The leg press appears straightforward and highly effective in facilitating muscle building and heavy weight shifting.
However, one of the main complaints that people have is that their butt tends to lift whenever they perform leg press.
You realise that the seat and the pad are there for a reason, i.e. to ensure that your back and butt stay glued to them throughout the movement.
But, this doesn’t stop the curse of the rising butt.
So, allow me to explain why this happens and what you can do to fix it.
The main reason your butt lifts on leg press is because you’re lowering the sled too far. You should never complete the entire range of motion on leg press. If you lower the sled too far your thighs will typically be against your chest, thus forcing your butt to lift, and placing stress on your lower back. You should also never fully lockout on leg press, as this places stress on the knees.
You’re Lowering the Sled Too Far
You’re generally told that you should always take every exercise through its full range of motion.
This is especially true if you’re training for hypertrophy.
Okay, I’ll admit that there is a place for partial reps, negatives only, etc. but in the main you’ll always want to take a movement through its entire range of motion to reap the benefits.
With that being said, the leg press machine is definitely one exercise you shouldn’t be doing this with.
The leg press isn’t exactly what you’d call a normal human movement pattern, as it forces the body into an unnatural position.
Plus, even though your thoracic spine is glued to the pad throughout, your lumbar spine is somewhat exposed.
This is especially true if your butt lifts off the seat.
And the main reason this occurs is that you’re lowering the sled too far.
I would hazard a guess that this mainly happens in an attempt to take the movement through the full range of motion.
In effect, your thighs are literally touching your chest at the bottom of the movement.
You need to immediately stop doing this, due to your lumbar spine being left vulnerable whenever your butt lifts off the seat.
The same can be said for fully extending your legs when you press, as this can typically lock the knees out and place a lot of undue stress on them.
Obviously, you don’t want to make the mistake of performing extremely shallow reps where the sled only moves a couple of inches.
However, you do need to find that safe middle ground that won’t expose your lower back and knees.
You Have No Control of the Negative
This actually ties in quite well with what I’ve just spoken about.
However, if you have no control over the negative portion of the lift it’s likely that you’ll once more end up lowering the sled too far.
And of course this means that your butt’s going to lift off the seat.
When it comes to resistance training you’ll generally find that it’s the negative part of most lifts that is responsible for building muscle.
Basically, the negative is usually when the muscle fibres and tissues are damaged from exercise, before repairing themselves when you rest.
So, in effect, the more control you have over the negative part of the leg press, or any exercise for that matter, the better chance you have of building muscle.
Quite often I see people literally slamming the leg press down on the negative, but putting all their effort into pressing the sled away from them.
You’ll want to stop the sled just short at the bottom, which not means that you won’t be lowering the sled too far, but also that you’ll be keeping constant tension on the muscles.
This is ideal when it comes to building muscle.
You’re Trying to Leg Press Too Much Weight
Once again, I guess you could say that this ties in well with what I’ve already said.
However, the simple fact that the leg press machine will probably allow you to lift more weight than any other exercise in the gym often leads to ego lifting.
Basically, your pride’s cashing cheques that your body can’t handle.
Yes, I’ll agree that the leg press is a great exercise for hypertrophy, plus it allows you to pack on some serious weight, but this shouldn’t be at the expense of good form.
I think one of the main problems with the leg press machine is that people believe that all their muscles and joints are well protected, so they can lift as much weight as possible.
With that being said, I’ve already spoken of the potential stress placed on the lower back and knees.
And this can be made worse if you’re simply trying to press too much weight.
This will usually become noticeable when your butt lifts off the seat and you are unable to control the negative.
Basically, you’ve put everything you’ve got into pressing the plate away from you so that form goes out the window for the rest of the movement.
I will also say that you should be wary of your head and neck.
If you find that they are coming away from the pad this is usually a sign that you may be trying to leg press more weight than you should.
Your Feet Are Too High
Foot position plays a major role in where you’ll feel leg press and which muscles you’ll work.
I’m sure you’ve heard about having your feet wide, close together, high, low, turned slightly inwards, turned slightly outwards, etc.
Basically, with every different foot position a certain area of your legs will have to work harder.
One of the more popular ways to leg press is with your feet high on the pad.
The higher your feet are on the pad, the more you target the glutes and hamstrings.
And, let’s face facts, training over the last decade or so has become much more focused on the glutes.
Not only do we all want a fantastic-looking butt, we’ve also come to realise that training your glutes has a huge transfer to your overall physique and athletic performance.
In other words, if you want to look good naked and be in the prime of physical fitness, train your butt.
However, I frequently see people with their feet far too high on the leg press machine.
In fact, it’s not unheard-of to have your heels at the very top of the sled, while mid-foot and toes are not supported.
Yes, I’ll agree that pushing through your heels will activate your butt more, but this shouldn’t be done at the expense of your spinal health.
Make sure you keep your entire foot on the sled.
With that being said, when your feet are too high on the sled, you tend to up in an unnatural scrunched up position.
In fact, it’s very similar to the position you end up in when you lower the sled all the way down and have your thighs against your chest.
However, if you start your press from this position you’ll place a huge amount of stress on the lumbar spine.
And this is typically made worse by your butt lifting off the seat, as your feet are so high.
So, if you want to focus more on your glutes and hamstrings, by all means place your feet higher, but just be sensible about it.
Final Thoughts
So, as you can see, there are a variety of reasons why your butt lifts on leg press.
However, the common of these is definitely that you’re lowering the sled too far.
You shouldn’t lower the sled completely until your thighs are literally touching your chest.
This will usually force your butt to rise, as well as placing a huge amount of stress on the lower back.
You should also make sure that you control the negative, don’t use too much weight, or have your feet too high on the sled.
All of these scenarios may force your butt into the air, plus they’re not good for your spine or joint health either.
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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.