Barbell vs. Machine: What exercise increases testosterone 25% and growth hormone 200%?

Study Compares Squats Against the Leg Press

“There is simply no other exercise, and certainly no machine, that produces the level of…muscular stimulation and growth…than the correctly performed full squat.”

– Mark Rippetoe

Mark Rippetoe’s quotation from Starting Strength is a timeless reminder of how to prioritize strength training. If you want to be strong, ditch the machines and pick up a barbell. Rippetoe based this statement on his experience with countless athletes. The evidence of experience is powerful, but until now it’s all we had to support the idea that free weight exercises provide better results than machines.

A 2014 study in the Journal of Strength and Conditioning Research answered this question. Researchers asked, “What type of exercise elicits the stronger hormonal response – machines or free weights?” They compared the leg press and back squat to test of which could produce the most testosterone and growth hormone.

Photo courtesy of Karl Buchholtz.

Barbell squats produced significantly higher levels of testosterone and growth hormone than the leg press. At the greatest difference, which occurred during the workout, testosterone was 25% higher when performing full squats. Squats also produced a full 200% more growth hormone during the workout.

So is the leg press a bad exercise? No. My father has done high rep leg presses with heavy weight for years, and he swears by them. But at 75, he has more time than most people. We all want to get the best results possible, but most of us have limited time and energy to work out. So it makes sense to use your time and energy on exercises that provide the best results. If you can do them safely, do barbell squats.


Summarized from: Jeff Barnett at Breaking Muscle

1. Aaron Shaner, et al. The acute hormonal response to free weight and machine weight resistance exercise. Journal of Strength & Conditioning Research. POST ACCEPTANCE, 22 November 2013. doi: 10.1519/JSC.0000000000000317

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