An extremely common question you’ll often hear is, “Why Do I Feel Leg Press in My Knees?”
While many resistance machines are not typically viewed as effective as free-weights, the leg press has many fans.
The leg press machine, whether sitting up straight or performed at an incline angle, has huge benefits for lower body size and strength.
However, it can also cause certain problems, and this especially true when it comes to feeling it in your knees.
So, I’d like to discuss why you’re potentially feeling leg presses in your knees, and what you can do about it.
Why Do I Feel Leg Press in My Knees?
The main reason you feel leg presses in your knees is because you are fully locking out at the top of the movement. This causes your knees to hyperextend and places a huge amount of stress on the knee joints. You should also be wary of your knees turning inwards whenever you leg press, as this will also place stress on the joints. Additionally, if you use the leg press in place of a barbell exercise, such as squats, your stabilizing muscles may not be as strong. You should also ensure that your entire back stays firmly against the seat throughout.
1. You’re Hyperextending the Knee Joint By Locking Out
Leg presses are without doubt a great exercise, but they are notorious for causing lower back and knee problems.
However, this is generally more of a technique issue rather than the exercise itself.
When it comes to feeling leg presses in your knees this is usually because you are fully locking out at the top.
In effect, you are jamming your legs out completely straight and hyperextending the knee joint.
Unfortunately, this will place a huge amount of stress on the knee joint.
Plus, not only will you feel this in your knees immediately afterwards, it can also eventually lead to an injury.
You should always maintain a slight bend in the knees when performing leg presses.
In fact, this is better for muscle and strength development, as it applies constant tension to the working muscles.
As soon as you fully lock out on leg presses you’ll take the stress off the quads and place it onto the knee joints.
So, in reality you’re reducing the effectiveness of the movement, while increasing the likelihood of an injury.
2. You’re Allowing Your Knees to Point Inwards
Something else you should be wary of when leg pressing is what your knees are doing during the movement.
Leg presses are typically viewed as a great quad-builder, but they also happen to hit the glutes and hamstrings really well too.
In fact, you can target various muscles of the lower body more depending on where you place your feet on the pad.
If you place your feet lower or closer together on the pad you’ll target your quads more.
If you place your feet higher on the pad you’ll target your glutes and hamstrings more.
Plus, you also work your adductors and hamstrings to greater effect by having a wider stance.
However, irrespective of where you place your feet on the pad you’ll want your knees to remain straight in a direct line over your feet.
If you’re feeling leg presses in your knees there’s a good chance that your knees are pointing or falling inwards.
This is very similar to when your barbell squat with a weight that you potentially can’t handle.
The knees typically buckle inwards, which once again places a great deal of stress on the joints.
So, if you find that your knees are pointing inwards, you should reduce the weight and immediately fix your form.
3. Your Stabilizing Muscles Are Weak
I won’t get into the debate of Leg Press vs Squats.
In my mind they are two completely different exercises.
Plus, for a greater all-round physique you would be better off performing both exercises.
However, something that you should be aware of is the difference between using resistance machines and free weights.
You will typically find that when you use free-weights many of the stabilizing muscles are fully engaged and activated.
Unfortunately, in most cases the same cannot be said when using a resistance machine.
And the leg press is certainly no different.
When you compare the leg press to the barbell squat there is a vast amount of difference.
During barbell squats you will engage many of the important smaller muscles in the hips, knees, and ankles, as well as the core.
This will actually help to develop greater lower body strength and stability in the muscles.
With that being said, if you rarely train with free weights then these stabilizing muscles will never get trained.
So, in effect, you’ll find that the smaller supporting muscles surrounding the hips, knees, and ankles are much weaker.
This of course could lead to you feeling the stress on your joints more.
So, if you’re feeling leg presses in your knees, this could well be a sign that the stabilizing muscles are weak.
Leg Press Vs. Squat For Lower Body Gain
4. You Are “Butt-Winking” During Leg Presses
“Butt-Winking” is typically more common when you squat, but it can also happen during leg presses.
Basically, you are going into posterior pelvic tilt.
In other words, the front of the pelvis rises and the back of the pelvis drops.
This will usually mean that your lower back isn’t in contact with the seat of the leg press machine.
I’ve mentioned that leg pressing can also cause issues with the lower back.
And this generally occurs because your lower back isn’t in contact with the seat.
However, this yet again places additional stress on the knee joints too.
If any part of your back comes away from the seat during leg presses you will definitely place a great deal of pressure on the lower back.
This in turn can cause you to either hyperextend at the knees or your knees will collapse inwards.
In effect, your body is trying to compensate for the stress placed on the lower spine.
But, this use of poor technique is simply asking for an injury to happen.
Whether it’s your lower back or knees that give out first is neither here nor there.
5. Try Activating Your Glutes & Hamstrings Beforehand
One of the most common reasons for “butt-wink” or posterior pelvic tilt will be tight or weak hamstrings or glutes.
And unfortunately a tightness or weakness in these areas can actually affect many quad-based exercises.
Firstly, the quads and hamstrings are antagonistic muscle groups, or opposite muscles.
So, when one muscle group contracts the other extends, and vice versa.
Plus, many lifters and trainees, whether new or experienced, tend to be fairly quad-dominant.
Therefore, the ideal solution would be to increase the amount of hamstring work you do.
I will also say that it’s important to work the glutes just as much, if not more.
The glutes obviously also form part of the posterior chain, and they’re the largest muscles in the human body.
I find that engaging and activating my glutes and hamstrings prior to movements such as barbell squats and leg presses pays huge dividends.
So, I would recommend that you work on hamstring and glute mobility before you leg press.
You’ll find that this increases flexibility in the posterior chain, which will help you to perform leg presses pain-free.
Plus, this will also help with increases in size and strength in the lower body.
Best Hamstring Exercises With No Equipment
I hope you have a better understanding of why you feel leg presses in your knees.
Without doubt, the most common reason is because you’re locking out and hyperextending the knees.
However, you should also ensure that your knees don’t turn inwards and that your entire back remains tight against the seat throughout your set.
Furthermore, if you’re not training regularly with free weights your stabilizing muscles are likely to be weak.
So, you are simply applying more pressure to the joints whenever you leg press.
You should also engage and activate your glutes and hamstrings first, as this will help to increase your overall mobility.
Hi, I’m Partha, the founder of My Bodyweight Exercises. I’m someone who’s been passionate about exercise and nutrition for more years than I care to remember. I’ve studied, researched, and honed my skills for a number of decades now. So, I’ve created this website to hopefully share my knowledge with you. Whether your goal is to lose weight, burn fat, get fitter, or build muscle and strength, I’ve got you covered.