Here’s Why Your Abs Shake While Exercising Them

It is not uncommon for many individuals to experience shaking abs when they do core exercises like crunches, plank, etc. Why does this happen? Can you stop it? Is it bad for your abs, and how bad is it?

There are a few reasons why your abs shake when you exercise them. The primary reason is that motor units that fire and contract the abs get fatigued quickly because they are not used to being worked. Other reasons include the abs not having enough energy from either low glucose levels or the anaerobic energy system.

If you want to know why your abs shake uncontrollably when you exercise them, this article will give you all the info you will ever need to understand why they do and how to stop it. Additionally, it will cover other FAQs regarding abs that you should know about.

Abs (abdominals) overview

You might not know it but your abs are responsible for a lot. You dont only exercise and use them when you are training but rather almost all the time (or they should be getting used all the time).

When you stand, sit, walk, talk, sing, run, cycle, lift weights, and almost anything else that involves movement or stability of your body you should essentially be utilizing your core. Your core consists of your abdominals and your lower back muscles.

Why do my abs shake when I work out

You probably don’t realize it but your core is weaker than you think and along with low glucose levels and a limited supply of energy your body can provide to your abs, this will be the cause for shaking abs along with any other muscles that you exercise.

Your abs shake because they are weak and fatigued

We touched on how your core (abs) stabilizes your body, and when you proceed to train them, and they are weak, more likely than not, they will start to shake only a couple of reps into the exercise, or if you are doing timed exercises like the plank or superman, you’ll probably start to experience this around 20 seconds into the exercise.

When your abs are weak and you start to exercise them, your body (brain) does not really know how to recruit and call on your abdominal muscles and their fibers to stabilize and work those muscles.

Trying to build strength with very weak abs causes a lot of stress on them, and thus they will fatigue quickly. Fatigued muscles can’t keep up with the exercise and produce the required amount of energy that the body and those muscles need in order for them to function correctly during the workout.

Understanding Muscle fibers

Everything in your body, including your muscles, is made up of cells when considered at a microscopic level. Now, when you perform crunches or any form of abdominal exercise, the stronger your abdominals are, the more these cells will work together. When your abs are weak, they don’t work in conjunction with one another so well.

These muscle cells are part of a group that connects to the spinal cord through a neuron, and it controls the individual nerve and muscle cells. To make things a bit simpler, everything gets controlled by what is known as a motor unit.

When you start your abdominal exercises, your brain will tell those motor units to fire and contract, and for the most part, all of them do so perfectly fine.

As you start to progress through the exercise, more motor units become fatigued, and subsequently, they will not fire and contract, essentially making your abs weaker, and this is why they start to shake as well.

Shaking abs are utilizing the anaerobic energy system

Another factor to consider is that of aerobic and anaerobic exercise. Although when you are doing abdominal exercises such as crunches or leg raises, etc., or timed core exercises, you will not be using the aerobic system, but rather you will be using the anaerobic system to a degree.

It won’t be the same as a HIIT workout where you are working your heart rate at its maximum level, but rather, the body will try and obtain energy in the same way, especially if your muscles are weak. This means that your muscle will break down stored ATP from carbohydrates very fast and not use oxygen to process energy as with the aerobic energy system.

The anaerobic energy system is a system with a limited energy supply, typically 10 to 20 seconds. After that energy has been expended, your body more than likely can not carry on.

This is why interval training is based on time, heart rate, and fitness level. Hence, after you have done a couple of crunches or the plank for 20 seconds, your abs start to shake.

This is because they have run out of energy. Thus, your muscles (because they are so weak) are trying to get energy as fast as possible, and utilizing the anaerobic system depletes the energy fast.

Your abs shake because you have low glucose levels

You don’t even need to exercise for this condition to set in. When your body experiences a drop in its glucose level (percentage of sugar in the blood), it becomes weaker.

This is further compounded if your glucose levels are low and you start to exercise. Your muscles will try and produce energy from the already low glucose levels in the blood, and they just can’t do that. Thus your energy levels will drop, and your muscles that are further fatigued will start to shake.

This can happen with your abdominals or any other muscle group that you are exercising.

How to increase my glucose levels so my abs don’t shake?

This alignment is pretty easy to rectify. You just have to make sure that you eat before your workout so your body has enough energy that it can use during your exercises.

This means you should typically eat some combination of carbohydrates and protein, preferably an hour or two before you hit the gym. This will give your body time to break down the food into an energy source it can use during your workout.

This video below talks about shaking after a workout but the same principles and conditions apply during your workout.

Are shaking abs bad?

On the contrary, shaking abs is actually a good sign. When your muscles shake, you know that you have fatigued them to a point where they are unable to work anymore.

Remember that when exercising, the point is to break down the muscle fibers and cells (as many as you can) so that they can repair themselves in order for them to build more endurance, tone, and get bigger and stronger, essentially building lean muscle mass.

When your abs start to shake, you have subsequently broken down as many muscle fibers and cells as humanly possible. The only thing to do then is to repair them, and that is where rest and nutrition play the biggest role.

There are instances where you can over-train them, but typically when they start to shake, the muscle group (in our case, the abdominals) will be too tired to carry on, so you won’t really be able to over-train them.

Is it bad to overwork your abs?

Yes, it is bad to overwork your abs. Just like with any other muscle group, it is not recommended that you overwork your abs. Overworking a muscle group can lead to excessive fatigue where your body will be prone to injury (pulled or torn muscle) not only for that particular muscle group but for your entire body as well.

This means your body will struggle to recover, and you won’t be able to exercise other muscle groups correctly.

The other thing to note, as we stated, is that overworking your muscles (your abs) makes them more susceptible to injury. If you overwork a muscle group, they struggle to recover and will take longer to do so. When your body is weak, and it is being exercised, there is a high chance that you will pull or tear something.

Remember that this doesn’t have to be the muscle that has been overworked. For example, let’s say that you overworked your abs and you train your legs the next day.

Squats (the exercise) uses a large percentage of your core (abdominal muscles) to stabilize and control the weight. Due to the fact that your abs are now weak and tired, they won’t be able to control the amount of weight you are used to. You think everything is fine and still use the same weight.

Your abs, not being able to withstand the pressure, distribute the weight to other muscles (perhaps your lower back and your quads). Subsequently, you rupture your lower back or tear your quads during your squat because of your weak abdominals. This is very possible and has happened more times in the gym than you know.

Is it bad to do abs every day?

It is definitely not a good idea to train your abs every day, as we just discussed (later in this article, we will discuss how many times a week you should be training your abs).

Your abs need time to rest and recover just like any other muscle group, and this is even more important if you find that your abs are weak and they shake when you work them out.

If your abs do shake, then we recommend not training them every day, especially if you are exercising your abs in conjunction with other exercises and other body parts.

How do I get my abs to stop shaking?

During a workout, there is not much you can do. However, after supplementing your body with the correct fuel and rest the next time you are at the gym, they should shake less.

The other way to get them to shake less for your following workouts is to do many variations of abdominal exercises. Remember that your abs do not just comprise of the “6 pack” that most people think of, but rather there are many more muscles that are also considered part of your core.

Training these specific muscles with a variety of exercises will make your core stronger, and hence, you will not experience shaking abs. The abdominal muscles consist of the transversus abdominis, the rectus abdominis, the external oblique muscles, and the internal oblique muscles.

You will need to work these muscles with different abdominal exercises and not just the standard old crunches. At the end of this article, we give you the ultimate ab workout that you can incorporate into your exercise routine.

How many times a week should I exercise my abs?

Many individuals think you can train abs every day, but this is not optimal, and as we stated, not only your abs but your body and other muscle groups could be prone to injury if you do.

Your abs are just like any other muscle group and require approximately 48 hours for recovery. If you are going to the gym every day and exercising other muscle groups, many of those exercises will utilize your core for stability, which will work your abs even further.

Thus there is no need to train your abs every day, and no more than three times a week should be more than appropriate and beneficial for them to get stronger and grow.


We discovered that your abs shake when you exercise them because of several factors. Primarily if there is nothing wrong with your glucose levels, then the reason will be because they are weak.

Weak abs will not have the capability of recruiting all the motor units it needs in order for your muscles to function and work through the exercise correctly because they will get fatigued.

The anaerobic energy system also plays a part in exercise when you work your abs. Not to a severe degree as when you are doing a HIIT workout, but it utilizes and produces energy the same way. This means it is limited and only available for a short time (20 seconds).

After this, your muscles can’t get enough energy fast enough, they fatigue, and hence, they start to shake.

The last reason your abs would shake is if your glucose levels are low, and not only will your abs shake but also any other muscle group and even your whole body in some instances. To remedy this, you just need to make sure you eat (have energy) before your workout.

To fix weak shaking abs, the only thing to do is train them, train them with various exercises and let them rest and recover. Then the next time you are at the gym, you will find that they shake less.

Lastly, you should only be training abs approximately three times a week, especially when used in a split routine, and you are lifting heavy weights for your legs, back, and chest.

Source List

Why Shaking Abs During Crunches Are Actually a Good Sign

If Your Core Shakes Like a Leaf During Ab Work, Here’s Why — and How to Make It Better

Why Am I Shaking After My Workouts??

Can you Work your Abs Everyday? The Truth about Working Out Abs Everyday

Abdominal muscles

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