by Bret Contreras May 06, 2014
A potentially game changing study has just been published. It may change how you perform your exercises forever. Or it may not. Let’s have a look.
The study titled “the efficacy of incorporating partial squats in maximal strength training” is about combining partial and full reps in your training. The debate on whether training with a partial range of motion (ROM) has any benefits compared to training with a full ROM has been going on for decades.
One reason many people have trouble understanding the effects of ROM is because they think ROM is equal to the distance a weight or body part travels. It’s not. ROM is equal to the amount of degrees a joint flexes. Look at the illustration of elbow flexion ROM below.
Now that we’re clear on the definition of ROM, here’s the Cliff notes on the current state of the research on full vs. partial ROM training.
Note that all the above research compared training exclusively with a full versus a partial ROM. Competitive bodybuilders, powerlifters and to some extent Olympic weightlifters still regularly train with partial reps, but they all perform partials in addition to full reps. This is where the new study comes in.
Bazyler et al.  compared advanced trainees with an average squat of 324 pounds (147 kg) on a program of either 6 sets of full ROM squats (group F) or 3 sets of full squats and 3 sets of partial squats (group FP). At the end of the program, the group performing both partial and full squats developed more strength and more power than the group that always used full ROM.
“There was a trend for FP to improve over F in 1-RM squat (+3.1%) 1-RM partial-squat (+4.7%), isometric squat peak force allometrically scaled at 120° (+5.7%), and impulse scaled at 50 ms, 90 ms, 200 ms, and 250 ms at 90° (+6.3 to 13.2%,) and 120° (+3.4 to 16.8%).”
Case closed: using both provides the best of both worlds, right? Not so fast. A few caveats are in order.
Ok, recap: the results in favor of using both partial and full squats instead of just full squats to develop strength and power in the squat are questionable. Theoretically, however, it makes sense that incorporating partial squats increases power development. Partial squats allow for far greater power production than full squats . If I ask you to jump, you will intuitively do a partial squat before jumping. No one sinks down into a full Olympic squat, ready for take-off.
When the results of a study are unclear, we need additional research. Fortunately, Bazyler et al. weren’t the first ones to study combined full and partial rep training. Massey et al.  compared groups bench pressing with an equal number of sets of either full reps or a combination of full and partial rep sets. Although the difference in strength gains were not statistically significant, the full rep group gained 25 pounds on their bench press compared to just 16.5 pounds for the full+partial group.
The authors replicated this study and found the almost exact same strength increases in both groups. This time, the strength difference was statistically significant: the full ROM group gained more strength than the full+partial ROM group .
These studies on the bench press provide strong evidence against the use of partial bench pressing. However, the subjects in Massey’s bench press studies were all only recreationally trained. As you read earlier in this article, advanced trainees may benefit more from the use of partials than beginners. In athletes, variable ROM training for the bench press improved power production even though it did not increase strength gains compared to regular full ROM training . This corresponds with the findings by Bazyler et al. The subjects in the full+partial rep group gained less isometric strength in the sticking point of the squat, but their dynamic squat strength improved more because they became more explosive and could push through the sticking point better.
Here’s where it gets really interesting. The diets of the subjects in this study were not controlled. As a result, the average body fat percentage in the full squat group fell by 10.3%. Body weight did not change in either group and body fat percentage did not change significantly (-5.3%) in the full+partial group. The only way body weight can remain stable while fat percentage decreases is by gaining lean mass. So the full squat group must have gained more lean body mass than the full+partial group. I emailed the corresponding authors about this, since they did not discuss this in their article, but I have not received a response.
Full reps have several advantages over partial reps to induce muscle growth. Full reps activate muscles along their entire length (with the right exercise selection at least) . Stretching a muscle under load is a strong stimulus for muscle growth. It results in the addition of sarcomeres in series and in parallel, basically creating a thicker and longer muscle [9, 11]. The addition of sarcomeres in series is also why heavy weight training over a full ROM increases muscle length while stretching does not increase muscle length.
In in vitro muscle cells, animals and bio-artificial muscles, the combination of muscle activation and stretching has been shown to strongly increase protein balance, anabolic gene expression, anabolic hormone signaling – particularly insulin-like growth factor-1 and mechano growth factor – and muscle growth [9, 13-18]. Basically, stretching a muscle or activating it is a stimulus for the muscle to remodel itself and prevent damage in the future. Combining stretching and activation is therefore optimal to create a stronger and bigger muscle.
On the other hand, there are some theoretical benefits of using partial reps for muscle growth, such as increased metabolic stress. However, this is likely only relevant when training at a low intensity when there is otherwise not enough tension in the muscle for high muscle activation. (If you don’t understand how muscle grows in response to tension, read my article on structural balance in Alan Aragon’s Research Review where I explain this.) So far, partial reps have at best resulted in equal muscle growth as full reps in research.
And yes, that means most pro bodybuilders are training in a suboptimal way. If you can’t fathom the idea that a largely poorly educated and underground subculture’s intuitive way of manipulating the human physiology is not perfect, you have much to learn about this world.
So how does this all fit together? It depends on your goal.
Partial reps do not seem to have any advantage over full reps to stimulate muscle growth. Full reps stimulate muscle activity over the entire muscle’s length. They also stretch the muscle under high tension. Exercise selection and accommodating the resistance curve to your strength curve are generally superior methods of adding variety to bodybuilding training than partial reps.
Including partial reps can be beneficial in advanced trainees to strengthen parts of a movement as per the specificity principle. Geared powerlifters in particular can benefit from strengthening their lock-out due to the lack of passive assistance they get from knee wraps, squat & deadlift suits and bench shirts at the end of these exercises.
Novices are better off building a good strength base by sticking to full ROM training, because they are not developed enough to require ROM-specific training.
Partial reps for many exercises allow for greater power production, which can benefit power development. Just as for strength training, these benefits are greater for more advanced trainees.
Bayesian bodybuilder, popular science author and online personal trainer, Menno Henselmans helps serious trainees attain their ideal physique using scientific and Bayesian methods. Follow him on Facebook or Twitter and check out his website for more free articles.
Are you a fitness professional looking to further your education? Have a look at Menno’s course for personal trainers.
1. Specificity of limited range of motion variable resistance training. Graves JE, Pollock ML, Jones AE, Colvin AB, Leggett SH. Med Sci Sports Exerc. 1989 Feb;21(1):84-9.
2. Effect of range of motion on muscle strength and thickness. Pinto RS, Gomes N, Radaelli R, Botton CE, Brown LE, Bottaro M.J Strength Cond Res. 2012 Aug;26(8):2140-5.
3. An analysis of full range of motion vs. partial range of motion training in the development of strength in untrained men. Massey CD, Vincent J, Maneval M, Moore M, Johnson JT. J Strength Cond Res. 2004 Aug;18(3):518-21.
4. Influence of range of motion in resistance training in women: early phase adaptations. Massey CD, Vincent J, Maneval M, Johnson JT. J Strength Cond Res. 2005 May;19(2):409-11.
5. WEISS, L. W., FRX, A. C., WOOD, L. E., RELYEA, G. E., & MELTON, C. (2000). Comparative effects of deep versus shallow squat and leg-press training on vertical jumping ability and related factors. The Journal of Strength & Conditioning Research, 14(3), 241-247.
6. Influence of squatting depth on jumping performance. Hartmann H, Wirth K, Klusemann M, Dalic J, Matuschek C, Schmidtbleicher D. J Strength Cond Res. 2012 Dec;26(12):3243-61.
7. Impact of range of motion during ecologically valid resistance training protocols on muscle size, subcutaneous fat, and strength. McMahon GE, Morse CI, Burden A, Winwood K, Onambélé GL. J Strength Cond Res. 2014 Jan;28(1):245-55.
8. Limited range-of-motion lumbar extension strength training. Graves JE, Pollock ML, Leggett SH, Carpenter DM, Fix CK, Fulton MN. Med Sci Sports Exerc. 1992 Jan;24(1):128-33.
9. Electrodiagnosis in New Frontiers of Clinical Research. Edited by Hande Turker, ISBN 978-953-51-1118-4, (2013). Chapter 8: How Deep Should You Squat to Maximise a Holistic Training Response? Electromyographic, Energetic, Cardiovascular, Hypertrophic and Mechanical Evidence. By Gerard E. McMahon, Gladys L. Onambélé-Pearson, Christopher I. Morse, Adrian M. Burden and Keith Winwood.
10. Drinkwater, E. J., Moore, N. R., & Bird, S. P. (2012). Effects of changing from full range of motion to partial range of motion on squat kinetics. The Journal of Strength & Conditioning Research, 26(4), 890-896.
11. The Efficacy of Incorporating Partial Squats in Maximal Strength Training. Bazyler CD, Sato K, Wassinger CA, Lamont HS, Stone MH. J Strength Cond Res. 2014 Mar 20.
12. The influence of variable range of motion training on neuromuscular performance and control of external loads. Clark RA, Humphries B, Hohmann E, Bryant AL. J Strength Cond Res. 2011 Mar;25(3):704-
13. Muscle growth in response to mechanical stimuli. Goldspink DF, Cox VM, Smith SK, Eaves LA, Osbaldeston NJ, Lee DM, Mantle D. Am J Physiol. 1995 Feb;268(2 Pt 1):E288-97.
14. Mechanical stimulation improves tissue-engineered human skeletal muscle. Powell CA, Smiley BL, Mills J, Vandenburgh HH. Am J Physiol Cell Physiol. 2002 Nov;283(5):C1557-65.
15. Expression of insulin growth factor-1 splice variants and structural genes in rabbit skeletal muscle induced by stretch and stimulation. McKoy G, Ashley W, Mander J, Yang SY, Williams N, Russell B, Goldspink G. J Physiol. 1999 Apr 15;516 ( Pt 2):583-92.
16. Changes in muscle fibre type, muscle mass and IGF-I gene expression in rabbit skeletal muscle subjected to stretch. Yang H, Alnaqeeb M, Simpson H, Goldspink G. J Anat. 1997 May;190 ( Pt 4):613-22.
17. Changes in muscle mass and phenotype and the expression of autocrine and systemic growth factors by muscle in response to stretch and overload. Goldspink G. J Anat. 1999 Apr;194 ( Pt 3):323-34.
18. McMahon, G., Morse, C. I., Burden, A., Winwood, K., & Onambélé, G. L. (2014). Muscular adaptations and insulin‐like growth factor‐1 responses to resistance training are stretch‐mediated. Muscle & nerve, 49(1), 108-119.
by Bret Contreras April 10, 2015
Today’s guest post is a recipe from Alex Navarro and Mary Gines, two friends of mine who moved to the Phoenix area to start their online blog FitLivingFoodies.com. They’ve both...
The post RECIPE: The Reuben Quiche (Low Carb, Gluten-free, Paleo-friendly) appeared first on Bret Contreras.
by Bret Contreras January 30, 2015
LESSONS FROM CHINA by Dr. John Rusin RECENT OLYMPIC SUCCESS Many have predicted the demise of the American athlete over the course of the last century, but today, more than...
by Bret Contreras January 02, 2015
Considerations in Athletic Performance Enhancement Training: Athlete Weight Room Preparation Robert A. Panariello MS, PT, ATC, CSCS Professional Physical Therapy Professional Athletic Performance Center New York, New York During my...
The post Considerations in Athletic Performance Enhancement Training: Athlete Weight Room Preparation appeared first on Bret Contreras.
Welcome to the online store of Bret Contreras, considered by many to be the world’s foremost expert on glute training. Here you can purchase Personalised Programming, access to seminars, the Hip Thruster and more.
Sign up to get the latest on sales, new releases and more …