size, subcutaneous fat and strength,” Journal of Strength and Conditioning, DOI: 10.1519/JSC.0b013e318297143a
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