Squat Deeper To Jump Higher? Don’t Be So Sure…

Last week came the straw that broke the camel’s back. Ever since a particular study was published online last February, coaches and trainers have been shamelessly using it to justify their own practices. That study is the following –

Hartmann H, Wirth K, Klusemann M, Dalic J, Matuschek C, Schmidtbleicher D.

Influence of squatting depth on jumping performance.

Journal of Strength and Conditioning Research. 26(12):3243-61. 2012.

Yesterday I posted Charles Poliquin’s article in which he ‘disseminated’ this very study – I suggest you give it a read if you’ve not already.

Hartmann et al concluded that:

“Deep front and back squats guarantee performance-enhancing transfer effects of dynamic maximal strength to dynamic speed-strength capacity of hip and knee extensors compared with quarter squats.”

Great stuff. We probably all thought that anyway right? But now we have science to back us up when the evil sports coach says that we can’t get their athletes squatting bum to floor. I like the way they use the term ‘guarantee’ as well – strong isn’t it?

Conformation bias

Is this how science should work though? Looking for information to support an argument we’re not prepared to lose? This is called confirmation bias. Science Daily describes this as:

“a phenomenon wherein decision makers have been shown to actively seek out and assign more weight to evidence that confirms their hypothesis, and ignore or underweigh evidence that could disconfirm their hypothesis”

I know that I’ll have been guilty of this on many occasions… and will be in the future. It’s human nature at the end of the day. However, I make damn well sure of one thing…

If I’m going to make recommendations based on the back of a particular research study then I make sure I know the research study.

What did Hartmann et al do?

The study compared 3 training groups. A group of 20 trained deep front squats, a group of 20 trained deep, high-bar back squats. Both of these groups trained with free weights and ‘deep’ was classed as below parallel. All good so far. The ¼ squat group (n=19) trained quarter squats to a knee angle of 120o in a Jones machine (a Smith machine that allows horizontal movement). Ah. This wasn’t in the abstract. Did anyone who cited this study read this far?

Some points

  • Is a machine, even a 3D one, comparable to free weights?
  • Even meatheads squat lower than 120o and there’s quite a big difference between 120o and ‘deep’. Would it be enough to squat at 90o?
  • Would athletes solely train a partial ROM? Like it or not, not everyone can squat deep. You can get around the inability to perform full squats by using other exercises to train in positions of deep knee flexion.


I suppose I should end with a conclusion as this has turned into a bit of a science rant…

You can’t say that you need to ‘squat deep to jump higher’ solely on the basis of this study.

That being said, I do expect you squat deep. Why? Because I said so… and now that I’ve said that you can cite me on it 😉

Rant over.


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