Partial Reps May Be the Ultimate Key to Building the Muscle You Want

The general mentality of any true gym rat is to give 100% when lifting weights. That means doing as many sets and reps as possible, with as high of a load as you can handle. What many don’t realize is that sometimes, less is more.

At least that’s the case with partial reps, which entail limiting your range of motion to only perform a segment rather than the whole movement. A partial rep can entail doing only half, three quarters, or even a quarter of a rep — for example, only doing the bottom half of a hammer curl. And yes, before you even ask, there are some serious advantages to this strategy.

“Partial reps have a huge value in the strength and bodybuilding world because they can help someone build strength and size in certain muscle groups that they wouldn’t normally be able to target by using the full range of motion,” explains Jack Craig, certified personal trainer at Inside Bodybuilding.

RELATED: How to Break Through a Weight Loss Plateau

Of course, partial reps aren’t for everyone. But if you’re ready and eager to shake up your strength training, this approach could very well be the secret to busting through that fitness plateau.

Here’s what to know about the pros and cons of partial reps, along with ways to incorporate them into your workout routine.

Benefits of Partial Reps in Your Workout

Lift Heavier

Since you’re only performing an abbreviated version of the exercise with partial reps, you can lift much heavier weights and create more mechanical tension. “You can use a weight that might only get you 1-3 full reps, and instead get 8-12 partial reps,” explains Craig.

Research has shown that can translate to some major muscle gains over time. 

Increased Time Under Tension

Some types of partial reps can increase time under tension — for example, doing the bottom half of a squat or a lat pull-down — because the muscle cannot rest when you don’t complete the range of motion.

“Keeping muscles under constant tension leads to greater metabolite production, which could elicit a more significant response in terms of muscle development,” explains Jack McNamara, M.Sc., C.S.C.S., of TrainFitness.

According to Dr. Nicholas Rolnick, MS, CSCS, doctor of physical therapy and certified strength and conditioning specialist, partial reps may be especially advantageous in certain regions of the quads.

“Performing repeated partial repetitions in the stretched position to 45-50 degrees of knee bending can produce more tension on the quadriceps throughout each repetition than going through the full range of motion,” he says. “This may lead to better growth of the quads.”

Increased Number of Reps

Some research has shown that it's volume, not intensity or weight, that's the real key to greater muscle gains. And fortunately, since you’re only doing a certain portion of the exercise with partial reps, you may find that you’re able to crank out more reps than you would if you were doing the full range of motion.

“Volume is the most efficient method of hypertrophy or muscle growth,” explains Blaise Collins, PhD, exercise physiologist and owner at Valkyria Wellness. 

This aspect can be super helpful toward the end of a workout. You could finish a particular exercise with a set of higher reps and lower weights, for instance, when a muscle starts approaching fatigue.

Build Muscle Even When Dealing With an Injury

Just getting back to the gym following an injury? Partial reps offer a phenomenal way to ease back into strength training. “By performing partial reps, you find ranges of motion that don’t cause pain, but still allow you to train hard,” explains Chris Cooper, founder of Cooper Training. 

For example, Cooper notes that someone who experiences knee pain with a full squat may have an easier time only doing the top half of this movement. 

Partial reps also help with mobility issues such as tight hips or ankle mobility, says Keith Lawrence, certified personal trainer at Rumble Boxing. “It’s better to do a partial rep than to put pressure on weak joints,” he tells AskMen.

Not only that, but working within a pain-free range of motion can promote faster recovery. 

“Rather than neglecting all movement and waiting for an injury to recover before fully engaging in any movement, partial reps can allow synovial fluid to 'bathe' the joint, promote increased blood flow to the area, and speed up recovery,” explains McNamara. 

Overcoming Those Sticking Points

Typically, partial reps are performed in areas of weakness (also known as sticking points), such as the bottom half of a bench press.

For example, FORM personal trainer and instructor Nathan Fletcher notes that most people are stronger on the way up from a squat than when paused at the bottom. As a result, weakness in part of the movement may prevent you from increasing the amount of weight lifted. Partial reps can help improve the weak point of a lift and help you to blast through those sticking points.

“By using these small ranges of motion you can crank out more reps that will eventually increase your overall strength and move onto a new plateau in your training,” adds Lawrence.

Improved Form

Any personal trainer will tell you that form is the most important thing for a safe and effective strength workout. As you could've guessed, it's partial reps that have an advantage here.

“Partial reps help drill certain parts of a movement so you can perfect them,” says Craig. “For example, rack-pulls are a deadlift variation that might be considered a partial rep. This motion drills the end of a deadlift, the extension of the back and knees, under heavy load so that you can become proficient in it so that when you’re doing a heavy deadlift in a competition, you’re adequately prepared to perform well.”

Potential Drawbacks of Partial Reps

While there are many perks to partial reps, there are also some potential downsides as well. At the risk of stating the obvious: you’re not working the muscle through its full range of motion. That means that while partials are great for building muscle, they’re probably not as effective as full reps when it comes to building strength. 

This disadvantage really comes into play with compound lifts. For example, Collins points out that half squats overemphasize quad development at the expense of glute and hamstring development, which could lead to muscle imbalance.

“When we eliminate part of the range, we limit the full function of multiple muscles articulating multiple joints,” explains McNamara.

Not to mention, partial reps can be extremely tiring due to the build-up of metabolites like lactic acid and hydrogen ions. As a result, Fletcher says muscles may become fatigued more quickly in subsequent sets, reducing the number of reps you can perform.

“In general, as long as partial repetitions are performed in conjunction with full range of motion ones, there are no real significant drawbacks to this technique,” Rolnick tells AskMen. “However if you are only training with partial range of motion, understand that the body will only become stronger in that particular region.”

How to Incorporate Partial Reps in Your Workout

Partial reps are typically recommended for single-joint exercises over compound movements, especially for those who are less experienced with strength training, or those looking to facilitate muscle growth.

Lawrence and McNamara say some of the single-joint exercises that are well suited to partial reps include:

• Bicep curl
• Skull crushers
• Lateral raises
• Bench press
• Barbell squat
• Barbell deadlift (Romanian deadlift)
• Split squat

“These single-joint exercises will help keep the muscle under the most mechanical tension, restrict blood flow, and potentially lead to greater metabolite build-up, promoting hypertrophy,” adds McNamara.

That said, a 2016 study published in Human Movement found that partial reps may improve athletic sprint performance and jumping in a way that full range of motion exercises don’t. 

Ultimately, experts say partial reps shouldn’t be your only training focus, but rather a supplement in the first or last quarter of your workout.

“At the beginning of the training session, partials are used to work on weaknesses/sticking points in multi-joint exercises, and at the end of the exercise session, they’re used to significantly fatigue a single-joint movement,” explains Rolnick. 

Here are some other ways to incorporate partial reps into your workout routine, as shared by Kawan Karadaghi, a certified personal trainer and owner at Anytime Fitness, and Rolnick:

• Find sticking points of a particular lift (beginning, middle, end) and correct them by practicing partial reps to become stronger in this range of motion.

• Correct sticking points of big lifts such as deadlifts, bench presses, and squats by using a weight that is about 65-75% of your one-rep max.

• Aim to complete full repetitions for 90-95% of your workouts, then do partial reps for the remainder to increase time under tension and push past muscular fatigue. 

Partial reps are an advanced training technique, meaning that if you’re not performing them correctly, you could hinder your results (or put yourself at a higher risk of injury). That’s why it’s always recommended to try this technique under the supervision of a certified professional trainer first before attempting it on your own.

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