Are Cheat Reps Beneficial? A Discussion of the Evidence and Implementation
by Jason Tremblay and Andrew Vigotsky
The word “never” is an evil word to use in sport science. How many times have you been told to never use momentum? To never break form? It’s common knowledge. But for the purpose of hypertrophy, is there a role in the training regimen of bodybuilders for cheat reps? So often we see bad form being chastised, but did the old timers like Schwarzanegger and Draper performing Cheat Curls in the original Golds Gym know something that we didn’t… Do cheat reps and momentum have their place in a bodybuilding regimen? Theory and evidence suggest that this may be the case.
Current hypertrophy theory suggests that mechanosensors convert mechanical energy into chemical signals which mediate anabolic pathways – ultimately creating an environment where more proteins are being synthesized than proteins being degraded.9 From this, one could surmise that muscle hypertrophy is based on the recruitment of as many motor units as possible in the target muscles, and achieving high firing rates in these motor units for a sufficient duration of time. 6, 8
In a recent article by Ogborn and Schoenfeld (2014), points were made in relation to Henneman’s size principle that may offer credence to the argument for including momentum in hypertrophy training. 5 The gist of Henneman’s size principle is that motor units are recruited in an orderly manner. Lower intensity tasks will invoke smaller motor unit activation, while higher intensity tasks will invoke a full spectrum of motor units. Ogborn and Schoenfeld noted that this principle discounts the role of fatigue and its ability to impact motor unit recruitment.
How could this occur? As fatigue builds up, force decreases. In order to sustain force output to get through repetitions in an environment of fatigue build-up, Loenneke (2011) theorized that we must recruit higher threshold motor units. 4 Thus, lower intensity training may be able to recruit a full spectrum of motor units as well. 2
In a physiological environment of high fatigue, being able to sustain force output and continue performing repetitions appears to be of value for hypertrophy. Therefore, there is a valid theoretical basis for performing cheat reps at the end of a set. This thought process also jives well with Arandjelovic (2013).
Although often perceived as counterproductive, “cheating”, at least in the case of a dumbbell lateral raise, allows the lifter to safely lift more weight, which increases the torque of the target muscles despite the increase in momentum. Of course, one can overdo this by “cheating” too much, so using moderate momentum (57.5º/s) seems to be ideal for safely increasing training stimuli and the resulting hypertrophic response, or at least hypothetically as per Arandjelovic’s 2013 complex modeling paper. 1
As coaches, we must not only consider evidence, but also practical implications of said evidence. We have presented both physiological and biomechanical arguments in favor of cheat reps – now let’s investigate methods of implementing cheat reps during program design.
It is easy to see why coaches, trainers, and trainees have frowned upon using momentum during lifting. When done incorrectly, it just looks bad, and depending on the situation, it may significantly increase the risk of injury. 9 When making important program design decisions, such as whether to integrate cheat reps or not, it is important to look at them in the context of risk vs. benefit. Does the risk of injury from performing cheat reps outweigh the benefit of potentially recruiting more high threshold motor units, accumulating more fatigue, and increasing torque on the target muscle? In our opinion, the answer to this question depends heavily on the exercise – because clearly, using momentum on a lateral raise isn’t the same as heaving a heavy dumbbell around while performing some single arm rows, which is why we present to you four rules to effectively and safely reap the benefits of utilizing cheat reps.
Rule #1 – Primarily use cheat reps with isolation lifts. The lighter loads and less degrees of freedom should serve to decrease the risk of injury and offer a safer platform to reap the benefits of this intensity technique.
Rule #2 – Don’t over do it! Arandjelovic (2013) suggests using moderate momentum to safely increase the stimuli.1
Rule #3 – Don’t cheat with heavy axial loads… Exercises that require a stable spinal column aren’t conductive to cheat reps, which include the exercises listed below (e.g., squats and deadlifts).
Rule #4 – Confine cheat reps to a limited number of sets per workout, as training to muscular failure too frequently may lead to burnout.
As with any rule, there are exceptions. Lifters should utilize good form with cheating, for example, push pressing the last couple of reps on military presses or swaying a bit with the last couple of reps on chin ups. Below are some exercises and how we categorize them with regards to cheat reps.
- Conductive to cheating include: curls, lateral raises, cable tricep extensions, front raises, and rear delt raises.
- On the fence with cheating include: one arm rows, lat pulldowns, bent over rows, shrugs, seated rows, chest supported rows, chins, military press
- Not conductive to cheating include: squats, deadlifts, lunges, good mornings, back extensions, hip thrusts, dips, bench press, power cleans, power snatches, swings, jump squats
As you can see, it’s safe to cheat on back exercises that involve pulling or rowing, but we do not recommend cheating on complex movements or movements that involve loading the spinal column. After years of chastising the use of momentum during exercise, we leave you with this classic:
“The last three or four reps is what makes the muscle grow. This area of pain divides the champion from someone else who is not a champion. That’s what most people lack, having the guts to go on and just say they’ll go through the pain no matter what happens.” – Arnold Schwarzenegger
Maybe success does leave clues after all…
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Note: This article was originally authored and published on bretcontreras.com in 2014
- Arandjelović, O. (2013). Does cheating pay: the role of externally supplied momentum on muscular force in resistance exercise. European journal of applied physiology, 113(1), 135-145.
- Burd, N. A., West, D. W., Staples, A. W., Atherton, P. J., Baker, J. M., Moore, D. R., … & Phillips, S. M. (2010). Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men. PloS one, 5(8), e12033.
- Faigenbaum, A. D., & Myer, G. D. (2010). Resistance training among young athletes: safety, efficacy and injury prevention effects. British journal of sports medicine, 44(1), 56-63.
- Loenneke, J. P., Fahs, C. A., Wilson, J. M., & Bemben, M. G. (2011). Blood flow restriction: the metabolite/volume threshold theory. Medical hypotheses, 77(5), 748-752.
- Ogborn, D., & Schoenfeld, B. J. (2014). The Role of Fiber Types in Muscle Hypertrophy: Implications for Loading Strategies. Strength & Conditioning Journal.
- Schoenfeld, B. J. (2013). Is There a Minimum Intensity Threshold for Resistance Training-Induced Hypertrophic Adaptations?. Sports Medicine, 43(12), 1279-1288.
- Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. The Journal of Strength & Conditioning Research, 24(10), 2857-2872.
- Wernbom, M., Augustsson, J., & Thomeé, R. (2007). The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans. Sports Medicine, 37(3), 225-264.
- Zou, K., Meador, B. M., Johnson, B., Huntsman, H. D., Mahmassani, Z., Valero, M. C., … & Boppart, M. D. (2011). The α7β1-integrin increases muscle hypertrophy following multiple bouts of eccentric exercise. Journal of Applied Physiology, 111(4), 1134-1141.