You’ve probably been told that if you want your muscles to grow, all the exercises you do should be taken through a full range of motion (ROM).
Going from “full stretch” to “peak contraction” is necessary to stimulate the maximum amount of growth in the shortest possible time. Anything less is cheating, and you might as well just not bother.
Is a Full Range of Motion Necessary on Every Exercise?
That depends a lot on you and how you’re built. Not everyone is put together in the same way, and a ROM that’s suitable for one person may not be such a good fit for someone else.
In fact, you may very well be better off using “partial reps” on certain exercises.
Let me explain why.
Bench Press Range of Motion
Consider the example of two different lifters – Mr Long Arms and Mr Short Arms – performing the bench press. Both lifters start with their arms straight. They lower the barbell so that it touches their chest before returning it to the start position.
Mr Long Arms and Mr Short Arms have both performed the bench press through what most people would consider a full ROM. But there are some important differences.
Firstly, Mr Short Arms has done less work than his long-armed counterpart.
The amount of work performed during a given exercise is normally calculated by multiplying the amount of weight on the bar by the number of sets by the number reps (weight x sets x reps).
So if you were to bench press 200 pounds for 2 sets of 10 repetitions, the total amount of work done is 4000 pounds (200 x 2 x 10 = 4000).
But measuring work in this way doesn’t tell the whole story. Why not? Because it doesn’t include the distance traveled by the bar.
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In other words, Mr Long Arms does more work during each rep because he has to push the bar further.
Next, think about what’s happening to your shoulders.
If you have long arms and a small rib cage, bringing the bar all the way down to your chest means that your shoulders have to go a lot deeper into extension than someone with short arms and a large rib cage.
This can be very hard on your shoulders. Done often enough with a heavy weight, it could lead to a rotator cuff injury that keeps you out of the gym for some time. At the very least, you might find it impossible to perform the bench press without pain in your shoulders.
Mr Long Arms may be better served by using a shoulder saver pad. This is a pad that’s attached to a barbell, and shaves a few inches off the bottom of the movement, preventing his shoulders from going too far into extension.
He could also try the decline bench press or even the floor press, both of which involve a much shorter ROM than the flat bench press.
Cheating? Not really.
By shortening the distance that the bar needs to travel, he’s simply matching the ROM of the lifter with the shorter arms.
Deadlift Range of Motion
Let’s take both lifters and look at what happens during the deadlift.
Both start with a loaded barbell on the floor and go all the way up to a standing position. Once again, even though they’ve both performed the same exercise using what appears to be the same ROM, there are a few key differences.
This time, Mr Long Arms is the one doing less work. That’s because he doesn’t need to bend down as far to pick up the bar.
What’s more, Mr Short Arms will find it a lot harder to deadlift from the floor without rounding his back. While this is no guarantee that he’s going to end up with a back injury, it does shift the benefit-to-risk ratio of the exercise in the wrong direction.
Unless he’s training for an event that requires him to lift with a rounded back (and assuming that mobility isn’t a limiting factor), Mr Short Arms would be better off raising the starting position of the barbell with the use of blocks or a rack. This allows him to maintain normal spinal curvature at the bottom of the exercise.
Again, this doesn’t mean that he’s cheating. He’s simply modifying the exercise so that it’s a better fit for his body.
“A bar loaded with standard 45 pound plates is 8.75 inches off the floor because the original manufacturers wanted there to be enough room that if a lifter doing Olympic lifting fell with the bar overhead that the plates would be tall enough so that his head would not be crushed,” explains strength and conditioning specialist Elsbeth Vaino.
“Of the big three lifts, the deadlift is the only one where the range of motion is determined by a manufacturing decision instead of by individual anatomy. This means that everyone, whether they’re five feet tall or seven feet tall, has to pull from a height of 8.75 inches.”
The length of your arms is just one of many factors dictating what is a safe and effective ROM in any given exercise. But individual anatomical variations mean that you need to be flexible about the ROM that you use.
You may not be built in a way that lets you deadlift from the floor, squat below parallel with a heavy weight resting on your shoulders or bench press through a full ROM without setting yourself up for injury.
Full vs Partial Range of Motion for Hypertrophy
There have been a number of studies over the years to compare partial with full ROM training. With few exceptions , most studies show that full ROM delivers superior gains in both size and strength [1, 3].
However, these studies have used a partial ROM that is only 25-50% of a full ROM. They don’t compare a full ROM with an “almost full” ROM.
What’s more, certain exercises seem to be more effective at fatiguing the target muscle when they’re performed using a slightly reduced range of motion. In some cases, working in the middle range of motion and “keeping the muscle under tension” may work better than training through a full range of motion.
In one study, researchers found that the skull crusher exercise, performed only through the middle range of motion, delivered faster muscle growth than the same exercise done through a full range of motion .
Although the full ROM group saw the best results (an increase of 9.7% in the full ROM group versus 7.9% in the partial ROM group), the difference between groups wasn’t enough to reach statistical significance.
So, what’s the bottom line? Is a full range of motion necessary on every exercise?
You don’t have to use a full range of motion on all exercises, all of the time. It’s far better to modify an exercise so that you stop an inch or two short of a full ROM than to use 100% ROM all of the time and end up injured because of it.
For example, I find that shaving an inch or so off the top and bottom of rows and pulldowns is a lot more “elbow friendly” than trying to do the same exercises through a full ROM.
This doesn’t mean that you’re cheating. You’re just making intelligent training decisions designed to reduce the risk of injury and keep your joints healthy.
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