Why Do Your Arms Shake When You Bench Press? (6 Reasons)

both novice and experienced lifters can experience their arms shaking when they bench press

Both novice and experienced lifters can experience their arms shaking when they bench press.  While this isn’t the worst thing that can happen when you bench press, you’ll still want to understand why it happens and what to do about it. 

So why do your arms shake when you bench press?  When your arms shake in the bench press it’s a sign of muscular fatigue. Not all of your muscle fibers fatigue at the same time though.  As some muscle fibers stop working, others are working over-time, which causes the appearance of a jerky/shaky range of motion while benching.  

However, there’s more to the story.  Muscle fatigue can be caused by a specific weakness or imbalance between muscle groups, or a lack of technique that reduces your ability to recruit your muscle fibers properly.  In this article, I’ll explain the 6 specific reasons why your arms shake when you bench press and how to fix it.

What Does It Mean When Your Arms Shake When You Bench Press?

If you’re a healthy individual with no neurological conditions (multiple sclerosis, Parkinson’s disease, stroke, etc.), then shaking while you bench press is simply a sign of muscular fatigue. 

Muscular fatigue occurs when your muscles grow tired because you’re either lifting a maximal load (i.e. attempting a 1 rep max) or you’re pushing a weight close to failure (i.e. lifting 70% of your 1 rep max for as many reps as possible).  

In order to understand why you shake as you fatigue, you need to know some basic physiology on how your brain connects with your muscles as you bench press. 

Let’s cover the basics now (if you want to skip the anatomy lesson scroll down to learn more about the 6 specific reasons your arms shake)

What’s Going On Inside The Muscle When You Shake?

a neuron is just an electrical communication link between your brain and your muscle

Once you’ve made the decision to produce an action, something called a “neuron” sends that message from your brain down to your muscles.  

A “neuron” is just an electrical communication link between your brain and your muscle. 

Each neuron connects to several muscle cells. In some cases, when it comes to your bigger muscle groups, like your pecs and triceps, one neuron can control thousands of muscle cells. 

A single neuron and the multiple muscle cells that it controls is called a “motor unit”. 

As you bench press, motor units go from a fresh state to a more fatigued stated.  Eventually, some motor units become temporarily non-functional.  In other words, they go offline, which puts pressure on the remaining motor units to pick up the slack.  

The shifting of activation from motor units that stop working to other motor units that aren’t fatigued yet will give rise to sudden jerky movements, which is why you shake.  

The Shaking Should Be Temporary

While shaking in the bench press is a sign of your motor units fatiguing, the fatigue is temporary. 

In other words, as you rack the barbell, take some rest, and do another set, your motor units should partially recover and be ready to take on more work.  

This means that the first few reps of your next set should appear to be more smooth.  That is until you get closer to your fatigue limit again, where the shaking may return. 

The cycle of challenging your motor units in this way, i.e. providing it a stimulus, reaching fatigue, and recovering and adapting, will actually get you stronger over a longer period of time.  

The result will be that you’ll be able to handle more weight, for more sets and reps, without having your arms shake as early in the workout as they did previously.  This is called “building your work capacity” where your muscles can do more work at the same or higher loads before fatiguing.

So, Is Shaking A Good Thing Then? 

Not so fast.  

Yes, fatiguing the muscle is a good thing as it’s a sign that you’re breaking the muscle fiber down, which causes the body to adapt and get stronger.  

But constantly taking your muscles to fatigue where you’re shaking every rep, set after set needs to be considered more carefully. Too much fatigue all the time can lead to overtraining.

This is why you need to look at your technique and other training factors to understand if there are any reasons why your muscles are fatiguing prematurely. 

Let’s look at those reasons now.  

6 Reasons Why Your Arms Shake While Benching

The 6 reasons why your arms shake during the bench press are: 

All of these reasons may contribute to your muscles fatiguing quicker than they normally would, which we’d want to address right away.  

1.  Forming New Neurological Connections

the only solution to raising your fatigue threshold is to continue to stimulate the muscle by bench pressing

If you’re new to bench press, or you haven’t bench pressed in a while, then your brain will be forming new neurological connections that may result in a lower fatigue threshold.

In other words, since you’re training new muscle groups, your motor units aren’t used to the stimulus yet, so fatigue will occur much faster.  This can result in your arms shaking while you bench press.  

The Solution: 

The only solution to raising your fatigue threshold is to continue to stimulate the muscle by bench pressing.  

What I would suggest is using a training load that prevents you from shaking, and try to build more sets and reps with that same load.  This would involve using a weight where you feel you’re leaving 1-2 reps left in the tank when you stop at the end of a set. 

Over several weeks, you can increase the load, but the key measure of success will be that you can handle ‘more work’ with the same (or increasing) loads before you start shaking.

Some people also like to increase their bench press frequency.  Check out my article on How Many Times Per Week Should You Bench Press if you’re interested in learning more.  

2.  Weak Stabilizer Muscle Groups

weak stabilizer muscle groups in the bench press can cause inefficient movement patterns

Weak stabilizer muscle groups in the bench press can cause inefficient movement patterns, which can look like your arms shaking under heavy weights. 

The bench press requires both big and small muscle groups to perform efficiently:  

  • The bigger muscle groups like the pecs, delts, and triceps, allow the shoulders and arms to produce force on the barbell.  
  • The smaller muscle groups (the stabilizers), such as the rotator cuff muscles and traps, help decelerate the barbell (on the way down) and restrict inefficient movement patterns, allowing the barbell to stay in the right trajectory. 

Together, the bigger muscle groups and the stabilizers are designed to work in collaboration to help produce maximum force and a well-coordinated movement. 

However, often the bigger muscle groups will get stronger at a pace faster than the stabilizing muscles. This sort of imbalance will introduce fatigue a lot quicker in the bench press, which can be represented by the arms shaking.  

Check out my article on the Muscles Used In The Bench Press, including how to change muscle activation based on grip, angle of bench press, and variation. 

The Solution

You should implement a specific routine dedicated to building up the strength of your rotator cuff and lower trap muscles.  

Here are the four exercises you should do: 

  • Band Pull Aparts

2-3 sets of 15-20 reps

  • Low Trap 3 Raise 

2-3 sets of 10-12 reps

  • Weighted Side Plank (On Elbow)

2-3 sets of 20-40 seconds per side

  • Side-Lying Dumbbell External Shoulder Rotation

2-3 sets of 15-20 reps

If you’re shaking in the bench press, you should perform this routine twice per week.  

Once you’ve noticed your shaking has decreased or been eliminated, you can drop this routine down to once per week to maintain strength and stability.

You’ll also want to make sure that you’ve properly warmed up your stabilizer muscle groups.  For that routine, check out my article on How To Warm Up For Bench Press.  

3.  Didn’t Set Your Shoulder Blades

set your shoulder blades properly prior to unracking the barbell in the bench press

If you don’t set your shoulder blades properly prior to unracking the barbell in the bench press, it can decrease your ability to recruit your stabilizing muscle groups.  This can cause your arms to shake when bench pressing.

The previous reason discussed weak stabilizer muscle groups. However, this reason refers to the fact that you might have strong stabilizers, but you’re simply not recruiting them properly. 

The most optimal position for your shoulder to be is when your scapula (shoulder blade) is pulled back and down on your rib cage.  The fancy term for this is called scapular retraction and depression. 

The goal is to get into this position prior to unracking the barbell, as it would be much harder to pull your shoulder blades down and back once you already have the load over your chest. 

The Solution

The best way to learn how to retract your shoulder blades is to practice using what’s called a “scapula push-up”

best way to learn how to retract your shoulder blades is to practice using what’s called a scapula push-up

While kneeling on all fours with straight arms, you will go through a process of pushing and rounding your shoulders forward, and then pulling and retracting them back.  

Then, the key is to replicate this while you’re bench pressing.  It might feel awkward at first, but let’s take a look at an example. 

Notice how Amanda Laurence, a World Powerlifting Champion, lifter her upper body off the bench press to pull her shoulder blades back before starting the bench press: 

You’ll want to ensure that you can hold this retracted shoulder position as you bench press  

If you can’t, and you notice that your shoulder blades start to move off the rib cage (scapular winging) or if your shoulders begin to round forward, then it’s likely because you have weak stabilizer muscle groups.  

In that case, work on some of the exercises I mentioned in the previous section (band pull aparts, low trap 3 raise, weighted side plank, and side-lying dumbbell external shoulder rotation).

4.  Weak Grip On The Barbell

a weak grip on the barbell can lead to your arms shaking

A weak grip on the barbell can lead to your arms shaking because the muscles from your wrist to your shoulder will not have any muscular tension. 

Here’s what I want you to do right now: 

  • Put your right arm out in front of you and relax your hand
  • Take your left hand and wrap it around your forearm 
  • Now squeeze your right hand as hard as you can

What do you notice?  

All of the muscles in your right forearm begin to activate.  You’ll also feel tension through your bicep and tricep.  

Getting your muscles tight in the bench press starts from the hands.  If the hands are relaxed, everything else will be relaxed. A relaxed muscle will create instability under load. 

Solution

One of the most important things you need to do prior to unracking the barbell is to get maximum tightness through your upper body. 

As such, you need to squeeze your hands as HARD as possible before you take the barbell off the rack.  

I like to cue lifters on “leaving fingerprints on the barbell”.  In other words, squeezing so hard that they’re trying to indent the barbell with their fingers.  Obviously, that’s impossible.  But that’s what they’re trying to ‘think about’ while squeezing their hands.

A secondary benefit of ensuring your hands are tight on the barbell before unracking is that the load will feel lighter in your hands.  That’s due to a little known thing called proprioception.  A topic for another time. 

I discuss more about making the weight feel lighter in your hands in my article on the Benefits of Wrist Wraps.  Scroll down to Benefit #5 to learn more about proprioception.

5.  Lacking Leg Drive

using leg drive to your advantage while bench pressing

In the world of powerlifting, the bench press is considered a full body exercise.  The legs provide a pivot point for stabilizing the torso.  If you’re lacking tension through your lower body, then when the set gets hard, you might find your arms shaking due to less overall stability.

If you don’t believe me, then why don’t you try benching with your legs up, and then using the same load, compare how it feels when benching with your feet on the floor. 

You’ll notice that your upper body works more efficiently (less hard) when your feet are on the floor because some of the stability requirements now get transferred through the ground. 

This is the concept of using leg drive to your advantage while bench pressing (click that link to read my full guide on the topic). 

The Solution

While using your lower body to increase overall stability in the bench press is an advanced technique principle, it’s something that anyone can start to implement rather easily.  

First, find a comfortable foot placement where your feet are flat on the floor.  

Then, drive “down and away from you”.  You want to drive your feet straight down into the floor, and at the same time, away from you.  

As well, you want to think about pressing into the outer part of your heel, as you can drive a bit harder into your feet when doing this. 

6.  A Shortage of Nutrients & Water

a shortage of nutrients and water can lead to premature muscular fatigue

The final reason why you might shake in the bench press is because you haven’t fueled your body through proper nutrition and hydration.  A shortage of nutrients and water can lead to premature muscular fatigue.

If you’re someone who uses an intermittent fasting diet, then you might experience muscle tremors.  This is because your muscles need to be fueled by a certain amount of glucose, especially during hard exercise.  If not, it can lead to a condition called hypoglycemia.  

The Solution

Ensure you have a high carbohydrate meal 1-2 hours prior to bench pressing.  

If you use an intermittent fasting diet, you may need to restructure the timing of your workout so that you’re lifting during your ‘feeding window’.  Only in this way, will you be able to eliminate shaking in the bench press.

Frequently Asked Questions

How Do You Stop Shaking During The Bench Press? 

You can stop shaking in the bench press by training just slightly less than your fatigue limit, which means leaving 1-2 reps left in the tank by the time you finish your set. As well, you’ll want to increase your stabilizer strength by practicing techniques that enhance full body tightness and implementing exercises that work your smaller muscle groups.

Final Thoughts

Shaking in the bench press is a sign of muscular fatigue.  You can get muscular fatigue for several reasons, ranging from training close to your fatigue limit, introducing a new training stimulus, and inefficient technique.  Once you’ve identified the underlying cause for why your muscles shake, you can start to address it with changes to your training program and technique.