I’ve spoken to many people over the years who complain of knee pain from Bulgarian split squats.
However, a quick form check and shoring up posterior chain weaknesses will allow you to perform the movement pain-free.
Bulgarians split squats will hurt your knees due to poor technique or certain muscle weaknesses. Allowing your front knee to travel past your toes will cause knee pain if you don’t have the required flexibility and joint mobility. Loading your back leg with too much of your body weight (90% of your body weight should be loaded on the front leg) will once again cause issues with your knees. Weak glutes, hamstrings, and lower back can be especially damaging for your knees.
Are You Feeling Pain in Your Front Knee?
The main reason that you’re feeling your front knee during Bulgarian split squats is due to your knee going past your toes.
Now, you’ll typically hear that your “knees going past your toes” for any squat variation is an absolute no-no.
In fact, you should avoid this at all costs.
This is NOT true.
Realistically, a full range of motion squat means that your knees should travel past your toes.
However, this requires a great deal of joint flexibility.
And unfortunately many people don’t possess the required flexibility, which is why squats of any type cause them knee pain when their knees go beyond their toes.
I would also say that if you have a history of knee issues it’s likely that going past the toes will also cause you pain.
That being said, a Bulgarian split squat, even when performed with a full range of motion, shouldn’t see your front knee go past your toes.
Now, the main reason for this is that Bulgarian split squats are an up-and-down movement.
So realistically, both your front and back legs should form a 90-degree angle when at full range.
This will mean that your front shin should remain vertical.
I think the confusion lies in the way that you should perform lunges, which are a forward and backward movement.
But, it’s important to remember that Bulgarian split squats are in fact a squat and not a lunge.
You also need to ensure that your front knee remains directly over your ankle throughout the movement.
There is a tendency, due to muscle weaknesses (which I’m about to cover below) for the front knee to collapse inwards during Bulgarian split squat.
So, also be wary of your knee and ankle position.
Potential Weaknesses That Will Increase Front Knee Pain
Something else to consider if your knees hurt is that you are quad-dominant.
And to be honest, many lifters are extremely quad dominant simply because of how they train.
If this is the case you’re likely to have weak or tight hamstrings and glutes.
Plus, your glutes probably aren’t firing and being activated when you squat.
And it’s also possible that you have a weak lower back.
All these factors will automatically put even more strain on your front quad, which in turn can inflame the knee.
Furthermore, if your knee does go beyond your toes you’ll probably find that your front heel comes off the floor.
This limits glute involvement during Bulgarian split squats, which once more places additional stress on the front quad and knee.
The solution would be to make these muscles stronger and more flexible.
The most important muscle would be the glutes, as they are the largest muscle group in the body.
So, it’s important to work on activating and strengthening the glutes.
And then ensure you work on your hamstrings by incorporating some of the exercises in the video below.
What you’ll eventually find is that by working on your glutes and hamstrings you’ll also strengthen your lower back.
Plus, this will help you to avoid front knee pain from Bulgarian split squats.
Is Your Back Knee Hurting During Bulgarian Split Squats?
Okay, front knee sorted, so let’s move onto the back knee.
Now, there are a number of reasons why you’ll feel Bulgarian split squats in your back knee.
And once again, these all come down to incorrect form or potential muscle weaknesses.
Firstly, it’s important to understand the weight distribution between the two legs.
Realistically, during Bulgarian split squats 90% of your body weight should be loaded onto the front leg.
Essentially, this is as close to a single-leg exercise as you’ll get with lunge and split squat variations.
Therefore, this means that only 10% of your body weight should be loaded on the back leg.
I guess another way to look at it is that your back leg is there in a supporting role, while your front leg is doing the majority of the work.
So, if you happen to overload your back leg it is likely to cause you knee pain.
Too Narrow a Stance
The most obvious reason for this is that your stance is too narrow.
Admittedly, this is quite unusual, as most people tend to overstretch during Bulgarian split squats, which is typically what causes lower back pain.
However, with a shallow stance your back leg is loaded more, which immediately places more stress on the quad and the knee.
Furthermore, this may also see your front knee travel past your toes, which means you might even find that both of your knees hurt.
Obviously, there isn’t an exact distance you should stand away from the elevated surface behind you, as this will differ based on height and limb length.
So, find your sweet spot,which allows you to comfortably go up-and-down without overloading the back leg.
Are You Banging Your Back Knee?
Next, and far more obvious, is banging your back knee into the floor.
With a full range of motion Bulgarian split squat your back knee should actually come into contact with the floor.
However, if you lack flexibility you’ll typically find that your knee stays a few inches off the ground.
This is absolutely fine, and the more you perform the movement the more flexible you’ll become.
But, under no circumstances should you forcefully bang your knee into the ground.
Are You Pushing Off Your Back Foot?
I’ve mentioned that you should only be supporting approximately 10% of your body weight on your back leg and it is there simply to support you and help you balance.
However, some trainees will often push off the back foot, which of course means that you’re loading your back leg with more weight.
In truth, this also comes down to the position of your back foot.
Realistically, the top of your back foot should be resting on the raised surface behind you.
But, this requires a good amount of ankle flexibility.
For those lacking in adequate ankle flexibility they typically have their toes on the raised area.
This automatically leads to you pushing off the toes of your back foot and will largely explain why many people get foot cramps while performing Bulgarian split squats.
Plus, it activates the back quad to a greater extent, which is why you’re feeling the movement in your back knee.
Muscle and Joint Weaknesses
Once more, your need to put additional weight on your back leg comes down to weaknesses in the glutes and hamstrings.
Plus, it also shows potential weaknesses in the joints, be it your hips, knees, or ankles.
So, you’ll obviously need to work on your posterior chain to strengthen these muscles.
Additionally, ensure you use the “triple flexion” technique to improve mobility in the hips, knees, and ankles.
Finally, if you’re still struggling with Bulgarian split squats then perform standard split squats with both feet on the floor.
And if you’re back knee pain doesn’t go away then you can legitimately load the back leg by elevating your front foot.
Key Learning Points
- Pain in your front knee or your back knee during Bulgarian split squats is usually down to poor technique or muscle weaknesses.
- If your front knee hurts this is usually because your knee is going past your toes and you lack the joint mobility for this to be comfortable.
- Glute and hamstring weakness can cause you to be quad-dominant, which is why you’ll feel your front knee.
- If your front heel comes off the floor you will limit glute involvement, which places additional stress on the quad and knee.
- 90% of your body weight should be loaded on the front leg during Bulgarian split squats. The back leg is simply there for support and to help you balance.
- If your stance is too narrow you’ll apply more stress to the back quad and knee.
- Don’t bang your back knee into the ground.
- Try split squats with both feet on the floor if your back knee continues to hurt.
- Make split squats even easier on the back knee by elevating your front foot.
Hi, I’m Partha, owner and founder of My Bodyweight Exercises. I am a Level 3 Personal Trainer and Certified Strength & Conditioning Specialist through the Register of Exercise Professionals, United Kingdom. I have been a regular gym-goer since 2000 and coaching clients since 2012. My aim is to help you achieve your body composition goals.