Bilateral - having or relating to two sides; affecting both sides
Unilateral - of, occurring on, or affecting one side only.
Bilateral means having or relating to two sides; affecting both sides. Unilateral refers to something occurring on or affecting one side only. Unilateral exercises involve training one limb at a time, like a single-leg pistol squat, while bilateral exercises engage both limbs simultaneously, such as a barbell back squat. Bilateral exercises are often prioritised for their hypertrophy and strength benefits—and for good reason. You can certainly lift more weight using both limbs rather than one. More weight equals more gains, right?
Well, maybe not. Unilateral lifts may actually place more stress on the loading lever than bilateral lifts, and they can also produce fascinating nervous system reactions. This blog explores why unilateral training deserves more attention, the benefits it offers, and how to incorporate it into your routine.
How Much Strength Do You Really Need?
Firstly, we need to ask - How much strength is enough? Is there a point where chasing maximal strength begins to interfere with other physical qualities, such as mobility, flexibility, coordination, lightness and awareness? Do you really need a 200kg back squat? What are you sacrificing to maintain such a feat of pure strength? Could strength development follow an inverse U-curve, where beyond a certain threshold, it begins to hinder functionality rather than enhance it? I think the challenge lies in finding a balance. And within that balance, particularly referring to the promotion of strength, can we find ways to propagate strength in terms of relative (in relation to something else) rather than absolute (on its own). With this in mind, the philosophy to my training approach is always - How do I work towards physicality that expands many areas, with large carryover benefits? One way I have found that is easy to implement and holds these attributes is Unilateral patterns and movements, and in my experience, this kind of work really encourages that relative strength I deem important and would encourage others to chase too...
A Few of My Experiences With Unilateral Training
During the COVID-19 lockdown, I set out to achieve a one-arm chin-up (OAC). With no gym access, it was the perfect opportunity to focus on a goal that required minimal equipment. My training revolved entirely around unilateral exercises - mixed grip chin ups, archer chin-ups, assisted one-arm pulls, and OAC negatives.
By the time gyms reopened, I was training with a friend and we decided to test our max chin-up numbers. To my surprise, I hit 24 chin-ups in one set (these were proper chins too, no Mark Whalberg reps)—far exceeding my previous best of ~15. I hadn’t been training for max reps at all, in truth I had actually never done a set with greater than 5 reps in all the time I was training for the OAC, but focusing on unilateral strength patterns provided strength and muscular endurance gains that inadvertently helped me break through my plateau and achieve unexpected bilateral gains.
The same applied to my leg training. By shifting from barbell back squats to heavy single-leg pistol squats with a kettlebell, I increased my back squat max by 25kg in just two months - without doing any back squat training at all...
It wasn’t long after this that an obsession with kettlebells took hold. At the time, I was training a lot of BJJ and wanted a strength routine that complemented it - something simple, efficient, and adaptable. I needed a training method that I could do anywhere, without a gym. For months, I had two kettlebells rolling around in the back of my van; every time I took a corner, it sounded like one of them was about to punch a hole through the side.
My training revolved heavily around Pavel Tsatsouline’s Simple and Sinister methodology: 10×10 single-arm kettlebell swings and 10×1 Turkish get-ups. This minimalist approach fit perfectly with my needs - quick, effective, and brutally efficient. But, as the underlying point of this blog goes, the training was solely unilateral.
I also turned to kettlebells out of necessity. An injury left me with painful elbow tendinitis, fortunately I found that integrating kettlebell swings and get-ups into my routine was not only therapeutic but allowed me to train without exacerbating the inflammation. The combination of swings, get-ups, single-arm presses, and clean-and-presses built incredible strength, at the time i wasn't thinking about 'oh, i am doing all unilateral work now', but on reflection, I can see the link to why I can remember packing on both size and power during this period. It came to fruition when I trained with a friend, this time we went for 1RM on the military press. low and behold, there was significant strength gains made here too. Repping 70kg overhead was a big acheivement for me, and it was that much sweeter as I hadn't even tried to get it - it was merely a benefit from all the kettlebell work i was doing.
Regarding my anecdotal evidence, it doesn't stand for much, but before we get into the science of why I feel Unilateral training is a good idea to implement at least some of your time too, I’ll propose this paradox: How many people do you know who can bench their own body weight? For example, if I weigh 80kg, can I bench 80kg? The numbers will be relatively low—it’s a challenging feat, particularly for the average person who does not lift. Now, how many people do you know who can perform a strict one-arm push-up with proper technique? Again, the numbers are low. It’s difficult.
But here’s where it gets interesting. I’d wager that most individuals capable of a strict one-arm push-up could also bench their body weight. However, I highly doubt that the die-hard bench pressers—those who can press their body weight or more—would fare well in a one-arm push-up.
Don’t believe me? Find out for yourself. See where you stand and put it to the test.
In my eyes, strength isn’t just about how much you can lift—it’s about what you can do with it. And when you start viewing strength through that lens, some of the conventional lifts we idolise don’t seem quite as impressive as we once thought. And certainly do not compliment to others as well. Remember; Biggest bang for your buck - and to the old adage, i tip my hat - train smarter, not harder!
The Motor Learning Benefits of Unilateral Training
Unilateral exercises are more than just strength builders - they challenge the brain and nervous system in unique ways. Training one side of the body forces the nervous system to create new pathways, improving motor learning, coordination, and body awareness. Because unilateral movements in most cases require increased balance and stability, they demand greater control and engagement from muscles, ligaments and tendons. This adds complexity to your training, which may also stimulate the dopamine system as you tackle and overcome new challenges.
Attempting a one-arm push-up or pull-up, for example, isn’t just about brute strength. It’s a skill that requires determination, consistency, and technique. These movements force your brain and body to problem-solve, creating a sense of accomplishment that carries over into other areas of life.
The Science: Bilateral Deficit and Cross-Education Effect
Unilateral training provides unique physiological benefits, including the bilateral deficit and the cross-education effect. The bilateral deficit occurs when the combined force of two limbs working separately is greater than when they work together. For example, a study by Bottan et al. (2020) showed that unilateral training increased force output by 10%, compared to just 3% with bilateral training.
The cross-education effect refers to how training one limb can indirectly strengthen the other. Research shows that training one arm can increase strength in the opposite arm by 4%, while training one leg can yield strength gains of up to 7% in the untrained leg. This effect is particularly useful for injury rehabilitation, as it helps maintain balance, symmetry and strength in the side that is out of action.
Why You Should Include Unilateral Training
Unilateral exercises offer benefits that bilateral movements alone may not provide. They have amazing crossover benefits that can enable the break through of plateaus in bilateral lifts, they can enhance balance and stability - particularly important when you understand one of the greatest hazards we encounter for our ageing population is the risk of falls, and how detrimental these are in the elderly. Unilateral patterns promote greater mobility through an increased range of motion (look at the depth of a squat in a full ROM pistol in comparison to a barbell back squat). Unilateral training is also ideal for injury recovery and boosts neuro-muscular activation by engaging stabilising muscles and nervous system pathways.
Practical Applications of Unilateral Training - and how to implement!
Incorporating unilateral training doesn’t mean abandoning bilateral lifts altogether. Instead, it’s about finding the right balance and tailoring your routine to your goals. Start small by beginning with regressions of unilateral movements, such as assisted one-arm chin-ups, archer push-ups, or split squats. Focus on form to ensure safety and effectiveness, and integrate unilateral exercises strategically as accessory movements to complement bilateral lifts. You can also experiment with minimal equipment; often, a kettlebell, pull-up bar, or bodyweight is all you need for effective unilateral training. Below, I have included a table of my personal favourite unilateral lifts, and a training blog implementing unilateral lifts.
If you’re curious about how to get started or want personalised guidance, I offer 1-on-1 coaching that integrates a lot of unilateral training into a well-rounded program. Get in touch, and let’s explore how you can unlock some GAINZZZ!
(1) Gonzalo-Skok O, Tous-Fajardo J, Suarez-Arrones L, Arjol-Serrano JL, Casajús JA, Mendez-Villanueva A. Single-Leg Power Output and Between-Limbs Imbalances in Team-Sport Players: Unilateral Versus Bilateral Combined Resistance Training. Int J Sports Physiol Perform. 2017 Jan;12(1):106-114. doi: 10.1123/ijspp.2015-0743. Epub 2016 Aug 24. PMID: 27140680.
(2) Green LA, Gabriel DA. The cross education of strength and skill following unilateral strength training in the upper and lower limbs. J Neurophysiol. 2018 Aug 1;120(2):468-479. doi: 10.1152/jn.00116.2018. Epub 2018 Apr 18. PMID: 29668382; PMCID: PMC6139459.
(3) Botton CE, Radaelli R, Wilhelm EN, Rech A, Brown LE, Pinto RS. Neuromuscular Adaptations to Unilateral vs. Bilateral Strength Training in Women. J Strength Cond Res. 2016 Jul;30(7):1924-32. doi: 10.1519/JSC.0000000000001125. PMID: 26348920.
(4) Saeterbakken AH, Fimland MS. Muscle activity of the core during bilateral, unilateral, seated and standing resistance exercise. Eur J Appl Physiol. 2012 May;112(5):1671-8. doi: 10.1007/s00421-011-2141-7. Epub 2011 Aug 30. PMID: 21877146.
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