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I’ve made a career out of analyzing the biomechanics of resistance exercises. But I’m not just an arm-chair expert; I take pride in the fact that I’m always hitting the gym hard and experimenting with different exercises. When I travel, I love attending local commercial gyms and even training in hotel gyms as it causes me to try new things in my training. I’ve mastered most implements and can achieve a great workout with bodyweight, dumbbells, kettelbells, resistance bands, barbells, or machines.

But all of this might not be necessary. A brand new study was just published ahead of print showing that just flexing your muscles throughout a full range of motion was equally effective as traditional weight training (but strength gains were greater in the high load condition compared to the no load condition).

This isn't just for show - it actually builds muscle!

This isn’t just for show – it actually builds muscle! That’s why Spencer does it so much.

I was actually one of the peer-reviewers for this article, so I’m quite pleased that it was accepted. I’ve often wondered about this and even planned out a study comparing glute squeezing versus weight training on glute hypertrophy around two years ago. There are a few papers which have already shown promising potential with voluntary contractions (HERE and HERE are a couple). As you can see, this study was right up my alley.

The acute and chronic effects of “NO LOAD” resistance training


  • Contracting a muscle through the full range of motion with no external load increases muscle size comparable to that of high load training.
  • High load training produced larger increases in 1RM strength and muscle endurance compared to contracting through the full range of motion with no external load.
  • Muscle growth can occur independent of the external load provided sufficient tension is produced by the muscle; however, strength is proportional to the load being used and the modality of exercise being performed.


The purpose of the study was to remove the influence of an external load and determine if muscle growth can be elicited by maximally contracting through a full range of motion. In addition, the acute physiologic and perceptual responses to each stimulus were also investigated. Thirteen participants completed 18 sessions of unilateral elbow flexion exercise. Each arm was designated to either NO LOAD or HIGH LOAD condition (70% one repetition maximum). For the NO LOAD condition, participants repeatedly contracted as hard as they could through a full range of motion without the use of an external load. Our results show that anterior muscle thickness increased similarly from Pre to Post, with no differences between conditions for the 50% [Pre: 2.7 (0.8) vs. Post: 2.9 (0.7)], 60% [Pre: 2.9 (0.7) vs. Post: 3.1 (0.7)] or 70% [Pre: 3.2 (0.7) vs. Post: 3.5 (0.7)] sites. There was a significant condition × time interaction for one repetition maximum (p = 0.017), with HIGH LOAD (+ 2.3 kg) increasing more than the NO LOAD condition (+ 1 kg). These results extend previous studies that have observed muscle growth across a range of external loads and muscle actions and suggest that muscle growth can occur independent of an external load provided there are enough muscle fibers undergoing mechanotransduction.

Additional Info

The training period involved 18 sessions – 3 sessions per week for 6 weeks. Each subject performed both protocols; one arm was used for no load and the other arm was used for high load. The no load condition had the subjects moving their arms into elbow flexion and extension while attempting to maximally contract their biceps throughout the range of motion. They experienced EMG biofeedback which encouraged them to flex as hard as possible throughout the workout. They performed 4 sets of 20 reps with 30 seconds rest time in between sets. This seems like it would be surprisingly challenging. The high load condition involved the performance of a dumbbell curl with 70% of 1RM for 4 sets of 8-12 reps with 90 seconds rest in between sets. Progressive overload was utilized.

My Take

Do gym owners and equipment manufacturers need to close up shop? Should personal trainers start seeking other jobs? Can advanced lifters ditch the weights and continue to build muscle by posing in front of the mirror? Not so fast…

First, all good scientists should be patient and wait for research to be replicated before reacting strongly. Second, strength and function are important, not just hypertrophy. Third, this study examined beginners; the possibility exists that experienced lifters need more advanced stimuli. That said, I will state that the untrained versus highly trained subjects limitation is often overhyped. Forth, the study just examined biceps, and biceps are easy to contract. Some muscles like biceps and quads seem quite easy to contract, whereas others such as delts, lats, and hams aren’t as easy to contract through a full range of motion. There are also subdivisions of muscles which aren’t easy to contract voluntarily with no load. Interestingly, the authors mentioned that often the no load arm wouldn’t elicit high levels of EMG activity until end range contraction was reached, whereas with adumbbell it would experience more consistent high levels of EMG activation. For this reason, I wonder if one could just stretch and then flex a muscle intermittently and experience similar hypertrophic results as what was seen in this study.

What this study does show, however, is that posing in bodybuilding provides an excellent muscle-building stimulus. Technically, posing in and of itself wasn’t examined as the no load condition performed 80 maximum voluntary contractions in around 5-6 minutes. But we can indeed conclude that one could maintain and possibly even build muscle without any weights during somewhat brief periods of time away from the gym. In addition, it has ramifications for the entire world and is important for fields of research pertaining to fitness, rehabilitation, aging/frailty/sarcopenia, and more. I hope the study gets the attention it deserves and attracts follow-up research from my fellow sports scientists.

Now I have good reason to do more of this...

Now I have good reason to do more of this…


  • Alex says:

    Really excited about the follow up studies. Not because I’m a lazy ass but because this could be a valuable alternative to keep in shape during travelling if one can’t have access to a gym (like broke af students for instance).
    Thanks for sharing!

  • Pete says:

    I remember reading Pavel Tsatsouline writing (might have been the first “Power to the People”) that you could conceivably see strength and size increases just from generating full body tension without a load — basically, flexing every muscle in your body that you could.

    But he also thought there would be a limit to strength increases since you weren’t conditioning the joints and connective tissues to handling higher loads. Obviously, one study doesn’t prove or disprove things either way, but it does jive with the findings so far.

    There’s also the issue that you brought up, that some muscles are pretty hard for inexperienced trainees to properly flex. It’s hard enough to get some people to properly engage their lats with pullups and rows, I can only imagine that taking away the load would make it that much harder.

    And heavy loads have a tendency to provide a marvelous “reality check” when it comes to muscle engagement. Powerlifters quickly learn that you’re leaving lbs on the table if you don’t engage your abs, lats, and glutes during a max effort squat. Same with leg drive during the bench. Get rid of the load, and you might lose that awareness of how everything’s interconnected.

    • Duff says:

      I’ve played around a lot with this style of training (sometimes called Dynamic Tension or Dynamic Visualized Resistance training) and I agree with all your concerns. I think it can be a useful adjunct to traditional strength training, being low-impact and therefore inherently quite safe especially for people with injuries. It can also increase body awareness in useful ways. But it also has limits, especially with all the things you mentioned: development of tendons and joints, learning specific movement patterns, and activating specific muscles being more challenging than others. That said, I have found it a useful thing to practice from time to time, and an interesting complimentary form of training with both fitness and even psychological benefits.

  • Brad says:

    Hey brother,

    Long time no talk. I remember having a discussion with Stu Phillips where he had mentioned that strength comes from practice. So the No load people in this trial may not have strength improvements due to lack of practice… adding in some practice lifts throughout the protocol may have made the differences in strength less apparent, but that’s just me guessing.

  • claudia says:

    Awesome thank you

  • Jason says:

    This is extremely interesting!!
    I’m glad I learned about you from Alan Aragon; your blog is the tits.
    Between you, Brad, and Alan, it’s like the trifecta of getting swole science masters.

  • Jason says:

    Maybe we should all just get TENS machines and set them up to high….those things will make muscles contract. No weights needed. Get swole watching netflix

  • Rachel says:

    Two things come to mind when I read this article. The first is my personal experience when adding movements contracting my glutes for extended periods of time (focus on clenching as tight as possible, for as long as possible…). I typically go from a sumo squat, then slowly stand/contract and hold, hold, hold. I’ve been doing this for the past three months or so and its been a game changer for me. I have trained for bikini comp the past two years and I “feel” this the rest of the day. Not many movements create soreness and that booty pump limited to my glute area (no quad, ham or lower back) as simply contracting and hold. The second is when I think about competition posing classes… Last year I attended group posing for 2 hours every Sunday from Feb – Aug. The group size ranged from around 10 – 40 people competing in all different NPC divisions (men+women) from beginners to IFBB Pros. The first hour, was division-specific posing, then the last 30 minutes was dedicated to everyone getting in lines, get into a pose, hold for 1-2 minutes, directly switch to another pose (5 seconds switch), then hold again 1-2 minutes. Not one person left without feeling like they just trained, swole as all get out, when leaving class. Thank you for the article Bret, looking forward to more on this subject.

    • Duff says:

      Interesting. It’s been my experience that when I haven’t been able to get a particular muscle to grow, I usually also can’t consciously flex it very hard. Just practicing deliberately flexing the muscle as hard as possible a couple times a day even seems to help me. Just my broscience 2c, but doesn’t take very long to do.

  • Bret, great article.

    First off, I had a question: I want to start implementing resistance bands in my and my clients’ training. What brand/kind do you think is best? I am contemplating getting these power bands (http://www.muscle-power.nl/mp1401-power-bands?gclid=CIvgv8HBzM0CFYcp0wod3vMH8Q), because I learnt the resistance curve is very linear (as opposed to abruptly increasing when you get over a ‘sticking point’ of stretch).

    Onto the article: I think 2 more reasons why training with weights is so valuable, is because it offers feedback in 2 ways:
    – you can measure performance, which let’s you know whether you’re progressing with your current program.
    – it offers motivation by seeing your weights get heavier and heavier over time.

    Both of these aren’t possible with EMG-training.

    Thanks for the write!

  • icdw says:

    Hi Bret.
    Amazing finding really.
    But isn’t this the same as what old-time strong-man Maxick practiced and advocated? Might this mean that he was onto something real?

  • Jeffrey says:

    I remember a study that showed that increases in size occur on the contralateral side even without training or contraction presumably by some hormonal or neurological influence. To be completed, this study should have had a control group that did curls on one side and nothing on the other. Thanks for the review.

    • Joe says:

      Great point, Jeffery. I do think this article and study proposes a nice way for somebody who is limited in some capacity (traveling, injury, etc.) to get a baseline amount of mechanical tension on their muscles, but I do think the study design was a limiting factor due to the effect that unilateral training has on the non-trained arm like you mentioned. I dug around and found this study in the Journal of Applied Physiology that lends so credence to strength gains in the non-trained arm: http://jap.physiology.org/content/101/5/1514.

      It’s interesting to note that the study cites examples of nearly 43% increases in strength in the non-working arm relative to the working arm. In the abstract, the 1 kg of 1 RM gained in the non-working arm is VERY close to 43% of the 2.3 kg gained in the working arm.

      It’s worth noting that it is physiologically possible to get stronger without getting bigger, so while the strength improvements in the non-working arm might be explained by the work of the other arm, the size gains may be a product of the no load training entirely. Would love to see these results replicated with a better design, but kudos to the researchers for putting this theory to the test in the first place. Anyone who has ever done a posing routine or simply flexed their muscles for some serious ‘mirin time in the mirror could guess that there were probably some growth signals being sent simply based on how sore they were afterwards.

  • Duff says:

    Sounds like Charles Atlas’ old methods. Also a contemporary man named John Peterson advocates for this style of training, and he is reasonably big for a natural athlete.

  • Tom F says:

    Charles Atlas was right.

  • Floris says:

    i’ve read somewhere there is a crossover effect between limbs when training. if you train your right arm your left arm also benefits from this training. don’t you think this is a big confounder in this study?

    • Initially I did but the authors addressed this and they don’t think it’s an issue (and I believe them after checking the reference). Could have been an older Stu Phillips paper that addressed it though, my memory is failing me now.

  • Alejandro N. says:

    Hold on! Correlation doesn’t imply causation!

    Here’s a study in which participants strengthened BOTH calves from only training (stretching actually) ONE: http://www.ergo-log.com/stretchingrightcalf.html. If we apply this concept to the study above, then the NO LOAD arm could’ve grown because of the stimulus of the other HIGH LOAD arm.

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