The Benefits of Unilateral Training (Single Leg Exercises)

Single leg exercises are often some of the least liked in the gym -- but they should be a part of your routine. 

Here's why.

Symmetrical Aesthetics

If you are training to build muscle and improve the way you look, symmetry is something you should care about. I mean looking big is great, but looking big and symmetrical? 

That's what sets you apart from the crowd.

With that in mind, unilateral exercises are some of the most effective ways to eliminate asymmetries in the muscle size of the lower body. 

See, your body is smart, and although big compound exercises like squats and deadlifts technically train both sides of your body, they don't do so equally. If one side of your body is stronger than the other (which is the case for most people), then you will naturally compensate to make the movement easier.

And this often means subconsciously placing more load on your stronger side.  

As a result, asymmetrical muscle development is pretty common. But single leg exercises are your solution.

Because exercises like split squats and lunges predominantly load one leg at a time, they eliminate the potential for compensation. This has obvious implications for building a symmetrical physique.

As a note, when you first start performing single leg exercises, you will notice that one side is stronger than the other (this is entirely normal). Make sure to start all your single leg exercises on the weaker side, then match the number of reps on your stronger side.

This is a great way to even up asymmetries while ensuring an even amount of muscle growth between legs.

Greater Muscle Growth

While you should never change exercises every week, there is some evidence to suggest that implementing different variations that target the same muscle group will lead to better muscle growth than using just one or two variations [1].

If all your quad work comes from squats, leg presses, and knee extensions, you are loading the muscles in a somewhat similar manner between exercises (especially between the squat and the leg press).

But if you throw just one single leg exercise into the mix, you add another degree of variability into the program, which can increase muscle growth.

As a bonus, you don't even have to add in more training volume for this to yield a positive effect. Instead, all you need to do is reallocate some of the volume you are already performing to single-leg exercises:

For example, if your quad work looks like this:

• Squat 3 x 8
• Leg Press 3 x 10
• Leg Extension 3 x 12

You could replace two of the sets with split squats like this:

• Squat 3 x 8
• Leg Press 2 x 10
• Split Squat 2 x 10
• Leg Extension 2 x 12

If your leg routine is void of single leg exercises, give this a go to kickstart some extra muscle growth (just be ready for some serious DOMS that first session…).

Improved Athleticism

Most of us don't only train to look good but feel good too.

Considering this, single-leg exercises are a must. Split squats, lunges, and their many variations replicate athletic movements like jumping, sprinting, and bounding. As a result, they have a direct carryover to those activities, making you more athletic [2].

If you intend to become big, jacked, and athletic, single-leg exercises are an absolute must.

Less Systemic Stress

You can think of systemic stress as the total stress placed on your body during a gym session. This encompasses the stress placed on your joints and connective tissues, as well as the stress placed on your muscles.

In short, the greater your level of systemic stress, the harder it is to recover.

Taking this into account, those exercises that create the most systemic stress allow you to use the most absolute load, and therefore place the most load on your connective tissues.

Think squats, deadlifts, and their many variations.

While there is little to no scientific research on this topic, most people are aware of it. Think about the fatigue you accrue after a heavy set of squats. It is much more than a set of leg presses, even if the muscular fatigue is similar between the two.

As such, if you replace some of these exercises (or at least reallocate some of their volume) with their single leg variations, you can get the same muscular stimulus with significantly less systemic stress. 

This means faster recovery between sessions, which could increase long-term gains by the quality of your training sessions over the long term.

Plus, not feeling like you got hit by a truck after every leg session is nice too.

Enhanced Functional Capacity

While this is not something that all of you care about right now, it will be in the future.

Single-leg exercises improve balance and your capacity to perform activities of daily living, such as standing up from a chair, walking up stairs, and moving about the house.

As a result, they can also help reduce your risk of falls as you get older, while ensuring you maintain your independence wll into your golden years -- which, if you intend to be a lifelong lifter, is a pretty big bonus [3].

Best Single-Leg Exercises

Like most things, the "best" single-leg exercise will be dictated by your goals.

If you want to maximize muscle growth and eliminate asymmetries, exercises that take your joints through a larger range of motion are your best bet. This means Bulgarian split squats, front-foot elevated split squats, and front-foot elevated reverse lunges should be your first point of call.

Exercises replicating real-world movements are key if you want to improve your athleticism and functional capacity. This means reverse lunges, lateral lunges, walking lunges, and step-ups should be a part of your program.

Suppose you are simply looking to try something different and reduce systemic stress. In that case, any single-leg exercise is a good choice. I like barbell split squats, walking lunges, and Bulgarians, but it is really up to you.

Single Leg Training: Final Thoughts

Whether your goal is to build muscle, become more aesthetic, increase athleticism, or improve your day-to-day life, single-leg exercises must be part of your routine.

Next program you write, we want to see a heap of single-leg exercises thrown in the mix.

References:

1. Kassiano, Witalo, et al. "Does Varying Resistance Exercises Promote Superior Muscle Hypertrophy and Strength Gains? A Systematic Review." The Journal of Strength & Conditioning Research 36.6 (2022): 1753-1762.
2. Fisher, J., and M. Wallin. "Unilateral versus bilateral lower-body resistance and plyometric training for change of direction speed." J Athl Enhanc 6 (2014): 2.
3. Josephson, Micah D., and John G. Williams. "Functional-strengthening: A pilot study on balance control improvement in community-dwelling older adults." Montenegrin Journal of Sports Science and Medicine 6.2 (2017): 75.

A US study, conducted by Moore et al and published in the prestigious PLOS Medicine in late 2012 examined the relationships between leisure time physical activity levels, longevity and rate of mortality of 654827 individuals aged between 21-90 from America and Sweden and showed that exercise can indeed affect human life expectancy. In fact, the more exercise you do, the longer you live.

The world health organization recommends a minimum of 150 minutes per week of moderate-intensity exercise or 75 minutes per week of vigorous-intensity exercise or an equivalent combination of both for health benefits. Moore et al found that a high level of leisure time physical activity is associated with lower risk of mortality and a longer life expectancy compared to people who do no exercise at all. Leisure time physical activity is the activity OUTSIDE the context of job, housework, transportation and other essentials of daily living. Working hard at your job is NO substitute for real exercise.

The study found that any leisure time physical activity is beneficial to your longevity and reduces the risk of mortality. People did leisure time physical activities at any levels below the recommended minimum experienced an average gain of 1.8 years of life expectancy compared to people who did not exercise at all. Keeping activity levels at or slightly above the recommended minimum would further reduce the risk of mortality and increased average life expectancy by 3.4 years. Doing twice the recommended minimum amount of leisure time physical activity would give a 4.2 year gain in average life expectancy and doing 3 or more times the recommended minimum would give a 4.5 year gain. The amount of life expectancy gained as well the reduction in rate of mortality from doing exercise appeared to plateau at around 2-3 times the recommended minimum level. The trends described above applied to all age groups, genders, racial backgrounds, education levels and BMI groups in the people tested albeit with slight variations.

The study also found that the benefit of doing leisure time physical activity is more pronounced in former smokers, and people with a history of heart diseases and cancer. Obesity (BMI: 30+) was found to be associated with a lower life expectancy in all physical activity groups compared to those with a BMI between 18.5 - 29.9 (normal weight and over weight). Obese people who did not exercise lived 7.2 years shorter than people with normal weight (BMI: 18.5 - 24.9) who did at least the recommended minimum level of exercise each week. However, the interesting finding was that class I obese people (BMI: 30 - 34.9) who did more than the recommended minimum level of physical activity had an average of 3.1 years longer life expectancy compared to people with normal weight but did no exercise at all.

So what do all these mean? The study shows us that any leisure time physical activity is beneficial to your health and longevity. In fact, the more exercise you do, the better. A lack of physical activity is associated with an increased mortality rate and reduced life expectancy, especially when combined with obesity. The world health organization recommends a minimum of 150 minutes per week of moderate-intensity exercise or 75 minutes per week of vigorous-intensity exercise in order to be beneficial to health. Doing 2-3 times that amount has been found to be the most beneficial. Having an active life style is not just for the looks, your body will thank you for it.