Why Your Knees Cave In During Squats: Causes, Risks and How to Fix It

You walk up to the squat rack, position the bar across your shoulders, set your feet, and begin lowering yourself into a squat.

Everything feels fine until you reach the bottom.

As you push upwards, your knees suddenly move towards each other instead of staying aligned with your feet.

You might have noticed this in the gym, seen it in a training video, or had someone tell you to push your knees out while squatting.

This movement is commonly called knee valgus or dynamic knee valgus. It describes an inward movement of the knees during activities such as squatting, jumping, and landing.

But why does it happen?

Is it caused by weak glutes? Are your feet positioned incorrectly? Are you using too much weight? And should you stop squatting altogether?

The answer depends on your individual movement pattern, strength, mobility, technique, and training experience.

In this guide, we will explain why your knees may move inward during squats, how to assess your technique, and what you can do to develop better control.

What Does It Mean When Your Knees Cave In During Squats?

Knees caving in refers to the inward movement of one or both knees during a squat.

In a controlled squat, your knees should generally move in a direction that is compatible with your foot position. They do not have to remain perfectly straight or follow one exact line for every person.

Some inward movement can occur naturally, depending on your anatomy and movement pattern.

However, excessive or uncontrolled inward movement, particularly when it happens repeatedly under load, may indicate that your current squat technique or strength is not matching the demands of the exercise.

For example:

• Your knees move inward as you lower yourself.

• Your knees collapse towards each other as you stand up.

• One knee moves inward more than the other.

• Your feet roll excessively towards the inside.

• You struggle to maintain knee control with heavier weights.

The goal is not to force your knees into an exaggerated outward position.

It is to develop a stable, controlled squat that suits your body and allows you to move comfortably.

7 Reasons Your Knees Cave In During Squats

1. Your Glutes May Not Be Controlling the Movement Effectively

Your gluteal muscles play an important role in controlling hip movement during squats.

In particular, the gluteus medius and other hip muscles help control the position of your pelvis and thigh.

If your hip muscles are not producing or controlling enough force for the movement, your thighs may move inward more than you can comfortably control.

This can become more noticeable when you use heavier weights or perform multiple repetitions.

However, weak glutes are not the only explanation for knee valgus. Anatomy, coordination, ankle mobility, exercise technique, and fatigue can also influence knee movement.

How to improve it:

Include exercises that develop hip strength and control.

Useful options include:

• Side-lying hip abductions.

• Banded lateral walks.

• Clamshells.

• Glute bridges.

• Controlled single-leg exercises.

Start with a manageable resistance and focus on controlled repetitions.

The objective is to improve how your hips work during movement, not simply to make your glutes tired before squatting.

2. You Are Squatting With Too Much Weight

One of the most common reasons your squat technique changes is that the weight is too challenging.

You may be able to perform the first few repetitions with good control, but as the set becomes harder, your movement pattern starts to change.

Your knees may move inward, your hips may shift, or your torso may lean more than usual.

This does not necessarily mean you lack strength. It may simply mean that the weight exceeds the level you can currently control with consistent technique.

For example, imagine you can perform eight controlled squats with 40 kg.

When you increase the weight to 60 kg, your final repetitions become unstable and your knees repeatedly collapse inward.

The heavier load may be beyond your current technical capacity.

How to improve it:

• Reduce the weight temporarily.

• Focus on controlled repetitions.

• Avoid rushing through difficult repetitions.

• Increase resistance gradually.

• Stop the set when you can no longer maintain appropriate control.

Your squat should become stronger without sacrificing the movement quality you are trying to develop.

3. Your Ankle Mobility May Be Limited

Your ankles need to move during a squat, particularly when your knees travel forward as you lower your body.

This movement is known as ankle dorsiflexion.

If your ankle movement is restricted, you may compensate by changing your foot position, shifting your weight, or adjusting the movement at your hips and knees.

In some people, these compensations may contribute to poor knee control.

However, limited ankle mobility does not automatically cause knees to cave inward. The relationship between ankle movement and knee position varies between individuals.

How to improve it:

Try these mobility exercises:

Knee-to-wall ankle mobilisation

1. Stand facing a wall.

2. Place one foot a short distance away.

3. Keep your heel on the floor.

4. Move your knee towards the wall over your toes.

5. Return to the starting position.

6. Repeat with controlled movement.

Calf stretching

1. Stand facing a wall.

2. Place one foot behind you.

3. Keep the back heel on the floor.

4. Gently lean forward.

5. Hold a comfortable stretch.

6. Repeat on the other side.

These exercises may help improve ankle movement when restricted mobility is contributing to your squat limitations.

4. Your Feet Are Not Properly Positioned

Your foot position influences how your hips, knees, and ankles work together during a squat.

Some people naturally squat comfortably with their feet shoulder-width apart. Others need a slightly wider or narrower stance.

Your hip structure, limb proportions, ankle movement, and individual anatomy all influence which stance feels natural.

If your stance is unsuitable, you may struggle to maintain comfortable knee alignment.

Another common issue is allowing your feet to collapse excessively towards the inside during the movement.

How to improve it:

Experiment with small adjustments to your stance.

Try:

• Placing your feet around shoulder-width apart.

• Turning your toes slightly outward if comfortable.

• Keeping pressure distributed across your feet.

• Maintaining contact through your heel, the base of your big toe, and the base of your little toe.

This three-point foot contact is sometimes called the tripod foot.

Do not force your feet into a perfectly straight position if your natural movement requires a slight outward angle.

The best stance is one that allows you to squat comfortably with control.

5. You Have Difficulty Controlling Your Knees During the Lowering Phase

Squatting is not simply about lowering your body and standing back up.

You need to control the movement throughout the entire repetition.

Some gym members allow their knees to move inward as they lower themselves, particularly when they are rushing or trying to reach a particular depth.

Others maintain good control during the descent but lose it when standing up.

This can happen because different parts of the squat place different demands on your muscles and coordination.

How to improve it:

Practise slow bodyweight squats.

1. Stand in your comfortable squat stance.

2. Brace your abdomen gently.

3. Begin lowering yourself slowly.

4. Keep your knees moving in a comfortable direction over your feet.

5. Pause briefly at a depth you can control.

6. Stand up without allowing your knees to collapse inward.

Try three sets of eight controlled repetitions.

The aim is to understand the movement before adding additional resistance.

6. Your Muscles Are Getting Fatigued

Your squat technique may look excellent during the first set but change towards the end of a demanding workout.

As fatigue develops, maintaining the same level of muscular control can become more difficult.

You might notice:

• Your knees moving inward during the final repetitions.

• Your hips shifting towards one side.

• Your torso leaning forward more than usual.

• Your repetitions becoming faster and less controlled.

• Difficulty maintaining your normal squat depth.

Fatigue can affect coordination as well as force production.

How to improve it:

Adjust your training volume and rest periods.

Give yourself enough time between challenging sets, particularly when performing heavy squats.

If your technique starts deteriorating, reduce the weight or stop the set.

You do not need to complete every planned repetition when you can no longer perform the movement with appropriate control.

7. Your Body Structure Influences Your Squat Position

Not everyone is built to squat in exactly the same way.

Differences in hip anatomy, femur length, torso length, ankle structure, and individual mobility can influence your natural squat position.

For example, someone with longer femurs may need a different torso angle or stance compared with someone with shorter femurs.

Similarly, two people may need different foot angles to achieve a comfortable squat depth.

This is why copying another person's exact squat position does not always work.

How to improve it:

Experiment with your stance, depth, and squat variation.

You might find that a slightly wider stance, a different toe angle, or a heel-elevated squat allows you to move more comfortably.

The objective is to find a position that suits your anatomy while maintaining control and avoiding unnecessary discomfort.

If you experience pain or persistent movement limitations, a qualified physiotherapist or other appropriate healthcare professional can assess your individual movement pattern.

How to Fix Knees Caving In During Squats

If your knees repeatedly move inward during squats, the solution is usually to address the movement pattern rather than focus on one muscle group alone.

Here is a practical approach.

Step 1: Reduce Your Squat Weight

Start with bodyweight squats or a light load.

Your first priority should be learning to control the movement.

Do not increase the resistance until you can perform your chosen squat variation comfortably and consistently.

Step 2: Find Your Natural Foot Position

Experiment with a few comfortable stances.

Try:

• Feet approximately shoulder-width apart.

• A slightly wider stance.

• A slightly narrower stance.

• A small outward toe angle.

Choose the position that allows you to maintain comfortable balance and knee control.

Step 3: Practise Controlled Squats

Perform each repetition slowly enough to understand what your knees and feet are doing.

Avoid bouncing into the bottom position or rushing through the hardest part of the movement.

A useful starting point is:

• Three sets.

• Eight to ten repetitions.

• Bodyweight or light resistance.

• Controlled lowering and standing phases.

Adjust the number of sets and repetitions to your current ability.

Step 4: Strengthen Your Hips

Add hip-strengthening exercises to your programme.

Examples include banded lateral walks, side-lying hip abductions, clamshells, and glute bridges.

These exercises can help develop strength and control around your hips.

Step 5: Improve Ankle Movement if Needed

If your ankles have limited mobility, include suitable ankle mobility exercises.

Do not assume that everyone needs the same mobility routine.

Focus on restrictions that actually affect your movement.

Step 6: Record Your Squat Technique

Recording your squat from the front and side can help you notice movement patterns that are difficult to identify while exercising.

Look for:

• Whether one knee moves inward more than the other.

• Whether your feet remain stable.

• Whether your hips shift towards one side.

• Whether your technique changes as you become tired.

• Whether your squat depth affects your control.

A video can provide useful feedback, but it cannot replace an individual assessment when pain or injury is involved.

5 Exercises That Can Help Improve Knee Control

The following exercises can be useful additions to a training routine. They are not a guaranteed treatment for knee valgus, and the best selection depends on the reason your knees move inward.

<caption>Perform each movement with controlled technique and a resistance level appropriate for your ability.</caption>

1. Banded Lateral Walks

Main focus: Hip strength and control

• Place a resistance band around your thighs or lower legs.

• Bend your knees slightly.

• Maintain a comfortable athletic stance.

• Take small controlled steps sideways.

• Avoid allowing your knees to collapse inward.

Start with two or three sets of 10–12 steps in each direction.

2. Side-Lying Hip Abductions

Main focus: Hip abductor strength

• Lie on your side.

• Keep your lower leg comfortably bent.

• Extend your upper leg.

• Slowly raise it without rotating your pelvis.

• Lower it with control.

Try two or three sets of 10–15 repetitions per side.

3. Glute Bridges

Main focus: Hip extension strength

• Lie on your back.

• Bend your knees and place your feet on the floor.

• Tighten your abdominal muscles gently.

• Lift your hips.

• Pause briefly.

• Lower your body slowly.

Start with two or three sets of 10–15 repetitions.

4. Supported Split Squats

Main focus: Single-leg strength and control

• Stand in a split stance.

• Hold a stable support if necessary.

• Lower your body slowly.

• Keep your front foot stable.

• Maintain comfortable knee alignment.

• Push through your front foot to return to standing.

Try two or three sets of eight repetitions per side.

5. Box Squats

Main focus: Squat control and positioning

• Stand in front of a suitable bench or box.

• Position your feet comfortably.

• Lower yourself towards the box.

• Touch it gently without dropping your weight.

• Stand up with control.

Start with two or three sets of eight to ten repetitions.

Use a box height that allows you to maintain comfortable movement.

Should You Stop Squatting If Your Knees Cave In?

Not necessarily.

Inward knee movement does not automatically mean that you have injured your knees or that squats are dangerous for you.

The important factors include the amount of movement, whether it is controlled, the load being used, and whether you experience pain or other symptoms.

If your knees move inward slightly without discomfort, you may simply need to improve your technique and strength over time.

However, if you experience knee pain, swelling, instability, locking, or repeated giving way, stop the painful exercise and seek an appropriate assessment.

Do not force your knees outward aggressively or continue adding weight in the hope that the movement will correct itself.

A qualified physiotherapist can assess your strength, mobility, movement pattern, and symptoms to identify an appropriate approach.

Are Knee Sleeves or Resistance Bands the Solution?

Gym accessories can sometimes help with training feedback or comfort, but they are not a substitute for understanding why your knees move inward.

Resistance Bands

A light resistance band placed around the thighs may provide feedback during certain exercises.

Some people find it useful for practising hip control.

However, the band should not encourage you to push your knees excessively outward. Your aim is controlled movement, not creating the largest possible gap between your knees.

Knee Sleeves

Knee sleeves may provide warmth, compression, and a feeling of support during training.

However, they do not automatically correct knee valgus or fix underlying strength and movement limitations.

If your knee position is changing under heavy loads, reducing the weight and improving your technique is generally more useful than relying on accessories.

A Simple Weekly Routine to Improve Your Squat Technique

You can include the following exercises alongside your normal training programme.

Exercise	Sets	Repetitions
Banded lateral walks	2	10–12 steps each direction
Glute bridges	3	12
Side-lying hip abductions	2	12 each side
Supported split squats	2	8 each side
Controlled bodyweight squats	3	10

Perform this routine two or three times per week, depending on your overall training schedule and recovery.

These are suggested starting volumes, not mandatory targets. Reduce the workload if you experience pain or excessive fatigue.

As your control improves, you can gradually return to your normal squat variations and increase resistance appropriately.

For more guidance on planning your training frequency, read How Often Should You Go to the Gym?.

Common Squat Mistakes That Can Make Knee Control More Difficult

Even experienced gym members can develop habits that affect their squat technique.

Watch out for these mistakes:

Using weights that are too heavy: If you cannot control the movement, reduce the resistance.

Forcing your knees excessively outward: Your knees should move comfortably with your feet, not be pushed into an exaggerated position.

Allowing your feet to collapse: Maintain a stable foot position throughout the repetition.

Rushing through repetitions: Controlled movement makes it easier to identify and correct technique problems.

Copying someone else's stance: Your anatomy may require a different foot position or squat depth.

Ignoring fatigue: If your technique deteriorates towards the end of a set, stop or reduce the workload.

Ignoring pain: Knee pain is not something you should simply push through to complete your workout.

Frequently Asked Questions

1. Why do my knees cave in when I squat?

Possible reasons include reduced hip strength or control, limited ankle mobility, unsuitable stance, excessive training loads, fatigue, and individual anatomical differences. Several factors may contribute at the same time.

2. Is it bad if my knees go inward during squats?

Some inward movement does not automatically mean injury. However, repeated uncontrolled movement, particularly when combined with pain or instability, deserves attention. Improving movement control and adjusting your training load may help.

3. Do weak glutes cause knee valgus?

Reduced hip strength or control can contribute to inward knee movement, but it is not the only cause. Ankle mobility, coordination, anatomy, fatigue, and technique can also influence knee position.

4. Should I push my knees outward when squatting?

Think about keeping your knees moving in a comfortable direction that matches your foot position. Avoid forcing them aggressively outward. Your goal is stable, controlled movement rather than an exaggerated knee position.

5. Can weak ankles cause knees to cave in?

Limited ankle mobility or poor control of foot and ankle movement may contribute to changes in squat mechanics. However, not everyone with inward knee movement has an ankle mobility problem.

6. Are squats safe if I have knee valgus?

That depends on your movement pattern, symptoms, training load, and individual circumstances. Many people can perform suitable squat variations safely, but persistent pain, instability, or swelling should be assessed by a qualified professional.

7. How long does it take to fix knee valgus?

There is no guaranteed timeline. Improvements depend on the underlying cause, exercise consistency, training experience, and individual response. Focus on gradual progress rather than expecting a correction after a few sessions.

8. Do resistance bands fix knees caving in?

Resistance bands can provide feedback and help you practise certain hip-control exercises. However, they do not automatically correct the underlying cause. Use them as a training tool rather than a complete solution.

9. Why does only one knee cave inward?

Differences in strength, mobility, coordination, anatomy, or previous injury may contribute to one-sided movement. If the difference is persistent or accompanied by pain or instability, consider an individual assessment.

10. Should beginners use a squat machine instead of free weights?

Machines can provide additional support and make it easier for some beginners to learn resistance training. However, they do not automatically solve knee-control problems. Choose exercises that suit your current ability and allow comfortable, controlled movement.

Final Thoughts

If your knees cave inward during squats, do not immediately assume that you have weak glutes or that your knees are damaged.

There can be several contributing factors, including strength, mobility, coordination, fatigue, training load, and natural differences in body structure.

Start by reducing the weight, finding a comfortable stance, and practising controlled repetitions. Add appropriate hip-strengthening exercises and work on ankle mobility if it is genuinely restricted.

Most importantly, do not sacrifice movement quality to lift heavier weights.

A strong squat is not simply about how much weight you can put on the bar. It is about developing strength, control, and confidence throughout the movement.

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