The REAL Truth About Single Leg Exercises

Recently, a lot of well-respected strength coaches started declaring that single leg (unilateral) lower body exercises are superior to double leg (bilateral) lower body exercises.

In other words, the claim is that leg exercises involving one leg at a time (i.e. split squats) are superior to leg exercises that require you to train both legs simultaneously (i.e. barbell squats).

Is this assertion true? Well, before we start to blindly “drink the Kool-Aid”, let’s take a closer look.

We will start by examining the “big three” reasons why the single leg proponents wouldn’t dare step into a squat rack (the forth reason, of course, is the fear of embarrassment from unveiling their shameful lack of strength!).

Then I will follow each of their claims with my personal opinion, which is based on 20 years of “in-the-trenches” training and coaching:

Claimed Benefit #1- Unilateral leg training makes you more athletic. When you are playing your sport, you are rarely on both feet at the same time. Instead, you are more commonly on one foot at a time. Therefore, it is more sports specific to train on one leg. 

Tom: Hey coach, I'm ready to play! I've only been making one bad movie per year in order to have time to master the perfect lunge.

The Truth- The only activity that is “sports specific” is playing your specific sport. Period! I can assure you that no amount of lunges will turn the waterboy into the team captain. In the weight room, your only goals are to get stronger, more powerful, structurally balanced, and in some cases, bigger.

Claimed Benefit #2- Unilateral leg training is safer than bilateral training.

The Truth- I agree that unilateral leg training can be safer in some ways. Typically, single leg exercises cause less spinal compression.

This is because less loading is utilized with unilateral movements; thus, less compression on the spine is created when performing these exercises.

Also, when your legs are split, a more upright torso can be maintained, therefore decreasing stress in the lower back.

There is a flipside to this “safety” issue, however. Although the spine may be exposed to a reduced stress, the knees and hip flexors can suffer far more.

I’ve witnessed torn hip flexors from doing lunge/split squat type movements as well as various knee injuries from front lunges, pistols, and many other unilateral movements.

A good rule of thumb is this: if a particular exercise decreases stress in an area of the body that is involved in that movement pattern, then another joint involved may receive an even greater amount of stress.

I'm sorry buddy, but no amount of single leg exercises will resurrect that leg

Claimed Benefit #3- Unilateral leg training balances any strength disparities between the left and right leg.

The Truth- If one leg is stronger than the other, it makes perfect sense to train one leg at a time.

In theory, by doing this, you will force the weaker leg to do equal work with the stronger leg, thus balancing out the strength discrepancy. Unfortunately, this “weak side rule” rarely balances anything.

In most cases, strength imbalances are caused by genetic factors or are nerve flow related. If genetics are causing a disproportion in your strength levels, there is nothing you can do except be aware of it and don’t push much beyond the weaker side’s capacity.

If your strength issue is caused by nerve impingement or decreased nerve flow, go to a healthcare professional and have the problem addressed.

I have seen good soft tissue practitioners work wonders at freeing up nerve flow, allowing strength to return to the weaker side.

This is to be worn by all "strength" coaches who exclusively promote the single leg theory. They come in small and medium. Please send me your size and I send one right over to you

Well, those are the big reasons why the single leg movement is gaining considerable momentum in the industry lately. As you can see from my rebuttals, I disagree with the pundits once again!

However, this doesn’t mean that I don’t prescribe single leg exercises for my clients.  It just means I don’t find them to be superior to bilateral movements. Here is how single leg exercises fit into my routines:

For assistance work- After knocking off a big lift (i.e. squats, deads, etc), I find single leg exercises to be great for supplementary work. Just be sure to emphasize a big lift first, especially if your goals are size and strength.

2) For individuals who are more concerned with fitness then strength- Some people don’t care about getting big and strong; they just want to be in great shape.

These people simply don’t need to take the time to dedicate themselves to learning how to do big lifts properly and safely. In these cases, unilateral movements (which are generally easier to perform) will provide an adequate training stimulus for these trainees to accomplish their goals.

3) For inflexible individuals- If you are too tight to pick an implement off the ground or lack the mobility to squat down to at least a parallel position without rounding your spine, you should (for your own safety) be sentenced to a life of single leg movements until you develop the necessary flexibility.

Even if you fall into my previous “fitness enthusiast” category, it would still be well worth your time and effort to develop an optimal level of flexibility. Get to it!

4) For those with pre-existing back injuries- For individuals with disk issues (i.e. herniations, bulges, degenerations, etc.), risk-to-reward should be considered before including any movements into their training routine. Since unilateral leg exercises have the potential to stress the lumbar spine less than bilateral leg movements do, they get the edge for individuals with back injuries.

I hope this clears up the all of the confusion on this topic: single leg exercises have their place, but in most cases, they should not be the nuts and bolts of your strength training routine.

Dedicated to your success,

John Alvino

Comments

  1. says

    I’m amazed at how the tide of silly ideas wash over the fitness community, sweeping critical thinking out to sea (how long until we look back, heads shaking, at “stability” exercises?)

    Much as I LOVE squats and deadlifts, I fall into the “spinal problem” category. In fact, my doctor flipped out when I told her I was doing 350 lb. deadlifts (so I haven’t told her that I’m up to 475).

    Sadly, it’s not uncommon for me to do a heavy deadlift set and then need to immediately decompress my spine (oh, grade 1 spondy with pars defect — a.k.a. broken L5). So, I’ve been doing more weighted hip thrusts and unilateral work.

  2. Chris S says

    John,

    This is a great post and echoes what I have discovered in my own training. I train pistol squats very often and have built a lot of strength and work capacity on them.

    How often you feel this great measure of strength and motor control can be trained throughout the year, without suffering the detriment to the knee or other structures you spoke about in the article. I like to train high frequency and thus far have had no knee issues.

    Keep up the great work.

    Thanks,

    -Chris

    • John Alvino says

      @Chris S: Hey Chris, for you, the only thing I would be concerned with is the knees. If you have no pre-existing issues, use perfect technique and are quite strong, you can get away with a higher frequency of pistols. That being said, I would still limit them to three times per week. Especially if you are active outside of the gym

  3. says

    Good post John, and what’s really getting old is the whole “best exercise for (fill in sport)” when it’s obvious that athletes, in most all sports, have historically used the big lifts (on both feet) to get stronger, as well as many other lifts or exercises.

    This whole either/or is all marketing hype, and it’s sickening … and limiting because it makes folks feel as if they have to choose sides. Perry Rader once wrote that if a man only had access to DBs and worked up to doing one-legged DB deadlifts on a raised platform with 80lbers, he’d be a pretty strong and developed man. So, why the need to force people to choose?

    Personally, I absolutely HATE lunges …

  4. Holly says

    You are a health of knowledge. It makes so much more sense now that you put it that way. I like most people have a weaker side and can see how one would definately benifit over the other. Thanks John!!!

  5. says

    I just wanted to make one point for single leg exercises here. First, though I personally believe, why not perform both unilat and bilat exercises if you can. They both have benefits that they other can’t do so might as well do both. For single leg though, I find that the load more directly goes to the lower body. With bilat squats and deadlifts, the core will always be the limiting factor. I think it is good to train it, but single leg exercise may put more of the load on the leg and less through the core. But I do agree with most of the points you made.

    • John Alvino says

      @Mike D: Hey Mike, doing both was the point of this post. I disagree that the core will always be the limiting factor. But if it was for you, why not train it? If you were trying to isolate the legs, you would be avoiding training the weak link. I’m sure you could see how that wouldn’t be the best idea.

      Well anyway, thanks for sharing your opinion

  6. says

    Hi John, my experience as a trainer is that sometimes mobility/flexibility issues might be the reason to avoid bilateral lifts (at least for a while). For example, a lack of ankle dorsiflexion on one side causes some degree of lumbar rotation while squatting (not a good thing….). Same thing with deadlifting, a “stiff” hamstring on one side often leads to lumbar rotation. Some of my clients deal with these issues and a simple solution has been (in addition to implementing mobility work) to replace the big lifts with unilateral movements. Once these issues have been corrected, they are “cleared” to start squatting and deadlifting again. Having said that, these lifts are still the cornerstone of any good strength training program and should not be excluded unless there’s a really good reason for that!

  7. Jess says

    Great post John! I prefer bilateral exercises bc sometimes my knees or lower back bother me but I like when you incorporate single leg exercises in our routines! I always look forward to your writing bc I learn so many things that I would probably never look into.

  8. Gina says

    Great stuff John! Since I’ve been reading your blog, I read less and less of other blogs. I’m starting to see all of the B.S. out there. Thanks for spreading the truth

    • John Alvino says

      @Gina: Hey G, you’re welcome, I will not comment about other blogs but you can definitely count on me for giving you the real deal and not a bunch of BS or marketing hype

  9. Alan says

    But what if you only have one leg? I lost my right arm and leg in a motorcycle accident years ago and have no choice in the matter. The trick is designing a squat or deadlift I can safely perform. I does cause other imbalances in the body that are problematic though. I can easily tear neck and shoulder muscles if I’m not careful. I guess we all need to do the best with what we have. Thanks for the post.

  10. says

    Awesome post. I never knew that unilateral leg movements could result in such severe injuries…heck, I didn’t even know that there are strength coaches out there who believe that single leg movements are superior to the almighty barbell squat!

    • John Alvino says

      @John Phung: Hi John, glad you enjoyed the post. Single leg movements can definitely stress the knees, especially if one attempts to load them with heavy weights. That is why I prefer to use them for assistance work

  11. Richard says

    This is some really good information, thank you!
    It’s time to implement some pistols. You should make a warrior program!

    I’ll be the first one to buy it!

    Richard

  12. Alex says

    You are totally right !!
    It is difficuld to sell the good old basics, so people have to come up with these stupid new theories.. it reminds me of stability training too :)
    I have to agree in terms of joint stress, i have a very bad knee (Ligament transplant), im able to squat really heavy, balls to the floor, but i cant do 1 single pistol squat on my bad leg..
    Its ok to use them, but they shouldnt be the focus.. wanna get strong, use the exercise in wich you can use the heavier load, period.

  13. Dave says

    Great post! I am researching single leg stuff. I have been doing a lot of single (and double) leg burpee’s. I like that it takes way fewer reps to exhaust myself(legs and heart), and the balancing act which taxes the fast twitch fibers and feet muscles?, seems to work well for me too. Thank you for your insightful and educated discourse. Im glad i found your site. I often don’t give enough thought to loading but I do notice that my knees HATE single leg squats, so I avoid those in lieu of perfect form split lunges and stretch my legs adequately AFTER working them. Thanks again!!

    • John Alvino says

      @Dave: Hi Dave, you’re welcome and I’m glad you enjoy the site! I would suggest that you do a blend of bilateral and unilateral training in your routine and definitely don’t do any movement that causes joint pain. Thanks for sharing your experiences with us!

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