Why Do My Legs Shake When I Squat? (5 Reasons And How To Fix)

legs shaking in the squat happens due to muscle fatigue, which usually occurs with high rep training

Leg shaking in the squat is a concern for both novice and experienced lifters. If your legs shake from time-to-time, it’s not a huge deal.  However, if you find it happening regularly, then a more persistent issue could indicate factors limiting your squat strength and technique.

So, why do your legs shake when you squat?  Legs shaking in the squat usually happens due to muscle fatigue, which occurs with high rep training. Your legs can also shake when introducing new movements, lifting with poor technique, or due to muscular imbalances. Factors that increase the chance of shaking are: being under recovered, underfed, or dehydrated.

At the end of this article, you will understand why your legs shake when you squat and solutions to fix it.

I will cover:

  • What it means when your legs shake in the squat
  • 5 reasons why your legs shake 
  • Solutions to stop your legs shaking

What Does It Mean When Your Legs Shake When You Squat?

muscular fatigue happens when you are training hard on squat

Provided you are a healthy individual with no neurological conditions (Parkinson’s disease, stroke, etc.), then legs shaking in the squat is caused by muscular fatigue.

Muscular fatigue happens when you are training hard via either maximal loading (such as a 1 rep max), when you are pushing close to failure (maximal rep sets), or when overall workload is too high (you are doing too many reps, sets or too much load in a single session). 

The Shaking Should Not Be Every Rep

Shaking occurs due to muscular fatigue, so should only be present in a fatigued state.

Your legs should not be shaking during the first few reps of a set of 8-10, but towards the end of the set the last couple of reps you may notice the shaking as the set gets harder and your muscles fatigue.

If your legs are shaking during the first rep of a lower rep set (1-5), then perhaps the load is too heavy (or simply a maximal attempt) or you have not had enough rest between sets.

As you train more, your body will be able to handle higher loads, volumes (total reps and sets) and even frequency (more sessions per week) before the onset of shaking. This is often referred to as “work capacity”, by building this, your muscles can train more before fatiguing. 

If Shaking Is A Sign Of Fatigue, Is It A Good Thing?

While we want to be training hard enough to stimulate the muscle and cause an element of fatigue, there is a scale of how much fatigue we want present in a training session, week and even longer.

If you are commonly training to the point of muscular shaking, then you are likely pushing beyond the fatigue levels you want to see in a training program and put yourself at risk of overtraining and even injury.

Shaking occasionally in your heaviest or hardest training sessions towards the end of a training block is not an issue.

Frequent leg shaking in the squat could be indicative of other issues though, which is why you need to look at your technique, recovery and overall programming factors to understand if there are any other reasons why you may be excessively fatiguing.

Are you having the same issue in the bench press? Read our article Why Do Your Arms Shake In The Bench Press?

Want to improve your squat technique?

5 Reasons Why Your Legs Shake While Squatting

the 5 reasons why your legs shake during squats

The 5 reasons why your legs shake during squats are:

  • Forming New Neurological Connections
  • Weak Muscle Groups
  • Your Stance Is Too Wide Or Too Narrow
  • You Are Under Recovered
  • You Are Under Fed Or Dehydrated

1. Forming New Neurological Connections

If you are brand new to squatting, or coming back to it after a prolonged break, then this is the process of your brain and muscles forming new connections which can result in a lower fatigue threshold. This in turn means you may experience shaking at lower intensities or difficulties than usual.

As you are training new movements and muscle groups, these muscles are not used to the stimulus yet and therefore fatigue occurs much faster.

The Solution:

The only solution here is to raise your fatigue threshold by improving your work capacity. This can be done by continuing to stimulate the muscles by squatting.

Train with loads that do not cause you to shake and look to build up overall volume (sets and reps) at this same load. Aim to stop 2-3 reps short of failure each set.

Over the course of several weeks, you can aim to increase load, but the primary measure of progress here will be increasing the load at which your legs begin shaking.

If you are newer to squatting, read our article 11 Squat Progressions From Beginner To Advanced to learn more about the best squat variations for you as you progress.

2. Weak Muscles Groups

Weak, or comparatively weak, muscle groups can cause your legs to shake during the squat.

By comparatively weak, I mean from side to side or between muscle groups. The squat recruits several muscle groups in the lower body and an imbalance in strength between these can lead to instability, fatigue and shaking.

For example, an imbalance between weaker hip extensors (glutes, adductors and hamstrings) and stronger knee extensors (quadriceps) can lead to the hip extensors fatiguing earlier than the quadriceps causing instability and shaking.

These imbalances lead to fatigue occurring a lot quicker in the squat and therefore the legs will shake more often.

The Solution:

The solution here is to address your muscular weaknesses with specific training outside of the squat and to target the muscles that are worked less within the squat.

Unilateral work will be key for those with imbalances side to side but are also a great way to train specific muscle weaknesses in the lower body.

My three favourites here are:

  • Split Squats – These are great for targeting the quadriceps and glutes and addressing strength imbalances while also improving your ability to stabilise each leg under load. Perform 3-4 sets of 8-12 reps.
  • Copenhagen Planks – The adductors are a primary hip extensor at the bottom of the squat but are also responsible for stability throughout the movement. The Copenhagen plank is great for developing the ability to stabilise your lower body and to strengthen the adductors. I recommend performing 3-4 holds per side of 15-25 seconds.
  • Single Leg Hip Thrusts – These will target the glutes and help improve your unilateral stability on each side. Perform 3-4 sets of 8-12 reps.

For more exercises to benefit your squat, read our article 20 Exercises To Improve Squat Strength.

3. Your Stance Is Too Wide Or Too Narrow

a stance too wide or too narrow can cause instability in the squat

A stance too wide or too narrow can cause instability in the squat, which leads to the muscles having to work harder in order to complete the movement or is putting the muscles in positions that make it harder for them to produce force.

By causing the muscles to work harder to produce the base amount of force to complete the movement, they will fatigue more and therefore you are more likely to experience leg shaking during the squat.

You will know if your stance is too wide or too narrow if there is excessive side to side movement of your legs through the descent and ascent. Knees excessively coming in will suggest your stance may be too wide, whereas excessively driving your knees out may be due to having a stance that is too narrow.

The Solution:

Fortunately, there is a quick solution for this, adjust your stance.

Most lifters will benefit from a stance that is just outside shoulder width apart. This allows you the room to sit into the bottom of a squat without having to drive your knees excessively outwards, while also being narrow enough that your knees are not tracking inwards.

A good squat stance is one that allows your knees to track over your feet and to feel the load spread evenly throughout your lower body.

Looking to avoid more technique mistakes in the squat? Read our article Top 17 Squat Mistakes (How To Avoid And Correct)

4. You Are Under Recovered

Shaking in the squat is caused by fatigued muscles, and under recovered muscles are more prone to fatiguing quickly. This applies both within a session and between sessions.

Within a session, if you go to do your next set and your legs are shaking on the first couple of reps, or even on the walkout, this is an indicator that you are under recovered and have not taken enough rest between sets.

Between sessions, if your legs start shaking on your first set or even your warmups, this indicates you have not taken enough time between sessions to allow your muscle to recover.

The Solution:

The solution here is to increase your rest periods.

Within a session, if you are only taking rests periods of 60-90s between sets, try increasing this to 120-180s. Allow yourself the time to recover between sets so that you can maximise the performance of your next one.

Between sessions, if you are only taking 1-2 days rest between squat sessions, try increasing this to 2-4 days. Allowing yourself to recover between sessions is a key element of good training and enables you to perform better and increase strength and size quicker.

5. You Are Under Fed Or Dehydrated

The final reason you may shake during the squat is that you are underfed or dehydrated.

A shortage of food and/or water prior to a session can cause increased and earlier muscle fatigue and hinder recovery from the previous sessions.

Prior to hard exercise, the body needs adequate hydration and fuel (in the form of carbohydrates) to train properly.

The Solution:

Ensure you have a high carbohydrate meal 1-3 hours prior to training and aim to drink 500ml-1 litre in this time frame too.

Take a bottle of water with you to training as well, as you can quickly become dehydrated in the gym too.

Frequently Asked Questions

How Do I Stop Shaking During The Squat?

To stop shaking in the squat ensure you are adequately fed, hydrated and recovered for your session. If you are still experiencing shaking, then you should look to address weak muscle groups or imbalances and technique. As a beginner, you may experience shaking as your muscles adapt to squatting.

Is Shaking In The Squat Bad?

While infrequently shaking in the squat is not bad, a more persistent issue could indicate factors limiting your squat strength and technique. This is often caused by under recovering or being underfed and dehydrated. Beyond this, it could also be a technical or muscular limitation.

Final Thoughts

Shaking in the squat is a sign of muscle fatigue. This occurs when training close to failure, introducing new movements, inefficient techniques or due to recovery issues. Identifying the cause of your shaking is important in addressing and reducing its occurrence.

About The Author

Jacob Wymer

Jacob Wymer is a powerlifting coach and PhD Candidate in Biomechanics and Strength and Conditioning, researching the application of barbell velocity measurements to powerlifting. He is involved in powerlifting across the board, from athlete to meet director. Jacob runs his coaching services at EST Barbell. You can also connect with him on Instagram.