Why Do Bodybuilders Do Partial Reps?


Everyone is taught that using a full range of motion is the best way to build muscle mass. This makes perfect sense. After all, using a full range of motion is the only way to get a maximum stretch and contraction on every rep.

But if that’s true then why do so many advanced bodybuilders use partial range of motion reps on almost all of their sets?

Just take a look at the following video of Ronnie Coleman bench pressing 500 pounds:

Ronnie Coleman is using a partial range of motion on every rep!

A lot of bodybuilders use partial range of motion reps when they train their chest. However, Ronnie trains most of his body parts this way!

A lot of “experts” believe that Ronnie Coleman and other advanced bodybuilders use terrible technique on most exercises. These “experts” are DEAD WRONG!

If you are an advanced bodybuilder then partial range of motion reps are one of the best strategies that you can use to continue building muscle.

In this comprehensive guide I will teach you why bodybuilders use partial reps in their training. I will also teach you some of the best partial range of motion strategies that you can use to blast through hypertrophy plateaus.

When an advanced bodybuilder uses a partial range of motion they are almost always performing partial reps in the stretched position of the exercise. In other words they are performing reps in the bottom-half of an exercise where the muscle is really stretched out.

Just take a look at Ronnie performing seated dumbbell overhead tricep extensions:

Ronnie barely lifts the weight halfway up before dropping back down into the stretched position!

When Ronnie performs reps this way his triceps are under a deep loaded stretch during the entire set. If Ronnie were to use a full range of motion then his triceps would be under a loaded stretch only about half of the time.

Many advanced bodybuilders like Ronnie Coleman have figured out on their own that the stretched position of an exercise is where you build the most muscle mass. This may sound like “bro-science” but there is a ton of evidence showing that loaded stretches are one of the best ways to build muscle.

For example:

The Six Benefits Of Loaded Stretches

  • Loaded stretches stimulate mTOR, the “on” switch for protein synthesis
  • Loaded stretches overload your fast-twitch muscle fibers
  • Loaded stretches increase blood flow and induce hyperemia in your muscles
  • Loaded stretches release anabolic hormones into your muscles
  • Loaded stretches **potentially** stretch out the fascia surrounding your muscles
  • Loaded stretches **potentially** stimulate hyperplasia in your muscles

I won’t bore you too much with the science here. I talk about the science of loaded stretches a lot more in my article “Loaded Stretches: The Ultimate Guide!

The bottom line is there is a TON of research supporting loaded stretching for building muscle mass. And advanced bodybuilders use partial reps to build muscle mass because they mimic loaded stretches and have similar effects in terms of muscle growth.

Ronnie Coleman and other advanced bodybuilders use partial reps on 4 main muscle groups:

  • Chest
  • Shoulders
  • Triceps
  • Quadriceps

Ronnie Coleman and most other bodybuilders train the other muscle groups like back, biceps and hamstrings with a full range of motion. This includes a full stretch in the bottom position and a full contraction in the top position.

Now let’s talk about some of the best strategies for using partial reps for each of these body parts.

Partial Reps For Chest

The chest is one of those body parts that really responds well to partial reps for building muscle mass. This is especially true if you are more of an intermediate or advanced bodybuilder.

Just take a look at IFBB professional bodybuilder Stan Efferding using partial reps on the incline dumbbell press:

If you have a good sense of humor then listen to Marc Bell’s commentary:

“Look at, that not one rep locked out. Leave it to a bodybuilder to lift like a slob! Look at that – I wouldn’t count one of those. Red light on every single one! I don’t know that that is about the bodybuilders, why they do that? Maybe that’s why I’m not ripped!”

Why is Stan training this way? The chest is most strongly activated during the bottom half of pressing movements like incline dumbbell presses and incline barbell presses. Towards the top half of the movement the triceps really start to take over.

Stan wants to keep his chest under constant time under tension throughout the whole movement. In order to do this he has to train through the bottom half of the movement. Even when you use partial reps like this it’s absolutely critical that you keep your upper body positioned correctly.

The optimal mechanical position for chest exercises is with your sternum held high and your shoulder blades squeezed back together. This will place your chest under the biggest stretch possible throughout the whole movement.

Just watch IFBB pro John Meadows performing stretch push ups:

John keeps his sternum as high as possible and his shoulder blades squeezed together throughout the entire movement. He even does this towards the mid-range of the exercise! This is a great strategy to use to blast through chest size plateaus.

Partial Reps For Shoulders

A lot of bodybuilders like Ronnie Coleman perform partial reps on overhead presses to overload their delts. For example:

Why do advanced bodybuilders train this way? In order to answer that question you have to think about the function of the delts.

One of the main functions of the deltoids is to help you press your arm over your head. However, the shoulders are mostly active in the bottom half of this movement until your upper arm is parallel with the ground. Once your upper arm is parallel with the ground your traps, triceps and serratus anterior really take over the movement.

Ronnie Coleman wants to make sure that his shoulders are under constant time under tension throughout the whole set. And the only way to do that is to press with a partial range of motion.

Of course there are other ways to use partial reps to build huge delts. Here is John Meadows demonstrating partial reps on the rear delt fly:

The main benefit of this exercise is you can overload the bottom half of the range of motion with a very heavy weight.

According to John you can use over twice as much weight with this abbreviated range of motion as you can with a full range of motion set!

I’m not saying that you should perform all of your sets this way. However, for an advanced bodybuilder this can be an awesome strategy to overload the rear delts.

Partial Reps For Triceps

The triceps are a tricky muscle group to use partial reps with. During compound pressing exercises like the close grip bench press the triceps are most active during the top half of the movement.

Performing partial reps on the bench press to train your triceps would make no sense because that would turn it into a chest exercise!

A much better strategy is to perform partial reps on various triceps isolation exercises like extension movements. This is a strategy that Ronnie Coleman and many other bodybuilders use.

Just take a look at Ronnie performing partials on skull crushers:

He’s barely lifting the weight halfway up before returning to the stretched position!

If you think that Ronnie would have gotten better results using a full range of motion then you have to be kidding yourself. Ronnie had 23.5 inch arms at his peak!

Partial Reps For Quads

The quadriceps are another one of those muscle groups where advanced bodybuilders love to use partial reps. Just take a look at Ronnie Coleman using partial reps on hack squats:

OK, I want you to think about how hard hack squats are in different parts of the movement. Machine hack squats are very difficult in the bottom and mid-range portions of the exercise.

When you get to the top of the exercise they become way easier because your knees start to lock out and you lose tension on your quads.

Some bodybuilders like John Meadows will use bands and chains to make the top part of hack squats just as hard as the bottom part. Ronnie’s strategy is different: he just skips the top part of the movement to make sure his quads are working hard the entire time!

Ronnie uses this strategy on almost all major quad movements including front squats, back squats, leg presses and hack squats.

Partial Reps For Back, Biceps And Hamstrings

I mentioned earlier that advanced bodybuilders mostly use partial reps to train their chest, shoulders, triceps and quads. This is true. However, there are ways to use partial reps to train your back, biceps and hamstrings.

One of the most popular methods among advanced bodybuilders is to use post-failure partial reps. The idea is simple: you train to failure on an exercise and then perform partial reps out of the stretched position when you can’t perform any more full range of motion reps.

Here is John Meadows demonstrating the post-failure partial rep technique on lying leg curls:

Talk about a brutal set! John actually performed a double drop set plus partial reps at the end. His set looked like this:

  • Perform 15 reps, drop the weight, no rest
  • Perform 10 reps, drop the weight, no rest
  • Perform 8 reps, increase the weight, no rest
  • Perform 25 partial reps in the stretched position, done!

That’s 58 total reps! What a madman! This kind of post-failure partial rep strategy can be used on all kinds of hamstring, back and bicep exercises. The bodybuilding coach Dante Trudel used to have his trainees use post-failure partial reps on rack chins.

The first-ever Mr. Olympia winner Larry Scott was also a big fan of post-failure partial reps. He used to perform post-failure partials on the preacher curl station to build up his legendary 20-inch biceps in the 1960s.

Here was Larry’s favourite bicep routine:

Larry Scott Partial Reps Bicep Workout

  • A1: Bilateral dumbbell preacher curls (supinated grip), 3 x 6**, 2/0/X/0, 10 seconds rest
  • A2: Preacher ez-bar curls (wide / supinated grip), 3 x 6**, 2/0/X/0, 10 seconds rest
  • A3: Preacher ez-bar curls (wide / pronated grip), 3 x 6**, 2/0/X/0, 180 seconds rest

**Perform 6 full range of motion reps followed by 4 partial range of motion reps in the bottom position. Larry calls these partial reps “burns.” You’ll know why after you try them!

As you can see advanced bodybuilders also use partial reps on back, bicep and hamstrings exercises. The main difference is they are used as a post-failure training strategy rather than being used on every single rep of the set.

Conclusion

Advanced bodybuilders have been using partial reps sense at least the 1960s and they will continue to be used for as long as people are pumping iron.

Internet experts love to say that guys like Ronnie Coleman lift with “terrible form” and would be much better bodybuilders if they trained with a full range of motion.

Real-world experience and the scientific literature has shown that these experts are wrong and that the advanced bodybuilders were right all along.

I’m not saying that you should use partial reps on every set or that they are better in every situation. Dorian Yates trained through a full range of motion on every set and he seemed to build plenty of muscle without partials.

However, if you are a advanced bodybuilder then they are a great strategy to experiment with. They work especially well when training the chest, triceps and quadriceps and can help take your physique to the next level.

“The greatest thing is when you do put your heart and soul into something over an extended period of time, and it is worth it.”

Thank you for reading and I wish you the best of luck on your strength training journey!

Dr. Mike Jansen

I am the creator and owner of Revolutionary Program Design. I help advanced athletes take their training to the next level and achieve results they never imagined possible.

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