Think of Arnold Schwarzenegger training in his prime and you’ll probably picture him performing heavy deadlifts, bench presses and barbell curls. Smith machine box squats probably don’t spring to mind.
Yet in his 1977 documentary Pumping Iron, the movement plays a central role in Arnold’s leg training. He believed it built his quads more effectively than the traditional squats he’d relied on previously, even making it a bigger priority than his famous twice-daily leg sessions.
Which makes its omission from many modern breakdowns of Arnold’s workouts all the more surprising.
Why Arnold Loved Smith Machine Box Squats
After years of performing deep back squats, Arnold began questioning whether they were the best option for building the physique he wanted on stage.
Writing about squatting in a 1976 article, he argued that while full squats developed strength and overall leg size, they also built his back and glutes more than he wanted, leaving his quads ‘bulky and shapeless’.
With Mr Olympia titles on the line, he looked for another option.
Eventually, Schwarzenegger switched to Smith machine squats, believing they allowed him to target his quads more effectively while reducing the amount of work done by stabilising muscles such as the core and lower back.
‘I have reverted to using the vertical sliding Smith machine for my squats. This machine enables me to concentrate on my legs,’ he wrote. ‘The movement gives my thighs an incredible burn and gets the more lateral muscles. I always do this one before a contest. I burn out as many reps as I can, never completing a movement. If you lock out, you give your muscles a chance to rest, and that’s not what you want. You have to torture the muscle with unusual training so that it will respond.
‘I used to use a lot of weight on the squat. Not anymore. I find now that concentration lends its own form of resistance. By thinking I can direct the effort, I can make every movement count, not only the sets. By doing the sliding squat on the sliding Smith machine, I am able to concentrate using less weight. I direct my attention to what the thighs are doing. I literally think the definition into them. The pleasure of my thought overrides the pain. The positive aspects of cuts and veins and shape spur me on, and the whole thing becomes a labour of love.’
Why Smith Machine Box Squats Work
Schwarzenegger’s goal wasn’t simply to squat more weight – it was to maximise quad growth.
He believed the bottom portion of a full squat shifted more of the work towards the glutes. By squatting onto a box set at roughly parallel, he could stop at the depth where he felt his quads were working hardest, maintaining as much tension on the target muscle as possible.
Using the Smith machine also allowed him to push closer to failure. With less demand on the core and lower back, the quads could shoulder more of the work, while the fixed bar path helped him maintain a more upright torso and greater knee flexion.
‘I can place my feet forward of the vertical line of my body, and I can’t fall back, like I would using a barbell. Thus, with my back straight, feet about 10 inches apart, and my knees straight ahead, I do tension squats, going three-quarters of the way down and coming up to a position a quarter of the way from the top,’ he added.
The Smith machine also makes training to failure safer, thanks to its built-in safety catches.
How to Do Smith Machine Box SquatsSet up a box or flat bench securely behind you inside a Smith machine. The height should allow your thighs to reach roughly parallel with the floor when seated.Position your feet a few inches in front of the bar, with it resting across your upper traps rather than your neck. Brace your upper back and core.Grip the bar just outside shoulder width and pull your elbows down towards your torso.Unrack the bar by extending your legs and rotating it off the hooks.Step into your squat stance, with your feet slightly wider than shoulder-width and your toes turned out slightly.Push your hips back and lower under control, driving your knees out as you descend.Gently touch the box without bouncing or fully relaxing.Drive through your whole foot to stand back up, squeezing your glutes at the top.Once you’ve completed your final rep, rotate the bar back onto the hooks to re-rack it safely.