The Science of Squat Depth

One of those endless debates always comes back to should we squat full range of motion? Questions follow such as: Does it hurt our knees? Should our knees track over our toes? Does it inhibit muscular strength? Does it impede on performance doing full squats versus doing quarter squats? 

Quarter squat technique and quarter squat execution has been popularized by people like Joel Seedman. But what is the difference between the quarter squat (squatting to a range of 115 to 125 degrees) versus someone doing a full squat (where there hamstrings and thighs are just draped over their calves)? Which is better for sports performance? Which is better to force production, development, and muscular impulse?


Fortunately, we have a full blown study that has analyzed a quarter back squat and compated it to a full depth front squat and a full depth back squat while containing a control group that squatted only to around 90 degrees.

The Researchers

Hartman, Wirth, Dalic, Matuschek, and Schmidtbleicher were were German researchers from the Institute of Sports Sciences. In conjuction with Klusemann, from the Australian Institute of Sport, these researchers  analyzed the influence of squatting depth on absolute strength and jumping performance. The scientists selected moderately trained athletes to do various strength tests. For instance, they would have selected athletes do a quarter squat to around 120 degrees and work up to a maximal single as a pre-test. Three days later, they would have athletes do a full range of motion front squat. Three days later they would have the athletes do a full range of motion back squat. All of the movements would be tested to see where the athletes were starting.


The athletes also had their counter movement jump tested. The athletes also had to perform a squat jump. This was also tested with maximal voluntary contractions (MVC). The scientists tested MVC by using a leg press. The leg press was put in an isometric positions so the athletes could push into the pedal as hard as they possibly could to measure the isometric force. This was done at 120 degrees to see if there was some carryover from the quarter back squat strength gain.


In parallel, while doing the MVC test, the scientists established athletes’ maximal rate of force development by having the athletes push into the resisting force and hold that for three to five seconds as hard as they possibly can. This allowed the scientists to see how long the moderately trained athletes could hold the muscular impulse.

23 Women And 36 Men

All of the information gathered led into the discussion of how to evaluate the quarter squats, front squat, back squat, transfer into counter movement jumps, squat jumps, MVC, and the MFRD, and find the results and figure out how it applies to sports.   


The study had 23 women inside the research project and 36 men. The individuals were moderately trained, meaning they weren’t rookies nor were they super-trained, elite athletes. Remember, every athlete was tested upfront with the different pre-tests. The athletes were then put into a specific training block.


The specific training blocks were influenced by periodizaiton developed by Schmidtbleicher and a colleague. The style of periodization is similar to undulating periodization. Schmidtbleicher has had a big influence on Garage Strength’s Parabolic Periodization. Specifically in this study, the periodization spent 8 week developing hypertrophy to increase the size of the contractile tissue. After the 8 weeks of hypertrophy training, there was 2 weeks of a strength-power phase to enhance the innervation of the larger, contractile tissue.


The study totaled at 10 weeks and allowed everyone to see what ended up happening based on the transfer of the various squat depths to one another and the other tests used.


A quick aside, reading through the article, when doing the quarter squat test they used a Smith machine that also moved horizontally. The reason the scientists used a Smith machine is because they knew the quarter squat load would be much higher. The Smith machine was used for safety precautions. One individual inside of the test maxed out the quarter squat test before the study even began. The individual quarter squatted 380 kilos and did not fail based upon the scientists determination. One individual, who was part of the full back squat group, did not get tested on the back end of the quarter squat because he had already maxed out the test on the first time through. 

Analyzing The Results

Again, the athletes were trained over 10 weeks, twice a week, and the athletes were even given verbal encouragement from the testers. The athletes even had one or two forced reps. The study was pretty hard and had a high success rate with who executed the actual study.


Let’s discuss the full range of motion front squat and back squat first. Athletes who performed full range of motion front squat and full range of motion back squat improved more in the counter movement jump when compared to the control group and quarter squat group. That shows that there was not a direct angular transfer from the quarter squat because the full range of motion back squat and full range of motion front squat was higher than the control and the quarter squat.


With the squat jump, which is starting at 90 degrees with no eccentric, the front squat full range of group was the best group for the squat jump, out classing the back squat, quarter squat, and control groups. 


Every athlete was tested in all the squat variations in the beginning and at the end. Of course, the full range of motion front squat group did the best in increasing their full range of motion front squat. The back squat full range of motion also saw an increase in their front squat. The control group and quarter squat groups did not see an improvement in their full range of motion front squat. In fact, the quarter squat group saw a decrease in the execution of their maximal deep front squat.


The full range of motion back squat group saw the biggest increas in their deep back squat post-test. The full range of motion front squat group also saw an increase in their deep back squat. The control group and the quarter squat group, specifically the quarter squat group, saw a massive decline in their full range of motion back squat.  


Now the quarter squat group got really, really strong in the quarter squat range of motion but it did not transfer over to the full range of motion. It also didn’t impact the counter movement jump or the squat jump. It also didn’t transfer to the full range of motion of the front squat and back squat.

MVC and MRFD 

The next test involved the MVC as the athletes pushed into a leg press at 120 degrees. The test is almost identical in angle to what is being trained in the quarter squat. When the isometric post-test occurred on the leg press machine to tell us if there was an angular transfer, which is important, at least trained in this manner, there was no transfer! In fact the maximal voluntary contraction from the quarter squat group declined substantially. That’s pretty crazy. Along with that, the MVC had no significant increase in any groups except for the front squats. 


That takes us to the MRFD. There was a decline among all groups over the 10 week period doing squat training twice a week. 

Discussion

Essentially whatever squat variation that was trained was where the athletes got really strong. Seems to check out. 


The researchers expected a couple things would happen. They thought their would be minimal change in the counter movement jump and squat jump. They also thought there would be minimal change in the dynamic strength. Some of the comments inside the study talk about loss of motivation, not training jumps, and the training was hard.


The focus of the study was on squats. Specifically, the researchers wanted to see if there was angular transfer from the strength gains made from training quarter squats. Diving deep, the study showed there is no angular transfer at all from training like this periodization for 10 weeks. Does that mean there will never be angular transfer? No. But in this 10 week study, the results show there is no angular transfer. In fact, based on how the squat variations transferred, the full range of motion back squat and full range of motion front squat transferred to each other and also increased the quarter squat. The quarter squat did not transfer over the full range of motion variations.


Which leads us to hypertrophy. Obviously, based on this study, full range of motion movements increase hypertrophy much more significantly. This is seen in other studies as well. 


Thinking about this more, MVC and MRFD probably take a lot longer than 10 weeks to improve. The data indicates that the squat variations had a direct impact on that similar variation, meaning full range of motion transferred to full range of motion. They didn’t do jump training. In theory, the test could be reproduced using contrast methods, coupling the variations of squats with variations of jump training to see what may result.

Application To Sports Performance

Hypertrophy training transfers very well to strength as demonstrated through this study. The quarter squat does not increase the size of the actual contractile muscle so the innervations will not be as substantial as performing full range of motion movements. Training a larger muscle how to fire more effectively creates a stronger muscular impulse that, in theory, can lead to greater rates of force development. Clearly that can’t happen in 10 weeks.


Perhaps because we are doing a quarter squat test that is really, really heavy and done slower, it might be better to do something like a linebacker jerk, which is a jerk that is done from the blocks starting in a quarter squat. I would love to see if this quarter squat movement position transfers to a vertical jump, especially if it is paired with full range of motion squats. 


So we could put in a group doing a behind the neck jerk with a dip and a group who does a behind the neck jerk without the dip (the linebacker jerk) to see how paired with the various squat movements to see what the results would be. 

Recap

The takeaway from this article is that the transfer of training is extremely important for sports performance. Doing full range of motion movements lifting will increase maximal strength which will likely transfer to the competitive environment. The angular transfer of the athlete stance does not transfer very well, especially if there is no jump based training being performed. 


It boils down to athletes need to do work that is based around absolute strength and performed with a full range of motion. But because there is no increase in the jumping heights and MVC and MRFD, we have to also be performing full range of motion technical coordination movements and plyometric work. 


We also know that quarter squats are worthless based off of max strength.


Hartmann, Hagen. “Influence of Squatting Depth on Jumping Performance : The Journal of Strength & Conditioning Research.” Journals LWW, Official Journal of the National Strength and Conditioning Association, Dec. 2012, https://journals.lww.com/nsca-jscr/Fulltext/2012/12000/Article.10.aspx.

  


DANE MILLER

Dane Miller is the owner and founder of Garage Strength Sports Performance. He works with a select handful of clients on building comprehensive programs for fitness and nutrition. Several times a year he leads a workshop for coaches, trainers, and fitness enthusiasts.

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