Range of motion. Everyone tells you you must use a full range of motion when you train. It seems obvious, but much research has produced information that begs the question; do you need to use full ROM? There’s been a lot of talk lately about using things like partial reps and eccentric training; neither uses a complete range of motion, so what gives? So here’s the deal. There is a lot of very new research on the range of motion that has produced varying results. However, many “influencers” have taken this to make pretty bold statements and confuse things more than it needs to be. Luckily, the application will be pretty simple once you sift through everything so we’re going to explain how to use range of motion in your training to maximize your gains.
What Is Range Of Motion?
In its simplest definition, range of motion is how far you can move a joint through flexion and extension. Regarding weight training, range of motion also refers to the distance a joint moves during a single rep. Basically, it’s the movement of a joint during an exercise.
Before we get into the movements, we need to review the two major muscle contractions, eccentric and concentric, and how they relate to range of motion. Understanding these, and what’s happening to the muscle, is crucial to understanding why partial reps might be good.
Concentric & Eccentric Contraction
Your muscles are not one solid piece of meat. Rather, they are composed of a bunch of muscle fibers that are intertwined together. Think about how rope is formed.
These muscles are connected to our bones at various sites and cross at least one joint. The origin of a muscle is the site on the bone that does not move, acting like the foundation. The muscle then travels down the bone, crosses a joint, and “inserts” in the bone, creating the insertion. The insertion is the part of the muscle that is pulled.
For example, the biceps origin is actually connected to the scapula. It then runs down the humerus (arm bone), crosses the elbow joint, and is inserted into the upper forearm. When the biceps contract, the origin (on the scapula) doesn’t move. Rather, the muscle contracts and flexes the elbow by pulling the forearm up.
So, let’s look at the contraction in more detail (but not too much!)
Concentric Contraction
Above, we talked about the muscle fibers that make up a muscle. Each muscle fiber comprises smaller units known as sarcomeres, which are backed up to each other down the entire muscle. Then, each sarcomere contains contractile units that overlap: myosin and actin. The best way to think about this is a bunch of rubber bands connected to each other.
When a muscle contracts, the myosin and actin begin to pull on each other, ultimately shortening the muscle. This will pull the bone, which is known as concentric contraction. Examples are;
The biceps, when the elbow flexes during a curl
The triceps, when the elbow extends during an extension
Eccentric Contraction
At the same time, the myosin and actin back off, ultimately lengthening the muscle and letting the bone “lower”. This is called the eccentric contraction. Examples are just the opposite of the above.
The biceps, when the elbow extends during an extension
The triceps, when the elbow flexes during a curl
When we speak below about “lengthened partials”, this is what it’s talking about. This is the part of the repetition when those muscle fibers are extended.
Full Range Of Motion
Now that we understand concentric and eccentric and how the muscle lengthens, we can discuss a range of motion. When we perform a rep with a full range of motion, we are talking about a joint going from full extension to the endpoint of flexion. Of these, the endpoint of flexion will vary the most among individuals for various reasons.
On the other hand, full extension is pretty much the same for everybody. Some exercises can vary slightly. For example, lifters are instructed to keep soft knees at the top on movements like the leg press rather than locking out the knees.
At the same time, the start and stop points for the various exercises will differ depending on if you’re training a flexor or extensor.
Flexors: Start at extension and end at flexion (biceps curls, leg curls)
Extensors: Start at flexion and end at extension (leg extensions, triceps pushdown)
In both of these, the working muscle is lengthened at the beginning of the movement. For example, during a leg extension, the exercise begins with the knee flexed. This occurs as the quad is lengthened, and then when it contracts, the muscle shortens and pulls the leg up.
The opposite occurs with a bicep curl. The exercise begins with the arms extended, which lengthens the biceps. Then, when the muscle contracts and shortens, it pulls the muscle up.
We’ll use the back squat to illustrate various ranges of motion:
Half Rep & Partial Rep
Apart from the full range of motion, you have half reps or partial reps.
Initial partial: The initial partial is the first half of an exercise when the muscle is lengthened. These will also be referred to as “lengthened partials” as this occurs at the bottom half of the eccentric contraction and top half of the concentric when those muscle fibers are extended. There is no specific range of motion for these, but it is regarded to be far from theory of the movement to halfway.
Final partial: The final partial would be from the halfway point to the finish. This is when the muscle is in a shortened position and generally starts at the halfway waymark to the top of the concentric.
The term “half reps” is a bit more nuanced but generally refers to the first half of a movement or simply to not moving through the full range of motion. For the rest of the article, we won’t be referring to this term.
Do You Need To Use Full Range Of Motion?
How often have you heard things like “Half-rapper!” or “And not a single rep performed!”
Both of these are pretty common sayings when someone is slacking on their reps. However, these sayings assume that doing full reps is needed. As you can imagine, it’s nuanced.
However, what’s not nuanced is that you should be using the full range of motion! The real question we should be asking is: Do you always need to use the full range of motion?
With that said, we’re going to go over why full range of motion is a good thing.
Improve Flexibility And Mobility
Did you know that studies have shown that using free weights with full range of motion is a highly effective means to increase flexibility and mobility? It does, and it makes sense.
When you perform a weighted squat, you descend under load while flexing the hips, knees, and even ankles. In fact, any coach who has worked with the general public will tell you that many people are unable to squat parallel when they first begin!
We could also discuss lunges, overhead presses, and bench presses. All of these are great for keeping joints mobile but require a full range of motion¹.
Improve Joint Health
While using full range of motion improves mobility, part of this is increasing the strength and function of your joints. The joint is a highly complex structure with tendons, ligaments, muscles, and synovial fluid—a lot is going on.
In fact, range of motion is talking about the movement in joints! Therefore, in order to maintain the optimal function of your joints, using the full range of motion is a must.
Required For Beginners
If you’re a beginner, using the full range of motion shouldn’t be a question. We’ll discuss possible benefits of partial range of motion below but those are for lifters with experience. When you start lifting, your muscles are a blank slate, and you have no experience moving a heavy load. Therefore, if you start your career with partials, your muscle will perform a full range of motion with a load!
Even if you want to say you’ll only use partials sometimes, we still believe new lifters need to stick to full reps. The muscles have a lot of room to grow and as we mentioned, there are other issues to be concerned with other than just optimizing muscle growth. This is in line with our belief that beginners should stick to the basics.
They Work!
Let’s be clear. The full range of motion works! Lifters have been building muscle and strength forever using the full range of motion and we must keep this in mind as we talk about using partials below. The question isn’t whether using full range of motion builds muscle because we know it does. What people are asking is if partial reps are better.
Full Range Of Motion For Strength
Another crucial aspect concerning the range of motion is strength adaptations. Strength improves the neuromuscular system through different adaptations from muscle growth. Therefore, it responds differently to different stimuli. This is important as most of the talks about partials deal with muscle growth.
One important aspect is that strength seems to be site-specific. This means a muscle only increases in strength at the length a load has been placed on it. For example, if you only train a muscle in the first half of a rep, adaptations to the second half would be mitigated. Therefore, as a general rule, you should train the full range of motion for strength².
However, we will look at some times when partial reps can be advantageous for strength.
Partial Reps For Muscle Growth
So now, let’s get into partial reps. One of the catalysts for the rise in interest in partials is pretty fascinating: stretch-mediated hypertrophy. Stretch-mediated hypertrophy is a phenomenon in which a muscle sees greater muscle growth when it is in a position of greater stretch, such as the triceps during an overhead extension.
This also implies that the initial portion of a rep would have a greater effect on muscle growth than the final partial due to it being in a lengthened state. This is why we went over this above!
However, that doesn’t mean that just performing the bottom rep is more effective than performing the full range of motion, does it?
Well, actually…this is where things get interesting!
In 2022, researchers had three groups of subjects perform leg extensions with three different range of motions³:
1st Half of ROM (initial)
2nd half of ROM (final)
Full range of motion
At the end of the study, the researchers found that the initial partial group saw greater muscle growth in the quadriceps than the other groups. To be clear, performing partial reps in the lengthened state produced more growth than the full range of motion.
And this isn’t a stand-alone study. Another similar study was performed in 2023 comparing the growth of the calf muscle using various ranges of motion during calf raises⁴. Again, they found that the initial part of the rep produced significantly more muscle growth +15.2% in the medial gastrocnemius (inside calf muscle) compared to using full ROM (+6.7%) or final partial (+3.4%)
When it comes to the lateral gastrocnemius, the initial ROM still had greater growth but not to the same degree (INITIAL ROM = +14.9% vs. FULL ROM = +7.3% Vs. FINAL ROM +6.2%).
But there’s more! Another study had similar results when training the triceps with either the initial half rep or the full range of motion. Again, the initial rep led to greater growth⁵!
Now, this seems like a closed case. However, when we look closer at the exercises that produce greater muscle hypertrophy, we see they’re all isolation exercises. Further, you notice that the studies utilize single-exercise protocols.
Well, newer research has tried to answer that.
Full ROM Vs. Partial ROM Training Programs
This research is just a few days old at the time of writing this article⁶. In fact, we had to edit and input the findings, which just goes to show you how new this phenomenon is.
Dr. Brad Schoenfeld and his team had 2 groups of trainees complete similar full-body training programs that contained compound and isolation exercises. The major difference is that one group always performed a full range of motion while the second group only performed partial reps in the lengthened state.
The trainees followed their program for 8 weeks, and at the end, studies reported that both groups showed similar gains in muscle growth and strength endurance. However, the results did favor the full range of motion.
One other factor to consider is that each group trained each set to failure, meaning the partial reps probably performed more reps (the study doesn’t say so). So, they possibly performed more reps but saw similar increases in strength. At this point, we do want to point out that in the triceps study above, they actually equated the number of reps so that wasn’t a variable.
This study does show the power of lengthened partials, but at best, we can say that you should be sure not to skip the lengthened portion in a full body program. But it does raise more questions that’ll be discussed below.
Partial Reps For Strength
So now, let’s look at using partials for strength. Again, these should be used by intermediate and advanced lifters. The primary time lifters use partials for strength is to train a sticking point or work a specific part of a movement. In this context, partial reps are used by setting up the exercise so the load starts at different heights.
For example:
Board presses (placing a block on your chest during the bench press) are very popular for powerlifters to train this mid-range or lockout.
Pin presses
Floor presses
Rack pulls or block pulls.
Some elite lifters even claim they use partials more than normal range of motion. At the same time, they may even use a greater range of motion (e.g., deficit deadlift). The main point here is that there are other ranges of motions you can use that are effective at increasing strength.
To work on a sticking point, the common advice is to place the bar an inch or so below the spot you have issues with. For example, many people have a sticking point about the halfway mark on the bench press. Therefore, you would place the bar just under the halfway mark.
Now, we do want to mention using partials during the eccentric portion of some compound movements when the person stops on their own. For example, rather than coming down to a block on bench press or a box to squat from, a lifter may simply come down 25% of the way and then stop.
Many people have reported that doing this actually causes discomfort in their joints and some studies have even suggested that this can increase the torque and pressure⁷. Therefore, we wouldn’t suggest this method. If you use a partial rep with big compound movements, we like to use some sort of block to come down during the eccentric or start with the concentric.
Now, if you do want to use partials without a block, we recommend doing it during the lengthened portion. For example, on the bench press or squat, begin by coming down 100%. You could then come up 25-50%, go back down, and come back up. These are often known as 1 and ½ or 1 and ¼ reps. Pulse squats are a great example of this in which numerous partials are performed. However, these work better with moderate loads.
Unanswered Questions With Range Of Motion
Upon first looking at the studies that favor partial reps, you realize quite a few support their use. The main caveat is that they only occur in the lengthened state.
However, while this shows us that partial reps can be advantageous, there are quite a few questions that remain:
How much can you use in a single session before you get diminishing returns?
Does adding partials in the lengthened state still add growth if you hit your muscle’s maximum recoverable volume?
Should you use parietal reps on every exercise? On every set?
As you see, quite a few questions remain unanswered. Remember that most studies causing so much noise in the fitness world used just one exercise. Now that we have a full program, it shows us that performing the lengthened portion of a rep can only produce similar gains, at least in this one study.
How To Use Range Of Motion In Your Training
So, what do we do with all this information? Well, we at Set For Set don’t like to overcomplicate training. You could continue using a full range of motion for all your exercises.
Using the full range of motion obviously eliminates any possible issues, such as affecting the strength of your ligaments, causing discomfort, or even possibly missing out on gains. This is especially true for beginner lifters. That said, you should still emphasize the lengthened part of a rep. This seems to definitely be the most important portion of a rep so put your focus here.
Now, let’s say you want to optimize your training. We still believe that most of your training should involve a full range of motion, especially your big, compound exercises. However, as we mentioned, utilizing things like block pulls and board presses definitely plays a role with experienced strength lifters.
Regarding your smaller compound exercises and isolation, we think you could experiment with partials and see how your body reacts. Here are 6 ways to implement partials for muscle growth.
1 and ¼ rep or 1 and ½ rep
These can work well for anything but are of special interest for machine-based compound exercises and lighter compound exercises. If you’re experienced and have a safety mechanism, you could use these for things like bench presses and squats.
Perform these by first moving through the entire eccentric, lengthening portion. Then, move 25-50% through the concentric and return to the fully lengthened potion. Once you hit the bottom, you’ll perform the full concentric.
Last reps to failure with partials
This could work great with smaller isolation exercises such as bicep curls. Perform the full range of motion reps until about 60-70% failure. Then, switch to only performing lengthened partials until failure.
Last set to failure with partials
Perform all sets with full range of motion except the last one. On your last set, only use lengthened partials until failure.
Slow down the lengthened lengthened portion
There are still some ways to use this information for larger movements, such as barbell squats. Theoretically, the best way to utilize the lengthened proportion is to slow down during this phase and maximize the time under tension here.
For example, perform the first half of a squat at normal speed. Once you hit halfway or so, slow down until you hit depth. Return to the halfway mark using a slower speed, then power up.
Heavy partials
Now we’re talking!
Heavy partials have actually been a staple in bodybuilding for a while. One of the best examples is the Kroc row. These dumbbell rows performed with extra heavy weight use a little body motion to force out reps, and more often than not, the reps aren’t full reps.
With that said, performing partial reps will likely allow you to use more weight. Therefore, you could experiment with some exercises by adding 10%- 15% load and then performing lengthened partials.
These would probably work really well for training the back.
Use Partials After Failure
This method is very interesting. Let’s assume that partials produce similar amounts of hypertrophy and that partials are easier to perform. Theoretically, you could use partials once you hit failure and keep going. In fact, a study recently used this method to increase muscle mass in the calf⁸!
Here’s what you do: First, perform a set using full ROM. Then, once you approach failure, switch to partials. You’re effectively performing a drop set but using parietals rather than dropping the weight.
This is one of the more intriguing methods that use partials to maximize muscle growth.
Final Verdict On Range Of Motion
A lot of cool research is being done on the range of motion in exercises. However, it gets a bit more muddled when we stop to see what the research means and how we could apply it to our training. We’ll also say that this information is very new (new research was literally put out during the original writing of this article) and our understanding could change easily.
WIth that said, your best bet is to continue using the full range of motion, emphasizing the lengthened partial. This is especially true for beginners. Experienced lifters could experiment with partials and see how their body responds. If you see more growth, keep doing it. If you don’t, then stop. That’s about as complicated as it needs to get!
References:
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